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  • 1. Abbaszadeh, A
    et al.
    Taherzadeh, Mohammad J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Effect of extraction conditions on yield and purity of citrus pectin by sulfuric and hydrochloric acids2009Konferensbidrag (Refereegranskat)
  • 2.
    Abedinifar, S.
    et al.
    Department of Chemical Engineering, Isfahan University of Technology.
    Karimi, K
    Department of Chemical Engineering, Isfahan University of Technology.
    Khanahmadi, M.
    Isfahan Agriculture and Natural Resources Research Centre.
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Ethanol production by Mucor indicus and Rhizopus oryzae from rice straw by separate hydrolysis and fermentation2009Ingår i: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 33, nr 5, s. 828-833Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Rice straw was successfully converted to ethanol by separate enzymatic hydrolysis and fermentation by Mucor indicus, Rhizopus oryzae, and Saccharomyces cerevisiae. The hydrolysis temperature and pH of commercial cellulase and β-glucosidase enzymes were first investigated and their best performance obtained at 45 °C and pH 5.0. The pretreatment of the straw with dilute-acid hydrolysis resulted in 0.72 g g-1 sugar yield during 48 h enzymatic hydrolysis, which was higher than steam-pretreated (0.60 g g-1) and untreated straw (0.46 g g-1). Furthermore, increasing the concentration of the dilute-acid pretreated straw from 20 to 50 and 100 g L-1 resulted in 13% and 16% lower sugar yield, respectively. Anaerobic cultivation of the hydrolyzates with M. indicus resulted in 0.36-0.43 g g-1 ethanol, 0.11-0.17 g g-1 biomass, and 0.04-0.06 g g-1 glycerol, which is comparable with the corresponding yields by S. cerevisiae (0.37-0.45 g g-1 ethanol, 0.04-0.10 g g-1 biomass and 0.05-0.07 glycerol). These two fungi produced no other major metabolite from the straw and completed the cultivation in less than 25 h. However, R. oryzae produced lactic acid as the major by-product with yield of 0.05-0.09 g g-1. This fungus had ethanol, biomass and glycerol yields of 0.33-0.41, 0.06-0.12, and 0.03-0.04 g g-1, respectively. 

  • 3. Abedinifar, Sorahi
    et al.
    Karimi, Keikhosro
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Khanahmadi, Morteza
    Taherzadeh, Mohammad J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Ethanol production by Mucor indicus and Rhizapus oryzae from rice straw by separate hydrolysis and fermentation2009Ingår i: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 33, nr 5, s. 828-833Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Rice straw was successfully converted to ethanol by separate enzymatic hydrolysis and fermentation by Mucor indicus, Rhizopus oryzae, and Saccharomyces cerevisiae. The hydrolysis temperature and pH of commercial cellulase and beta-glucosidase enzymes were first investigated and their best performance obtained at 45 degrees C and pH 5.0. The pretreatment of the straw with dilute-acid hydrolysis resulted in 0.72 g g (1) sugar yield during 48 h enzymatic hydrolysis, which was higher than steam-pretreated (0.60 g g (1)) and untreated straw (0.46 g g(-1)). Furthermore, increasing the concentration of the dilute-acid pretreated straw from 20 to 50 and 100 g L-1 resulted in 13% and 16% lower sugar yield, respectively. Anaerobic cultivation of the hydrolyzates with M. indicus resulted in 0.36-0.43 g g(-1) ethanol, 0.11-0.17 g g(-1) biomass, and 0.04-0.06 g g(-1) glycerol, which is comparable with the corresponding yields by S. cerevisiae (0.37-0.45 g g(-1) ethanol, 0.04-0.10 g g(-1) biomass and 0.05-0.07 glycerol). These two fungi produced no other major metabolite from the straw and completed the cultivation in less than 25 h. However, R. oryzae produced lactic acid as the major by-product with yield of 0.05-0.09 g g(-1). This fungus had ethanol, biomass and glycerol yields of 0.33-0.41, 0.06-0.12, and 0.03-0.04 g g(-1), respectively. Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved.

  • 4. Abtahi, Zhohreh
    et al.
    Millati, Ria
    Niklasson, Claes
    Taherzadeh, Mohammad J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Ethanol production by Mucor indicus at high glucose and ethanol concentrations2010Ingår i: Minerva biotecnologica (Testo stampato), ISSN 1120-4826, E-ISSN 1827-160X, Vol. 22, nr 3-4, s. 83-89Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Mucor indicus was cultivated under aerobic and anaerobic conditions to study its tolerance against high concentration of glucose up to 350 g/L and ethanol up to 120 g/L present in the medium. The fungus could grow well even in 350 g/L glucose and produce ethanol, but it was able to assimilate the entire glucose when its concentration was less than 200 g/L. On the other hand, M. indicus produced ethanol as the main product with yield and concentration up to 0.45 g/g and 73 g/L, respectively, while glycerol, its only major byproduct, was produced up to 24 g/L. However, the fungus was not so tolerant against exogenously added ethanol, and it could not grow with more than 40 g/L added ethanol to the culture. Under aerobic conditions, M. indicus displayed different morphology, switching from long filamentous to yeast-like growth forms by increasing initial glucose concentration. This implies that yeast-like growth can be induced by growing M. indicus at high glucose concentration. Under anaerobic conditions, only one yeast-like form was observed.

  • 5.
    Adekunle, Kayode
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Ketzscher, Richard
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    High performance natural fibre hybrid composites based on biobased thermoset resins for use in technical applications2009Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Health related issues, stringent environmental protection policies, search for cost effective and alternative materials and quest for renewability, sustainability and high performance materials for technical applications has led to an intense research in manufacturing biobased composites which are based on renewable thermosetting resins and natural fibres. The combination of biobased thermosetting resins with two different natural fibre reinforcements could lead to improved mechanical properties of the composite. Biobased thermoset polymers are comparable to the synthetic thermosetting polymers from petrochemicals. In this study, two different biobased resins were used as matrix and both non woven flax fibre and woven flax fabric were combined as reinforcements. The composites were made by compression moulding process. The fibres were hand laid-up and impregnation was done manually. The curing temperature was 170°С and at 40 bar. The stacking sequence of the fibres was in different orientations such as 0º, +45º and 90º. The manufactured hybrid composites have high tensile strength and stiffness and the flexural strength and modulus was also high. These composites can compete favourably with glass fibre reinforced composites in terms of strength and stiffness.1, 2 A tensile strength of about 119 MPa and Young’s modulus of 13.8 GPa was achieved, while the flexural strength and modulus is about 201 MPa and 24 GPa respectively. For the purpose of comparison, composites were made with the combination of woven fabric and e-glass fibre. One ply of an e-glass fibre mat was put in the mid-plane and this increased the tensile strength considerably up to 168 MPa. Some of the composites were made with the resin blended with styrene and the results show a higher modulus.

  • 6.
    Adekunle, Kayode
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Åkesson, Dan
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Synthesis of reactive soybean oils for use as a biobased thermoset resins in structural natural fiber composites2009Ingår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 115, nr 6, s. 3137-3145Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Biobased thermosets resins were synthesized by functionalizing the triglycerides of epoxidized soybean oil with methacrylic acid, acetyl anhydride, and methacrylic anhydride. The obtained resins were characterized with FTIR, 1H-NMR, and 13C-NMR spectroscopy to confirm the functionalization reactions and the extent of epoxy conversion. The viscosities of the methacrylated soybean oil resins were also measured for the purpose of being used as a matrix in composite applications. The cross-linking capability was estimated by UV and thermally initiated curing experiments, and by DSC analysis regarding the degree of crosslinking. The modifications were successful because up to 97% conversion of epoxy group were achieved leaving only 2.2% of unreacted epoxy groups, which was confirmed by 1H-NMR. The 13C-NMR confirms the ratio of acetate to methacrylate methyl group to be 1 : 1. The viscosities of the methacrylated soybean oil (MSO) and methacrylic anhydride modified soybean oil (MMSO) were 0.2 and 0.48 Pas, respectively, which indicates that they can be used in resin transfer molding process.

