Change search
Refine search result
1234567 1 - 50 of 332
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1. Abbaszadeh, A
    et al.
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Effect of extraction conditions on yield and purity of citrus pectin by sulfuric and hydrochloric acids2009Conference paper (Refereed)
  • 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
    University of Borås, Faculty of Textiles, Engineering and Business.
    Ethanol production by Mucor indicus and Rhizopus oryzae from rice straw by separate hydrolysis and fermentation2009In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 33, no 5, p. 828-833Article in journal (Refereed)
    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
    University of Borås, School of Engineering.
    Khanahmadi, Morteza
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Ethanol production by Mucor indicus and Rhizapus oryzae from rice straw by separate hydrolysis and fermentation2009In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 33, no 5, p. 828-833Article in journal (Refereed)
    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.
    University of Borås, School of Engineering.
    Ethanol production by Mucor indicus at high glucose and ethanol concentrations2010In: Minerva biotecnologica (Testo stampato), ISSN 1120-4826, E-ISSN 1827-160X, Vol. 22, no 3-4, p. 83-89Article in journal (Refereed)
    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.
    University of Borås, School of Engineering.
    Ketzscher, Richard
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    High performance natural fibre hybrid composites based on biobased thermoset resins for use in technical applications2009Conference paper (Other academic)
    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.
    University of Borås, School of Engineering.
    Åkesson, Dan
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Synthesis of reactive soybean oils for use as a biobased thermoset resins in structural natural fiber composites2009In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 115, no 6, p. 3137-3145Article in journal (Refereed)
    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
    University of Borås, Faculty of Textiles, Engineering and Business.
    Rhamnolipid as new bio-agent for cleaning of ultrafiltration membrane fouled by whey2018In: Engineering in Life Sciences, ISSN 1618-0240, E-ISSN 1618-2863, Vol. 18, no 5, p. 272-280Article in journal (Refereed)
    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.
    University of Borås, Swedish School of Textiles.
    Nierstrasz, Vincent
    University of Borås, Swedish School of Textiles.
    Perwuelz, A.
    Guan, J.P.
    Chen, G.Q.
    Eco-design innovative methods for fabric finishing2014Conference paper (Other academic)
  • 9.
    Ahlström, Peter
    et al.
    University of Borås, School of Engineering.
    Gebäck, Tobias
    University of Borås, School of Engineering.
    Johansson, Erik
    University of Borås, School of Engineering.
    Bolton, Kim
    University of Borås, School of Engineering.
    Water absorption in polymers2010Conference paper (Other academic)
    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
    University of Borås, School of Engineering.
    Lundin, M
    University of Borås, School of Engineering.
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Optimization of baker's yeast drying in industrial continuous fluidized-bed dryer2012In: Food and Bioproducts Processing, ISSN 0960-3085, E-ISSN 1744-3571, Vol. 90, no 1, p. 52-57Article in journal (Refereed)
    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.
    University of Borås, School of Engineering.
    Brandberg, Tomas
    University of Borås, School of Engineering.
    Sanni, Sikiru A.
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Development and Dissemination Strategies for Accelerating Biogas Production in Nigeria2014In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 9, no 3Article in journal (Refereed)
    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.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Evaluation of Fermentative Hydrogen Production from Single and Mixed Fruit Wastes2015In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 8, no 5, p. 4253-4272Article in journal (Refereed)
    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.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Wikandari, Rachman
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Enhanced Fermentative Hydrogen and Methane Production from an Inhibitory Fruit-Flavored Medium with Membrane-Encapsulated Cells.2015In: Membranes, ISSN 2077-0375, E-ISSN 2077-0375, Vol. 5, no 4Article in journal (Refereed)
    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
    University of Borås, School of Engineering.
    Feuk-Lagerstedt, Elisabeth
    University of Borås, School of Engineering.
    Sárvári Horváth, Ilona
    University of Borås, School of Engineering.
    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 production2009Conference paper (Other academic)
    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
    University of Borås, Faculty of Textiles, Engineering and Business.
    Rapid biodegradation of methyl tert-butyl ether (MTBE) by pure bacterial cultures2007In: Iranian Journal of Chemistry and Chemical Engineering, ISSN 1021-9986, Vol. 26, no 1, p. 1-7Article in journal (Refereed)
    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
    University of Borås, Faculty of Textiles, Engineering and Business.
    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 landfill2017In: International Journal of Technology, ISSN 2086-9614, Vol. 8, no 8, p. 1385-1392Article in journal (Refereed)
    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.
    University of Borås, School of Engineering.
    Taherzadeh, M.J.
    University of Borås, School of Engineering.
    Fungal autolysate as a nutrient supplement for ethanol and chitosan production by Mucor indicus2011In: Biotechnology letters, ISSN 0141-5492, E-ISSN 1573-6776, Vol. 33, no 12, p. 2405-2409Article in journal (Refereed)
    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.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Using spent sulfite liquor for valuable fungal biomass production by Aspergilus oryzae2017In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 32, no 4, p. 630-638Article in journal (Refereed)
    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.
    Aslanzadeh, S.
    et al.
    University of Borås, School of Engineering.
    Rajendran, K.
    University of Borås, School of Engineering.
    Taherzadeh, M.J.
    University of Borås, School of Engineering.
    A comparative study between single- and two-stage anaerobic digestion processes: Effects of organic loading rate and hydraulic retention time2014In: International Biodeterioration & Biodegradation, ISSN 0964-8305, E-ISSN 1879-0208, Vol. 95, p. 181-188Article in journal (Refereed)
    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.