  • 7.
    Aghajani, M
    et al.
    Department of Chemical Engineering, Babol Noushirvani University of Technology.
    Rahimpour, A
    Department of Chemical Engineering, Babol Noushirvani University of Technology.
    Amani, H
    Department of Chemical Engineering, Babol Noushirvani University of Technology.
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Rhamnolipid as new bio-agent for cleaning of ultrafiltration membrane fouled by whey2018Ingår i: Engineering in Life Sciences, ISSN 1618-0240, E-ISSN 1618-2863, Vol. 18, nr 5, s. 272-280Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this work, rhamnolipid biosurfactant as an eco-friendly and biodegradable cleaning agent was produced by Pseudomonas aeruginosa bacteria and was used to evaluate the chemical cleaning efficiency of whey fouled ultrafiltration membranes. Thin layer chromatography (TLC) and Fourier transform infrared spectroscopy (FTIR) confirmed the successful synthesis of rhamnolipid. The produced rhamnolipid was compared to chemical cleaners including sodium hydroxide (NaOH), sodium dodecyl sulfate (SDS) and Tween 20. Ultrafiltration membranes used for fouling and cleaning analysis were prepared using phase inversion via immersion precipitation technique. For studying the fouling mechanisms, Hermia's model adapted to cross-flow was used. From the fouling mechanism experiments, it was found that the complete blocking and cake formation were the dominant fouling mechanisms. The highest values of cleaning efficiency were achieved using rhamnolipid and NaOH as cleaning agents with the flux recovery of 100%, but with considering the low concentration of the rhamnolipid used in the cleaning solution compared to NaOH (0.3 versus 4 g/L for NaOH), its application is preferred. 

  • 8.
    Agnhage, Tove
    et al.
    Högskolan i Borås, Institutionen Textilhögskolan.
    Nierstrasz, Vincent
    Högskolan i Borås, Institutionen Textilhögskolan.
    Perwuelz, A.
    Guan, J.P.
    Chen, G.Q.
    Eco-design innovative methods for fabric finishing2014Konferensbidrag (Övrigt vetenskapligt)
  • 9.
    Ahlström, Peter
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Gebäck, Tobias
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Johansson, Erik
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Bolton, Kim
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Water absorption in polymers2010Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    In this work two different examples of water absorbtion in polymers are studied by Monte Carlo simulations. Both of them are of large technical and commercial impotance. The first example is the water absorption in polyethylene cables where the water absorption plays a crucial role in the degradation of the cable insulation and thus should be as low as possible. The second example is bio-based superabsorbents made from denatured protein where water absorption capability is the prime desired property. Methods Gibbs Ensemble Monte Carlo simulations [1] were used to study the hydration of polymers. All simulations are performed with two boxes, one of which is filled with water at the start of the simulation, whereas the other contains polymer molecules and possible ions. The polymer molecules are not allowed to swap boxes whereas the water molecules are allowed to do so thus constituting an osmotic Gibbs ensemble [2]. For the polyethylene a connectivity-altering algorithm was used whereas the protein molecules were simulated using a side-chain regrowth model in addition to traditional Monte Carlo moves. For the polyethylene, the TraPPE [3] force field was used and the protein molecules, the Amber force field [4] was used. Water was modelled using simple point charge models [5]. Electrostatic interactions are treated using Ewald summation methods. The protein molecules were of different amino acid compositions and in different conformations, e.g., β-turns and random coils obtained using the amorphous cell method[6]. Studies were made with different degrees of charging on, e.g., lysine side chains mimicking different ionization states. Results The studies of polyethylene revealed the importance of ions left from the polymerisation catalyst for the absorbtion of water and the concomitant degradation of polyethylene cable insulation. Also the absorption properties of the protein molecules is strongly related to the presence of charged groups and fully charged protein molecules absorb large amounts of water. However, neither native nor denatured protein molecules show superabsorbing properties (i.e. absorbing hundreds of times their own mass) as they show in experimental studies and the reasons for this discrepancy will be discussed. References 1. A.Z. Panagiotopoulos, Mol. Phys. 61, 813 (1987). 2. E. Johansson, K. Bolton, D.N. Theodorou, P. Ahlström, J. Chem. Phys., 126, 224902 (2007). 3. M.G. Martin, and J.I. Siepmann, J. Phys. Chem. B, 103, 4508-4517 (1999). 4. W.D. Cornell, P. Cieplak, C.I. Bayly, I.R. Gould, K.M. Merz Jr, D.M. Ferguson, D.C. Spellmeyer, T. Fox, J.W. Caldwell, P.A. Kollman (1995). J. Am. Chem. Soc. 117, 5179–5197. 5. H. J. C. Berendsen, J. P. M. Postma and W. F. van Gunsteren, in Intermolecular Forces, B. Pullman, ed. (Reidel, Dordrecht, 1981) p. 331; H. J. C. Berendsen, J. R. Grigera and T. P. Straatsma, J. Phys. Chem. 91, 6269 (1987). 6. D.N. Theodorou, U.W. Suter, Macromolecules, 18, 1467 (1985).

  • 10. Akbari, H.
    et al.
    Karimi, K
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Lundin, M
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Taherzadeh, Mohammad J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Optimization of baker's yeast drying in industrial continuous fluidized-bed dryer2012Ingår i: Food and Bioproducts Processing, ISSN 0960-3085, E-ISSN 1744-3571, Vol. 90, nr 1, s. 52-57Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Instant active dry baker's yeast is a well-known product widely used for leavening of bread, produced by fermentation, and usually dried by hot air to 94–96% dry matter content. Multi-stage fluidized bed drying process is a commercial effective method for yeast drying. In this work, optimum operating parameters of an industrial continuous fluidized bed dryer for the production of instant active dry yeast were investigated. The dryer contained four zones separated with moving weirs. The operating conditions such as temperature, loading rate of compressed yeast granules, and hot air humidity had direct effects on both yeast activity and viability. The most important factors that affected the quality of the product were loading rate and the operational temperature in each zone on the bed. Optimization was performed for three loading rates of the feed to the dryer, using response surface methodology for the experimental design. The most significant factor was shown to be the loading rate with mean fermentation activity values of 620, 652, and 646 cm3 CO2/h for 300, 350, and 400 kg/h loading rates, respectively. The data analysis resulted in an optimal operating point at a loading rate of 350 kg/h and temperatures of zones 1, 2, 3, and 4 controlled at 33, 31, 31, and 29 °C, respectively. The best activity value was predicted as 668 ± 18 cm3 CO2/h, and confirmation experiments resulted in 660 ± 10 cm3 CO2/h. At the same operating point, the average viability of the cells was predicted as 74.8 ± 3.7% and confirmed as 76.4 ± 0.6%. Compared with the normal operating conditions at the plant, the optimization resulted in more than 12% and 27% improvement in the yeast activity and viability, respectively.

  • 11.
    Akinbomi, Julius
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Brandberg, Tomas
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Sanni, Sikiru A.
    Taherzadeh, Mohammad J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Development and Dissemination Strategies for Accelerating Biogas Production in Nigeria2014Ingår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 9, nr 3Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Following the worsening energy crisis of unreliable electricity and unaffordable petroleum products coupled with the increase number of poverty-stricken people in Nigeria, the populace is desperately in need of cheap alternative energy supplies that will replace or complement the existing energy sources. Previous efforts by the government in tackling the challenge by citizenship sensitization of the need for introduction of biofuel into the country’s energy mix have not yielded the expected results because of a lack of sustained government effort. In light of the shortcomings, this study assesses the current potential of available biomass feedstock for biogas production in Nigeria, and further proposes appropriate biogas plants, depending on feedstock type and quantity, for the six geopolitical zones in Nigeria. Besides, the study proposes government-driven biogas development systems that could be effectively used to harness, using biogas technology, the estimated 270 TWh of potential electrical energy from 181 million tonnes of available biomass, in the advancement of electricity generation and consequent improvement of welfare in Nigeria.

  • 12.
    Akinbomi, Julius
    et al.
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Evaluation of Fermentative Hydrogen Production from Single and Mixed Fruit Wastes2015Ingår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 8, nr 5, s. 4253-4272Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The economic viability of employing dark fermentative hydrogen from wholefruit wastes as a green alternative to fossil fuels is limited by low hydrogen yield due to theinhibitory effect of some metabolites in the fermentation medium. In exploring means ofincreasing hydrogen production from fruit wastes, including orange, apple, banana, grapeand melon, the present study assessed the hydrogen production potential of singly-fermentedfruits as compared to the fermentation of mixed fruits. The fruit feedstock was subjected tovarying hydraulic retention times (HRTs) in a continuous fermentation process at 55 °C for47 days. The weight distributions of the first, second and third fruit mixtures were 70%,50% and 20% orange share, respectively, while the residual weight was shared equally bythe other fruits. The results indicated that there was an improvement in cumulativehydrogen yield from all of the feedstock when the HRT was five days. Based on the resultsobtained, apple as a single fruit and a fruit mixture with 20% orange share have the mostimproved cumulative hydrogen yields of 504 (29.5% of theoretical yield) and 513 mL/gvolatile solid (VS) (30% of theoretical yield ), respectively, when compared to other fruits.

  • 13.
    Akinbomi, Julius
    et al.
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Wikandari, Rachman
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Enhanced Fermentative Hydrogen and Methane Production from an Inhibitory Fruit-Flavored Medium with Membrane-Encapsulated Cells.2015Ingår i: Membranes, ISSN 2077-0375, E-ISSN 2077-0375, Vol. 5, nr 4Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study focused on the possibility of improving fermentative hydrogen and methane production from an inhibitory fruit-flavored medium using polyvinylidene fluoride (PVDF) membrane-encapsulated cells. Hexanal, myrcene, and octanol, which are naturally produced in fruits such as apple, grape, mango, orange, strawberry, and plum, were investigated. Batch and semi-continuous fermentation processes at 55 °C were carried out. Presence of 5 g/L of myrcene, octanol, and hexanal resulted in no methane formation by fermenting bacteria, while encapsulated cells in the membranes resulted in successful fermentation with 182, 111, and 150 mL/g COD of methane, respectively. The flavor inhibitions were not serious on hydrogen-producing bacteria. With free cells in the presence of 5 g/L (final concentration) of hexanal-, myrcene-, and octanol-flavored media, average daily yields of 68, 133, and 88 mL/g COD of hydrogen, respectively, were obtained. However, cell encapsulation further improved these hydrogen yields to 189, 179, and 198 mL/g COD. The results from this study indicate that the yields of fermentative hydrogen and methane productions from an inhibitory medium could be improved using encapsulated cells.

  • 14. Alinezhad, S.
    et al.
    Mirabdollah, A.
    Forgács, Gergely
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Feuk-Lagerstedt, Elisabeth
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Sárvári Horváth, Ilona
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Expression of keratinase gene in Bacillus megaterium using an expression vector of pHIS1525.SPlipA and utilization of the resulting recombinant strain for chicken feather degradation prior to biogas production2009Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    An increasing quantity of chickens is being utilized annually in the poultry industry, producing a huge volume of chicken feather waste which presents a high quality supply of keratin. Keratinases possessing high level of keratinolytic activity on insoluble keratin play a crucial role in hydrolyzing chicken feathers. Ever since the discovery of proteolytic ability as well as water solubility of keratinase, many industrial processes regarding keratinase application have been developed. A recently invented application to handle poultry waste is to utilize feathers for biogas production. Obviously, large amount of keratinase is required to break down the keratin prior to further conversion to biogas. Previously, several researches have shown that certain bacteria are able to produce keratinase but it is still a challenge to find out which bacteria is the most reliable source for the production with high efficiency. These challenges gave rise to the molecular biologists to bring the focus on gene cloning to develop recombinant strains resulting in overproduction of keratinase. Over the course of various cloning and expression experiments of similar proteins, it was found that Bacillus megaterium could be a susceptible host cell for keratinase production. In our study, the keratinase gene from the chromosomal DNA of Bacillus licheniformis ATCC®53757 was PCR amplified and subsequently cloned into Bacillus megaterium expression vector, pHIS1525.SPlipA. Bacillus megaterium ATCC®14945 strain was transformed with the recombinant plasmid, pKERHIS1525.SPlipA. The KER gene was expressed under xylose inducible promoter, and the product was then purified using Ni-NTA affinity chromatography. After 18 h of incubation an extracellular keratinase activity of 29U ml-1 was achieved (one unit of activity was determined as the amount of enzyme required to an increase of 0.01 in A420 after 30 min of incubation at 37°C). The recombinant strain was further examined for feather degradation using intact chicken feather waste as carbon source. The chopped chicken feathers were partially degraded by the recombinant strain after three days of incubation and the total macroscopic digestion was ultimately observed after seven days resulting in a yellowish peptide rich fermentation broth. The biogas potential of the hydrolysate will be compared with that of untreated feathers by performing anaerobic batch digestion experiments.

  • 15.
    Arabi, R.
    et al.
    Department of Chemical Engineering, Isfahan University of Technology.
    Bemanian, S.
    Department of Chemical Engineering, Isfahan University of Technology.
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Rapid biodegradation of methyl tert-butyl ether (MTBE) by pure bacterial cultures2007Ingår i: Iranian Journal of Chemistry and Chemical Engineering, ISSN 1021-9986, Vol. 26, nr 1, s. 1-7Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Two pure bacterial strains capable of rapid degrading methyl tert-butyl ether (MTBE) were isolated from an industrial wastewater treatment plant, identified and characterized. These strains are able to grow on MTBE as the sole carbon and energy souces and completely mineralize it to the biomass and carbon dioxide. The strains were identified as Bacillus cereus and Klebsiella terrigena. Both strains are able to grow in the presence of 48 gl-1 MTBE in water, which is almost the maximum concentration of MTBE in the water. They were able to completely degrade 10 gl-1 MTBE in less than a day. The specific degradation rate of MTBE at optimum conditions were 5.89 and 5.78 g(MTBE) g(cells)-1 h-1 for B. cereus and K. terrigena, respectively. The biomass yield was 0.085 and 0.076 gg-1, respectively. The cultivations were carried out successfully at 25, 30 and 37 °C, while they showed the best performance at 37 °C. Neither of the strains was able to grow and degrade MTBE anaerobically.

  • 16.
    Ariyanto, T.
    et al.
    Department of Chemical Engineering, Faculty of Engineering, Universitas Gadjah Mada.
    Cahyono, R. B.
    Department of Chemical Engineering, Faculty of Engineering, Universitas Gadjah Mada.
    Vente, A.
    Environmental Science for Sustainable Energy and Technology, Avans Hogeschool.
    Mattheij, S.
    Department of Food and Agricultural Product Technology, Universitas Gadjah Mada.
    Millati, R.
    Department of Food and Agricultural Product Technology, Universitas Gadjah Mada.
    Sarto,
    Department of Chemical Engineering, Faculty of Engineering, Universitas Gadjah Mada.
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Syamsiah, S.
    Department of Chemical Engineering, Faculty of Engineering, Universitas Gadjah Mada.
    Utilization of fruit waste as biogas plant feed and its superiority compared to landfill2017Ingår i: International Journal of Technology, ISSN 2086-9614, Vol. 8, nr 8, s. 1385-1392Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Fruit waste is a part of municipal solid waste which is typically disposed of directly to a landfill site. In order to utilize this valuable renewable resource, anaerobic biological processes can be employed to convert fruit waste to biogas. This usable gas is then used to generate electricity. This paper describes a comprehensive study to set up technology for converting fruit waste to electricity via biogas production. First, the fruit waste characteristics (type and composition) were systematically evaluated, and then laboratory experiments for biogas conversion to explore gas production from the waste were carried out. The biogas plant was then designed, based on the information obtained. Finally, a comparison of biogas plant with landfill was performed using life cycle assessment (LCA) to determine environmental impacts, and economic evaluation to assess daily processing costs. The results from waste characterization in one of the biggest fruit markets in Indonesia showed that the three main component fruit types were orange (64%), mango (25%), and apple (5%). Rotten fruit contributes up to 80% of the total waste in the fruit market. Based on the experimental work, the potential gas production in the biogas plant was calculated to be approximately 1075 Nm3/day, comprising 54% methane, based on 10 tons per day of fruit waste. The comparison demonstrates that it is a better option to utilize fruit waste in a biogas plant, in terms of LCA and daily operational costs, than to dispose of it in landfill. 

  • 17. Asachi, R.
    et al.
    Karimi, K.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Taherzadeh, M.J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Fungal autolysate as a nutrient supplement for ethanol and chitosan production by Mucor indicus2011Ingår i: Biotechnology letters, ISSN 0141-5492, E-ISSN 1573-6776, Vol. 33, nr 12, s. 2405-2409Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Mucor indicus can be used to produce ethanol from a variety of sugars, including pentose's. An extract of it, produced by autolysis, could replace yeast extract in culture medium with improved production of ethanol. At 10 g l(-1), the extract gave a higher ethanol yield (0.47 g g(-1)) and productivity (0.71 g l(-1) h(-1)) compared to medium containing yeast extract (yield 0.45 g g(-1); productivity 0.67 g l(-1) h(-1)).

  • 18.
    Asadollahzadeh, Mohammadtaghi
    et al.
    Department of Pulp and Paper Technology, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.
    Ghasemian, Ali
    Department of Pulp and Paper Technology, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.
    Saraeian, Ahmadreza
    Department of Pulp and Paper Technology, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.
    Resalati, Hossein
    Department of Wood and Paper Sciences, Sari University of Agricultural Sciences and Natural Resources, Sari, Iran.
    Lennartsson, Patrik R.
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Using spent sulfite liquor for valuable fungal biomass production by Aspergilus oryzae2017Ingår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 32, nr 4, s. 630-638Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The recent and increasing interest in bioconversion of lignocellulosic wastes into value-added products has led to extensive research on various microorganisms and substrates. In this study, filamentous fungus Aspergillus oryzae was cultivated on spent sulfite liquor (SSL) from a pulp mill. The process using an airlift bioreactor (3.5 L working volume) was successfully carried out in 48 h with an airflow of 0.85 vvm (volume air per volume culture per minute) at 35°C and pH 5.5. The cultivation results showed that the fungal biomass concentration was higher in more diluted SSL. The highest and lowest fungal biomass concentrations when spore inoculation was used were 10.2 and 6.5 g/l SSL, in diluted SSL to 60 and 80%, respectively. The range of crude protein and total fat of the fungal biomass was 0.44 – 0.48 and 0.04 – 0.11 g/g biomass dry weight, respectively. All essential amino acids were present in acceptable quantities in the fungal biomass. The results obtained in this study have practical implications in that the fungus A. oryzae could be used successfully to produce fungal biomass protein using spent sulfite liquor for animal feed.

  • 19. Asadollahzadeh, Mohammadtaghi
    et al.
    Ghasemian, Ali
    Saraeian, Ahmadreza
    Resalati, Hossein
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Production of Fungal Biomass Protein by Filamentous Fungi Cultivation on Liquid Waste Streams from Pulping Process2018Ingår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 13, nr 3, s. 5013-5031Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The aim of this study was to convert the spent liquors obtained from acidic sulfite and neutral sulfite semi-chemical (NSSC) pulping processes into protein-rich fungal biomass. Three filamentous fungi, Aspergillus oryzae, Mucor indicus, and Rhizopus oryzae, were cultivated on the diluted spent liquors in an airlift bioreactor with airflow of 0.85 vvm at 35 degrees C and pH 5.5. Maximum values of 10.17 g, 6.14 g, and 5.47 g of biomass per liter of spent liquor were achieved in the cultivation of A. oryzae, M. indicus, and R. oryzae on the spent sulfite liquor (SSL) diluted to 60%, respectively, while A. oryzae cultivation on the spent NSSC liquor (SNL) diluted to 50% resulted in the production of 3.27 g biomass per liter SNL. The fungal biomasses contained 407 g to 477 g of protein, 31 g to 114 g of fat, 56 g to 89 g of ash, and 297 g to 384 g of alkali-insoluble material (AIM) per kg of dry biomass. The amino acids, fatty acids, and mineral elements composition of the fungal biomasses corresponded to the composition of commercial protein sources especially soybean meal. Among the fungi examined, A. oryzae showed better performance to produce protein-rich fungal biomass during cultivation in the spent liquors.

  • 20.
    Aski, Abolfazl Lotfi
    et al.
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Borghei, Alimohammad
    Department of Biosystem Mechanical Engineering, Islamic Azad University Tehran Science and Research Branch.
    Zenouzi, Ali
    Iranian Research Organizations for Science and Technology (IROST).
    Ashrafi, Nariman
    Department of Mechanical and Aerospace Engineering, Islamic Azad University Tehran Science and Research Branch.
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Effect of Steam Explosion on the Structural Modification of Rice Straw for Enhanced Biodegradation and Biogas Production2019Ingår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 14, nr 1, s. 464-485Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The goal of this study was to develop an operational steam explosion pretreatment for effective modification of rice straw chemical structure in order to improve its biodegradability and methane yield. The parameters of pressure (5 bar to 15 bar), moisture (0% to 70%), and time (1 min to 15 min) were studied in steam explosion pretreatment. The steam explosion efficiency was investigated according to the changes in crystallinity structure and chemical composition on rice straw, as well as the methane yield from straw. Steam explosion changed the structure linkages between the lignin and carbohydrate, which was indicated by a reduction in the peak intensities in the bonds from 1648 cm(-1) to 1516 cm(-1). After pretreatment, the crystallinity index of the rice straw in the 10 bar-10 min cycle with no moisture and 15 bar-10 min cycle with 70% moisture increased from 22.9% to 28.3% and 28.6%, respectively. Steam explosion efficiently decreased the lignin. The highest reduction in the amount of lignin was observed with the 10 bar-10 min cycle, which reached from 18.6% to 13.0%. The methane yield increased with the cycles 10 bar-10 min and 15 bar-15 min with 35% moisture, and 15 bar-10 min with 70% moisture by 113%, 104%, and 147% compared to that of the untreated straw, respectively. Moreover, the highest biodegradation percent of the rice straw was obtained in these cycles.

  • 21.
    Aslanzadeh, S.
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Rajendran, K.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Taherzadeh, M.J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    A comparative study between single- and two-stage anaerobic digestion processes: Effects of organic loading rate and hydraulic retention time2014Ingår i: International Biodeterioration & Biodegradation, ISSN 0964-8305, E-ISSN 1879-0208, Vol. 95, s. 181-188Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effect of an organic loading rate (OLR) and a hydraulic retention time (HRT) was evaluated by comparing the single-stage and two-stage anaerobic digestion processes. Wastes from the food processing industry (FPW) and the organic fraction of the municipal solid waste (OFMSW) were used as substrates. The OLR was increased at each step from 2 gVS/l/d to 14 gVS/l/d, and the HRT was decreased from 10 days to 3 days. The highest theoretical methane yield achieved in the single-stage process was about 84% for the FPW during an OLR of 3 gVS/l/d at a HRT of 7 days and 67% for the OFMSW at an OLR of 2 gVS/l/d and a HRT of 10 days. The single-stage process could not handle a further increase in the OLR and a decrease in the HRT; thus, the process was stopped. A more stable operation was observed at higher OLRs and lower HRTs in the two-stage system. The OLR could be increased to 8 gVS/l/d for the FPW and to 12 gVS/l/d for the OFMSW, operating at a HRT of 3 days. The results show a conclusion of 26% and 65% less reactor volume for the two-stage process compared to the single-stage process for the FPW and the OFMSW, respectively.

  • 22.
    Aslanzadeh, Solmaz
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Pretreatment of cellulosic waste and high rate biogas production2014Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The application of anaerobic digestion technology is growing worldwide, mainly because of its environmental benefits. Nevertheless, anaerobic degradation is a rather slow and sensitive process. One of the reasons is the recalcitrance nature of certain fractions of the substrate (e.g., lignocelluloses) used for microbial degradation; thus, the hydrolysis becomes the rate-limiting step. The other reason is that the degradation of organic matter is based on a highly dynamic, multi-step process of physicochemical and biochemical reactions. The reactions take place in a sequential and parallel way under symbiotic interrelation of a variety of anaerobic microorganisms, which all together make the process sensitive. The first stage of the decomposition of the organic matter is performed by fast growing (hydrolytic and acid forming) microorganisms, while in the second stage the organic acids produced are metabolized by the slow growing methanogens, which are more sensitive than the acidogens; thus, methanogenesis becomes the rate-limiting step. The first part of this work evaluates the effects of a pretreatment using an organic solvent, N-methylmorpholine-N-oxide (NMMO), on cellulose-based materials in order to overcome the challenge of biomass recalcitrance and to increase the rate of the hydrolysis. NMMO-pretreatment of straw separated from the cattle and horse manure resulted in increased methane yields, by 53% and 51%, respectively, in batch digestion tests. The same kind of pretreatment of the forest residues led to an increase by 141% in the methane production during the following batch digestion assays. The second part of this work evaluates the efficacy of a two-stage process to overcome the second challenge with methanogenesis as the rate-limiting step, by using CSTR (continuous stirred tank reactors) and UASB (up flow anaerobic sludge blanket) on a wide variety of different waste fractions in order to decrease the time needed for the digestion process. In the two-stage semi-continuous process, the NMMO-pretreatment of jeans increased the biogas yield due to a more efficient hydrolysis compared to that of the untreated jeans. The results indicated that a higher organic loading rate (OLR) and a lower retention time could be achieved if the material was easily degradable. Comparing the two-stage and the single-stage process, treating the municipal solid waste (MSW) and waste from several food processing industries (FPW), showed that the OLR could be increased from 2 gVS/l/d to 10 gVS/l /d, and at the same time the HRT could be decreased from 10 to 3 days, which is a significant improvement that could be beneficial from an industrial point of view. The conventional single stage, on the other hand, could only handle an OLR of 3 gVS/l/d and HRT of 7 days.

  • 23.
    Aslanzadeh, Solmaz
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Berg, Andreas
    Taherzadeh, Mohammad J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Sárvári Horváth, Ilona
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Biogas Production from N-Methylmorpholine-N-oxide (NMMO) Pretreated Forest Residues2014Ingår i: Applied Biochemistry and Biotechnology, ISSN 0273-2289, E-ISSN 1559-0291, Vol. 172, nr 6, s. 2998-3008Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Lignocellulosic biomass represents a great potential for biogas production. However, a suitable pretreatment is needed to improve their digestibility. This study investigates the effects of an organic solvent, N-Methylmorpholine-N-oxide (NMMO) at temperatures of 120 and 90 °C, NMMO concentrations of 75 and 85 % and treatment times of 3 and 15 h on the methane yield. The long-term effects of the treatment were determined by a semicontinuous experiment. The best results were obtained using 75 % NMMO at 120 °C for 15 h, resulting in 141 % increase in the methane production. These conditions led to a decrease by 9 % and an increase by 8 % in the lignin and in the carbohydrate content, respectively. During the continuous digestion experiments, a specific biogas production rate of 92 NmL/gVS/day was achieved while the corresponding rate from the untreated sample was 53 NmL/gVS/day. The operation conditions were set at 4.4 gVS/L/day organic loading rate (OLR) and hydraulic retention time (HRT) of 20 days in both cases. NMMO pretreatment has substantially improved the digestibility of forest residues. The present study shows the possibilities of this pretreatment method; however, an economic and technical assessment of its industrial use needs to be performed in the future.

  • 24. Aslanzadeh, Solmaz
    et al.
    Ishola, Mofoluwake M.
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Richards, Tobias
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    An Overview of Existing Individual Unit Operations2014Ingår i: Biorefineries: Integrated Biochemical Processes for Liquid Biofuels, Elsevier Inc. , 2014Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    BACKGROUND: Because of its extreme toxicity for microorganisms, the limonene content of citrus wastes (CWs) has been a major obstacle to the conversion of CWs to biofuels. The main objective of this study was to develop a new process for the utilization of CWs that can be economically feasible when the supply of CW is low.

    RESULTS: Steam explosion pre-treatment was applied to improve the anaerobic digestibility of CWs, resulting in a decrease of initial limonene concentration by 94.3%. A methane potential of 0.537 ± 0.001 m 3 kg -1 VS (volatile solids) was obtained during the following batch digestion of treated CWs, corresponding to an increase of 426% compared with that of the untreated samples. Long-term effects of the treatment were further investigated by a semi-continuous co-digestion process. A methane production of 0.555 ± 0.0159 m 3 CH 4 kg -1 VS day -1 was achieved when treated CWs (corresponding to 30% of the VS load) were co-digested with municipal solid waste.

    CONCLUSION: The process developed can easily be applied to an existing biogas plant. The equipment cost for this process is estimated to be one million USD when utilizing 10 000 tons CWs year -1. 8.4 L limonene and 107.4 m 3 methane can be produced per ton of fresh citrus wastes in this manner. 

  • 25.
    Aslanzadeh, Solmaz
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Rajendran, Karthik
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Jeihanipour, Azam
    Taherzadeh, Mohammad J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Waste textile processing into biogas using two-stage reactors2013Konferensbidrag (Övrigt vetenskapligt)
  • 26.
    Aslanzadeh, Solmaz
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Rajendran, Karthik
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Taherzadeh, Mohammad J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    A comparative study between conventional and two stage anaerobic process: Effect of organic loading rate and hydraulic retention time2013Ingår i: / [ed] Shu Li, Jegatheesan Veeriah, Keir Greg, Kier Merrin, Chang Chia-Yuan, CESE 2013 , 2013Konferensbidrag (Refereegranskat)
  • 27.
    Aslanzadeh, Solmaz
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Rajendran, Karthik
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Taherzadeh, Mohammad J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Pretreatment of Lignocelluloses for Biogas and Ethanol Processes2014Ingår i: Advances in Industrial Biotechnology / [ed] Ram Sarup Singh, Ashok Pandey, Christian Larroche, Asiatech Publishers Inc , 2014, s. 125-150Kapitel i bok, del av antologi (Refereegranskat)
  • 28.
    Aslanzadeh, Solmaz
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Rajendran, Karthik
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Taherzadeh, Mohammad J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Pretreatment of lignocelluloses for biogas and ethanol processes2013Ingår i: Advances in Industrial Biotechnology / [ed] Ram Sarup Singh, Ashok Pandey, Christian Larroche, I. K. International Publishing House , 2013, s. 125-150Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 29.
    Aslanzadeh, Solmaz
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Sárvári Horváth, Ilona
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Pretreatment of straw fraction of manure for improved biogas production2011Ingår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 6, nr 4, s. 5193-5205Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Pretreatment of straw separated from cattle and horse manure using N-methylmorpholine oxide (NMMO) was investigated. The pretreatment conditions were for 5 h and 15 h at 120 °C, and the effects were evaluated by batch digestion assays. Untreated cattle and horse manure, both mixed with straw, resulted in 0.250 and 0.279 Nm3 CH4/kgVS (volatile solids), respectively. Pretreatment with NMMO improved both the methane yield and the degradation rate of these substrates, and the effects were further amplified with more pretreatment time. Pretreatment for 15 h resulted in an increase of methane yield by 53% and 51% for cattle and horse manure, respectively. The specific rate constant, k0, was increased from 0.041 to 0.072 (d-1) for the cattle and from 0.071 to 0.086 (d-1) for the horse manure. Analysis of the pretreated straw shows that the structural lignin content decreased by approximately 10% for both samples and the carbohydrate content increased by 13% for the straw separated from the cattle and by 9% for that separated from the horse manure. The crystallinity of straw samples analyzed by FTIR show a decrease with increased time of NMMO pretreatment.

  • 30.
    Aslanzadeh, Solmaz
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Taherzadeh, Mohammad J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Sárvári Horváth, Ilona
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Pretreatment of straw fraction of manure for improved biogas production2011Ingår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 6, nr 4, s. 5193-5205Artikel i tidskrift (Refereegranskat)
  • 31.
    Astiani, D.
    et al.
    Faculty of Forestry, Universitas Tanjungpura.
    Curran, L. M.
    Burhanuddin,
    Faculty of Forestry, Universitas Tanjungpura.
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Mujiman,
    Lembaga Landscape Livelihood Indonesia Pontianak.
    Hatta, M.
    Faculty of Forestry, Universitas Tanjungpura.
    Pamungkas, W.
    Faculty of Forestry, Universitas Tanjungpura.
    Gusmayanti, Evi
    Lembaga Landscape Livelihood Indonesia Pontianak.
    Fire-Driven Biomass And Peat Carbon Losses And Post-Fire Soil Co2 Emission In A West Kalimantan Peatland Forest2018Ingår i: Journal of Tropical Forest Science, ISSN 0128-1283, Vol. 30, nr 4, s. 570-575Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Indonesian peatland forest is considered a huge sink of tropical carbon and thereby make significant contribution to global terrestrial carbon storage. However, landcover and landuse changes in this ecosystem have incurred a synergistic exposure to drought and wildfires. Deforestation and forest degradation through combustion and decomposition of forest biomass and soil carbon have become global issues because of their greenhouse gas contribution to global climate change. Thus fire-driven carbon losses in these peatlands have increased the need to evaluate the impacts of fire at a landscape scale. In 6-10 week dry periods from January to April 2014 and in January 2015, wildfires burnt peatland forest in Kubu Raya, West Kalimantan province (Indonesian Borneo). An assessment was conducted to provide more reliable estimates of the effects of fire on aboveground and soil carbon losses and their dynamics in the coastal peatlands of the province. Carbon loss from combustion of both aboveground biomass and peat soil was substantial. Moreover, CO2 emission from soil respiration at the burnt peat surface increased 46% over the first 9 months after the fire. This study clearly showed the magnitude of fire-driven carbon loss and the scale of CO2 emission to the atmosphere arising from fire in tropical peatland forest.

  • 32.
    Astiani, D
    et al.
    Faculty of Forestry, Universitas Tanjungpura.
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Gusmayanti, E
    Faculty of Agriculture, Universita Tanjungpura.
    Widiastuti, T
    Faculty of Forestry, Universitas Tanjungpura.
    Burhanuddin,
    Faculty of Forestry, Universitas Tanjungpura.
    Local knowledge on landscape sustainable-hydrological management reduces soil co2 emission, fire risk and biomass loss in west Kalimantan Peatland, Indonesia2019Ingår i: Biodiversitas, ISSN 1412-033X, E-ISSN 2085-4722, Vol. 20, nr 3Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Astiani D, TaherzadehMJ, Gusmayanti E, WidiastutiT, Burhanuddin.2019. Local knowledge on landscape sustainable-hydrological management reduces soil CO2 emission, fire risk and biomass loss in West Kalimantan Peatland, Indonesia.Biodiversitas 20:725-731.Local knowledge in managing peatlands, especially in the area of peat hydrology, has been practiced through generations to manage peatlands for agriculture and small scale gardens. Farmers in West Kalimantan have developed the way to conserve water by making simple dams using soil or woody plants to hold water from the peat upstream areas on small channels or rivers. To reduce puddles during rain or tides, people make small trenches, so-called parit cacingin the middle of the larger channel. The trench cross-section size is ~30-40 cm2. This channel can maintain the peat waterlevel to the extent of the depth of the channel. These channels, at the same time, are useful, for a clear, easy land ownership border for one farmer family land. The results of COemissions assessment at various water levels on the peatland landscape demonstrate that the landscape which surrounded by the parit cacingtrenches can maintain lower CO2 emissions compared to the one that has deeper water levels. The knowledge to develop this channel has also reduced the risk of peatland fire hazard and the amount of peat biomass loss on a fire event. An assessment on the effect of water level on the loss of peat biomass when burned, reduce 30-78% loss risks if compared to water table depth of 60-80cm, which is assumed as general practices on peatland recently.The practices of the knowledge on peatlands hydrology management can reduce the risk of peatland soil CO2 emission as well as loss of peat mass through decomposition and during peat fires.

  • 33.
    Barghi, H.
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Taherzadeh, M.J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Synthesis of an electroconductive membrane using poly(hydroxymethyl-3,4-ethylenedioxythiophene-co-tetramethylene-N-hydroxyethyl adipamide)2013Ingår i: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 1, nr 39, s. 6347-6354Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Synthesis of a novel electroconductive membrane (ECM) was studied with the aim of producing an electroconductive membrane (ECM) with low electrical resistance and appropriate mechanical properties. The method was based on copolymerization of a highly electroconductive monomer (hydroxymethyl-3,4-ethylenedioxythiophene) with highly mechanical resistant hydrophilized polyamide 46 (polytetramethylene-N-hydroxyethyl adipamide). Due to the lack of hydroxyl groups, polyamide 46 does not have the tendency to take part in any chemical reactions, therefore prior to copolymerization, PA 46 was hydrophilized with acetaldehyde to create reactive sites, which allowed copolymerization to occur. At the final stage, a very thin layer, 566 nm conductive poly(hydroxymethyl-3,4-ethylenedioxythiophene) homopolymer was localised using in situ plasma polymerization in order to improve the electrical conductivity of the obtained copolymer. The result was an adherent, highly conductive, semi-hydrophilic and flexible ECM. The presence of hydroxyl groups in the final product led to improved hydrophilicity of the conductive membrane with a surface tension of 41 mJ m−2. The electrical resistance of PA 46 was dramatically reduced after copolymerization, to 202 in dry and 54 kΩ cm−2 in wet conditions; furthermore, after plasma treatment, this reduction continued to 105 in dry and 2 kΩ cm−2 in wet conditions. Other parameters such as flux flow, roughness, pore size, pore distribution, contact angle, surface energy and thermal stability of the ECM were also investigated.

  • 34.
    Barghi, Hamidreza
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Taherzadeh, Mohammad J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Catalytic Synthesis of Bulk Hydrophilic Acetaldehyde-Modified Polyamide 462014Ingår i: Current Organic Synthesis, ISSN 1570-1794, E-ISSN 1875-6271, Vol. 11, nr 6, s. 288-294Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hydrophilization of Polyamide 46 (PA46) via modification with acetaldehyde in continuous phase was studied. The chemical modification of PA 46 with acetaldehyde resulted in a water-swollen polymer with hydrophilic property. The polyamide 46 undergoes a nucleophilic addition with acetaldehyde in the presence of aluminum chloride as a catalyst. The extent of bulk hydroxyethylation using AlCl3 resulted in 95.65% modification counted as total N-hydroxyethylated polyamide 46. The modification resulted in improved hydrophilic properties, and a maximum surface free energy of 44.6 mJ/m2 was achieved after 3 h reaction, whereas the unmodified PA46 had a surface free energy of 11.2 mJ/m2. In addition, thermal properties of the polymers were studied using differential scanning calorimetry and thermogravimetric analyses. The functionalization leads to decrease in the crystallization energy from 88 J/g to 51 J/g, while the melting energy is changed from 110 J/g to 53 J/g. Furthermore, the thermal stability of the PA46 to pyrolysis was diminished after hydroxylation.

  • 35.
    Barghi, Hamidreza
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Taherzadeh, Mohammad J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Synthesis and characterization of novel bulk hydrophilic acetaldehyde modified polyamide 462011Konferensbidrag (Övrigt vetenskapligt)
  • 36. Beigi, H.M.
    et al.
    Karimi, Keikhosro
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Effects of temperature, pH and glucose concentration on bioethanol production by Mucor indicus2009Konferensbidrag (Övrigt vetenskapligt)
  • 37. Bhaskar, Thallada
    et al.
    Lee, Keat Teong
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Sauer, Michael
    Nampoothiri, K. Madhavan
    New Horizons in Biotechnology - NHBT 20152016Ingår i: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 213Artikel i tidskrift (Refereegranskat)
  • 38. Bidgoli, H.
    et al.
    Zamani, A.
    Jeihanipour, A.
    Taherzadeh, M.J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Preparation of carboxymethyl cellulose superabsorbents from waste textiles Fibers and Polymers2014Ingår i: Fibers And Polymers, ISSN 1229-9197, E-ISSN 1875-0052, Vol. 15, nr 3, s. 431-436Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Production of superabsorbent polymers from cotton and viscose waste textiles was investigated. The cellulose wastes were carboxymethylated, crosslinked by divinylsulfone, and then converted to superabsorbent material using air-drying, freeze-drying, or air-drying after phase inversion. The separation of cellulose from synthetic polymers in the textile (polyester) was carried out by direct dissolution of cellulose in N-methylmorpholine-N-oxide (NMMO), or separation by dissolution in water after carboxymethylation of the textiles. The progress of the carboxymethylation reaction was evaluated by measurement of the degree of substitution (DS) of carboxymethyl cellulose (CMC). The DS values of 0.50–0.86 confirmed the prosperous substitution of hydrophilic carboxymethyl groups into the cellulosic chains. The water binding capacity and the swelling rate of the superabsorbents prepared under different conditions were measured. Under the best condition the superabsorbent obtained from waste textiles showed an ultimate water binding capacity of 541 g/g which was notably higher than that of the reference superabsorbent derived from cotton linter (470 g/g). The amount of absorbed water by this product exceeded that of the reference sample after 60 min immersion.

  • 39. Bidgoli, Hossein
    et al.
    Zamani, Akram
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Taherzadeh, Mohammad J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Effect of carboxymethylation conditions on water binding capacity of chitosan-based superabsorbents2010Ingår i: Carbohydrate Research, ISSN 0008-6215, E-ISSN 1873-426X, Vol. 345, nr 18, s. 2683-2689Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A superabsorbent polymer (SAP) from chitosan was provided via carboxymethylation of chitosan, followed by cross-linking with glutaraldehyde and freeze-drying. This work was focused on an investigation of the effects of monochloroacetic acid (MCAA), sodium hydroxide, and reaction time on preparation of carboxymethylchitosan (CMCS). The CMCS products were characterized using FTIR spectroscopy, and their degrees of substitution (DS) were measured using conductimetry and FTIR analysis. The highest DS value was obtained when the carboxymethylation reaction was carried out using 1.75 g MCAA and 1.75 g NaOH per g of chitosan in 4 h. The water solubilities of the CMCS products at various pHs were also evaluated, and the results indicated a significant impact of the reaction parameters on the solubility of CMCS. The CMCSs with the highest DS value resulted in SAPs having the highest water-binding capacity (WBC). TheWBCof the best SAP measured after 10 minexposure in distilled water, 0.9% NaCl solution, synthetic urine, and artificial blood was 104, 33, 30, and 57 g/g, respectively. The WBC of this SAP at pH 2–9 passed a maximum at pH 6.

  • 40. Billig, S.
    et al.
    Agrawal, P.B.
    Birkemeyer, C.
    Nierstrasz, Vincent
    Högskolan i Borås, Institutionen Textilhögskolan.
    Warmoeskerken, M.M.C.G.
    Zimmerman, W.
    Biodegradation of diverse PET materials by polyester hydrolases from Thermobifida fusca and Fusarium solani2014Konferensbidrag (Refereegranskat)
  • 41. Bátori, Veronika
    et al.
    Ferreira, Jorge A
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Lennartsson, Patrik R
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Ethanol and Protein from Ethanol Plant By-Products Using Edible Fungi Neurospora intermedia and Aspergillus oryzae2015Ingår i: BioMed Research International, ISSN 2314-6133, E-ISSN 2314-6141, Vol. 2015, nr nov23Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Feasible biorefineries for production of second-generation ethanol are difficult to establish due to the process complexity. An alternative is to partially include the process in the first-generation plants. Whole stillage, a by-product from dry-mill ethanol processes from grains, is mostly composed of undegraded bran and lignocelluloses can be used as a potential substrate for production of ethanol and feed proteins. Ethanol production and the proteins from the stillage were investigated using the edible fungi Neurospora intermedia and Aspergillus oryzae, respectively. N. intermedia produced 4.7 g/L ethanol from the stillage and increased to 8.7 g/L by adding 1 FPU of cellulase/g suspended solids. Saccharomyces cerevisiae produced 0.4 and 5.1 g/L ethanol, respectively. Under a two-stage cultivation with both fungi, up to 7.6 g/L of ethanol and 5.8 g/L of biomass containing 42% (w/w) crude protein were obtained. Both fungi degraded complex substrates including arabinan, glucan, mannan, and xylan where reductions of 91, 73, 38, and 89% (w/v) were achieved, respectively. The inclusion of the current process can lead to the production of 44,000 m(3) of ethanol (22% improvement), around 12,000 tons of protein-rich biomass for animal feed, and energy savings considering a typical facility producing 200,000 m(3) ethanol/year.

  • 42.
    Bátori, Veronika
    et al.
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Lundin, Magnus
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Åkesson, Dan
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Lennartsson, Patrik R.
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Zamani, Akram
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    The effect of glycerol, sugar and maleic anhydride on pectin-cellulose biofilms prepared from orange wasteIngår i: Artikel i tidskrift (Refereegranskat)
  • 43.
    Bátori, Veronika
    et al.
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Lundin, Magnus
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Åkesson, Dan
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Lennartsson, Patrik R.
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Zamani, Akram
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    The Effect of Glycerol, Sugar, and Maleic Anhydride on Pectin-Cellulose Thin Films Prepared from Orange Waste2019Ingår i: POLYMERS, Vol. 11, nr 3Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study was conducted to improve the properties of thin films prepared from orange waste by the solution casting method. The main focus was the elimination of holes in the film structure by establishing better cohesion between the major cellulosic and pectin fractions. For this, a previously developed method was improved first by the addition of sugar to promote pectin gelling, then by the addition of maleic anhydride. Principally, maleic anhydride was introduced to the films to induce cross-linking within the film structure. The effects of concentrations of sugar and glycerol as plasticizers and maleic anhydride as a cross-linking agent on the film characteristics were studied. Maleic anhydride improved the structure, resulting in a uniform film, and morphology studies showed better adhesion between components. However, it did not act as a cross-linking agent, but rather as a compatibilizer. The middle level (0.78%) of maleic anhydride content resulted in the highest tensile strength (26.65 +/- 3.20 MPa) at low (7%) glycerol and high (14%) sugar levels and the highest elongation (28.48% +/- 4.34%) at high sugar and glycerol levels. To achieve a uniform film surface with no holes present, only the lowest (0.39%) level of maleic anhydride was necessary.

  • 44. Cabrera-Rodríquez, Emir
    et al.
    Curbelo-Hernández, Caridad
    Karimi, Keikhosro
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Taherzadeh, Mohammad J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Effect of sodium hydroxide pretreatment at low temperature on chemical composition and enzymatic hydrolysis of spruce2013Ingår i: Revista CENIC Ciencias Químicas, ISSN 2221-2442, Vol. 43, nr 1, s. 1-9Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The availability of fermentable sugars is a limiting factor for large-scale production of biological products such as bioethanol. Therefore, processes to produce sugars are being developed from lignocellulosic materials by enzymatic hydrolysis. However, the cellulose fraction are not readily accessible for the hydrolyzing enzymes and an efficient hydrolysis requires pretreatment. Several processes have been investigated for this pretreatment. Pretreatment of lignocelluloses with NaOH is among the promissing methods. In the present work, the effect of NaOH pretreatment at low temperature on chemical composition and subsequent enzymatic hydrolysis of spruce was investigated. A native spruce specie obtained from the forest around Borås city in Sweden was used in an the experiments. This wood was analyzed for carbohydrate and lignin fractions according to NREL methods. The wood was chemically pretreated using 7 % (w/w) sodium hydroxide solution with 5 % (w/v) solid content at 0 °C for 0.5, 1, 2 and 3 h. Commercial enzymes, cellulase (Celluclast 1.5 L, Novozyme, Denmark) and β-glucosidase (Novozyme 188, Novozyme, Denmark) were used in the enzymatic hydrolysis with activities of 30 FPU and 50 IU per gram of wood, respectively. The pretreatments changed the material composition. It was a very low loss of carbohydrate, about 98 % recovery, suggesting no significant carbohydrate hydrolysis. Xylans were the most affected by the pretreatments. The largest xylan removal was almost 50 %, using sodium hydroxide solution for 3 h. The profile of released sugars were also analyzed and compared. An improvement of enzymatic hydrolysis yield was observed as a result of the applied pretreatments, near 40 % glucose yield could be achieved.

  • 45. Cahyari, Khamdan
    et al.
    Syamsiah, Siti
    Sarto,
    Taherzadeh, Mohammad J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Harvesting biohydrogen (BioH2) and biomethane (BioCH4) from fruit waste through sequential thermophilic fermentation2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    A sequential two stages thermophilic fermentation of fruit waste i.e. orange, banana, apple, grape, melon to produce biofuels i.e. biohydrogen (BioH2) and biomethane (BioCH4) was investigated. In the first stage, fermentative BioH2 from each waste was successfully carried out without any methane being detected. Among the wastes, apple generated more gas with cumulative BioH2 yield (CHY) as 19.91 mmol/g VS (90% of theoretical value), while the lowest one resulted from melon (8.14 mmol/g VS or 36.8%). In the second stage, fermentative BioCH4 of residual liquid from the first stage was achieved successfully for banana, VEMF, apple, grape, melon, and orange with the cumulative BioCH4 yield (CHY) as 10.62, 14.23, 15.88, 16.26, 16.74, and 18.50 mmol CH4/g VSadded respectively. It was also showed from chemical oxygen demand (COD) measurement that COD removal efficiency achieved significantly high from 48% up to 60% for all the waste except orange which was only 16.7%. It was presumed that orange contained difficult-to-degrade materials such as limonene. In fact, fermentative BioH2 of orange in higher limonene concentration at 18 mg/l was totally inhibited. A simulation of potential generated energy (PGE) from the fruits waste being treated through this method was carried out based on the quantity of worldwide harvested fruits in 2009 (FAO UN), in consideration that 10% of the fruits were wasted. It is surprisingly understood that each of the fruits waste can deliver more than 64 MWh of electricity.

  • 46. Carrillo Nieves, Danay
    et al.
    Karimi, Keikhosro
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Sárvári Horvátha, Ilona
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Improvement of biogas production from oil palm empty fruit bunches (OPEFB)2011Ingår i: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, Vol. 34, nr 1, s. 1097-1101Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Oil palm empty fruit bunches (OPEFB), a waste lignocellulosic material, which is the main byproduct of vegetable oil production industries in Indonesia and Malaysia, was utilized as a source for biogas production. Pretreatments using NaOH as well as phosphoric acid were investigated to improve the biogas production. Clear positive effects of the pretreatments on the yield of methane were observed. The best improvement was achieved when 8% NaOH for 60 min was used for the pretreatment, which resulted in 100% improvement in the yield of methane production. In addition, treatment with phosphoric acid resulted in 40% improvement in the methane yield compared with that of the untreated material. The results showed that the carbohydrate content of OPEFB could be efficiently converted to methane under the anaerobic digestion process. 97% of the theoretical value of methane production was achieved after the pretreatment with NaOH for 60 min. Moreover, the initial rate of methane production was also increased by more than 85% after the treatment with NaOH compared with that of the untreated OPEFB.

  • 47.
    Chandolias, Konstantinos
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Lignocellulosic Biorefinery for Biohydrogen and Carboxylic Acids Production in Flexible Membrane Bioreactor and Two-stage System2017Ingår i: 7th Nordic Wood Biorefinery Conference. 28-30 March 2017. Stockholm, 2017Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Lignocellulosic biorefineries can produce numerous biofuels and chemicals via the anaerobic digestion process. Although several works have been recently conducted on this field, the technology is considered new and more research efforts are required towards industrialisation. In this work, wheat straw was digested after hydrolysis with dilute phosphoric acid. The substrate was biologically converted into carboxylic acids and biohydrogen at different OLRs (4.42-17.95 g COD/L.d). The semi-continuous experiments took place at 55 °C, both in reactors with free-cells or mixed free and membrane-encased cells, According to the results, the optimum biohydrogen, acetic and isobutyric acid yields were obtained at OLR of 4.42 g COD/L.d. Moreover, the highest lactic acid production was recorded at OLR of 9.33 g COD/L.d. Furthermore, a reactor containing both free and membrane-encased cells showed 60% higher lactic acid production (at OLR of 13.42 g COD/L.d) in comparison to the conventional free cell reactor. In addition, the production of acetic and isobutyric acid was greatly improved by a two-stage system. The use of both free and encased cells in a flexible membrane system along with the two-stage system for the optimisation of the process is the main novelty of this work.

  • 48.
    Chandolias, Konstantinos
    et al.
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Pekgenc, Enise
    Department of Environmental Engineering, Istanbul Technical University.
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Floating membrane bioreactors with high gas hold-up for syngas-to-biomethane conversion2019Ingår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 12, nr 6Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The low gas-to-liquid mass transfer rate is one of the main challenges in syngas biomethanation. In this work, a new concept of the floating membrane system with high gas hold-up was introduced in order to enhance the mass transfer rate of the process. In addition, the effect of the inoculum-to-syngas ratio was investigated. The experiments were conducted at 55 °C with an anaerobic mixed culture in both batch and continuous modes. According to the results from the continuous experiments, the H2 and CO conversion rates in the floating membrane bioreactor were approximately 38% and 28% higher in comparison to the free (suspended) cell bioreactors. The doubling of the thickness of the membrane bed resulted in an increase of the conversion rates of H2 and CO by approximately 6% and 12%, respectively. The highest H2 and CO consumption rates and CH4 production rate recorded were approximately 22 mmol/(L·d), 50 mmol/(L·d), and 34.41 mmol/(L·d), respectively, obtained at the highest inoculum-to-syngas ratio of 0.2 g/mL. To conclude, the use of the floating membrane system enhanced the syngas biomethanation rates, while a thicker membrane bed resulted in even higher syngas conversion rates. Moreover, the increase of the inoculum-to-syngas ratio of up to 0.2 g/mL favored the syngas conversion.

  • 49.
    Chandolias, Konstantinos
    et al.
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Wainaina, Steven
    Niklasson, Claes
    Chalmers Technical University.
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Effects of Heavy Metals and pH on the Conversion of Biomass to Hydrogen via Syngas Fermentation2018Ingår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effects of three heavy metals on hydrogen production via syngas fermentation were investigated within a metal concentration range of 0-1.5 mg Cu/L, 0-9 mg Zn/L, 0-42 mg Mn/L, in media with initial pH of 5, 6 and 7, at 55 °C. The results showed that at lower metal concentration, pH 6 was optimum while at higher metal concentrations, pH 5 stimulated the process. More specifically, the highest hydrogen production activity recorded was 155.28% ± 12.02% at a metal concentration of 0.04 mg Cu/L, 0.25 mg Zn/L, and 1.06 mg Mn/L and an initial medium pH of 6. At higher metal concentration (0.625 mg Cu/L, 3.75 mg Zn/L, and 17.5 mg Mn/L), only pH 5 was stimulating for the cells. The results show that the addition of heavy metals, contained in gasification-derived ash, can improve the production rate and yield of fermentative hydrogen. This could lead in lower costs in gasification process and fermentative hydrogen production and less demand for syngas cleaning before syngas fermentation.

  • 50.
    Chandolias, Konstantinos
    et al.
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Youngsukkasem, Supansa
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Taherzadeh, Mohammad
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Rapid Bio-methanation of Syngas by High Cell-density in Reverse Membrane Bioreactor (RMBR)2015Ingår i: Advanced Membrane Technology VI: Water, Energy and New Frontiers / [ed] Dibakar Bhattacharyya (University of Kentucky, USA), Benny Freeman (University of Texas, USA), 2015Konferensbidrag (Övrigt vetenskapligt)
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