  • 20.
    Aslanzadeh, Solmaz
    University of Borås, School of Engineering.
    Pretreatment of cellulosic waste and high rate biogas production2014Doctoral thesis, comprehensive summary (Other academic)
    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.

  • 21.
    Aslanzadeh, Solmaz
    et al.
    University of Borås, School of Engineering.
    Berg, Andreas
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Sárvári Horváth, Ilona
    University of Borås, School of Engineering.
    Biogas Production from N-Methylmorpholine-N-oxide (NMMO) Pretreated Forest Residues2014In: Applied Biochemistry and Biotechnology, ISSN 0273-2289, E-ISSN 1559-0291, Vol. 172, no 6, p. 2998-3008Article in journal (Refereed)
    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.

  • 22. Aslanzadeh, Solmaz
    et al.
    Ishola, Mofoluwake M.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Richards, Tobias
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    An Overview of Existing Individual Unit Operations2014In: Biorefineries: Integrated Biochemical Processes for Liquid Biofuels, Elsevier Inc. , 2014Chapter in book (Refereed)
    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. 

  • 23.
    Aslanzadeh, Solmaz
    et al.
    University of Borås, School of Engineering.
    Rajendran, Karthik
    University of Borås, School of Engineering.
    Jeihanipour, Azam
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Waste textile processing into biogas using two-stage reactors2013Conference paper (Other academic)
  • 24.
    Aslanzadeh, Solmaz
    et al.
    University of Borås, School of Engineering.
    Rajendran, Karthik
    University of Borås, School of Engineering.
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    A comparative study between conventional and two stage anaerobic process: Effect of organic loading rate and hydraulic retention time2013In: / [ed] Shu Li, Jegatheesan Veeriah, Keir Greg, Kier Merrin, Chang Chia-Yuan, CESE 2013 , 2013Conference paper (Refereed)
  • 25.
    Aslanzadeh, Solmaz
    et al.
    University of Borås, School of Engineering.
    Rajendran, Karthik
    University of Borås, School of Engineering.
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Pretreatment of Lignocelluloses for Biogas and Ethanol Processes2014In: Advances in Industrial Biotechnology / [ed] Ram Sarup Singh, Ashok Pandey, Christian Larroche, Asiatech Publishers Inc , 2014, p. 125-150Chapter in book (Refereed)
  • 26.
    Aslanzadeh, Solmaz
    et al.
    University of Borås, School of Engineering.
    Rajendran, Karthik
    University of Borås, School of Engineering.
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Pretreatment of lignocelluloses for biogas and ethanol processes2013In: Advances in Industrial Biotechnology / [ed] Ram Sarup Singh, Ashok Pandey, Christian Larroche, I. K. International Publishing House , 2013, p. 125-150Chapter in book (Other academic)
  • 27.
    Aslanzadeh, Solmaz
    et al.
    University of Borås, School of Engineering.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Sárvári Horváth, Ilona
    University of Borås, Faculty of Textiles, Engineering and Business.
    Pretreatment of straw fraction of manure for improved biogas production2011In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 6, no 4, p. 5193-5205Article in journal (Refereed)
    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.

  • 28.
    Aslanzadeh, Solmaz
    et al.
    University of Borås, School of Engineering.
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Sárvári Horváth, Ilona
    University of Borås, School of Engineering.
    Pretreatment of straw fraction of manure for improved biogas production2011In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 6, no 4, p. 5193-5205Article in journal (Refereed)
  • 29.
    Barghi, H.
    et al.
    University of Borås, School of Engineering.
    Taherzadeh, M.J.
    University of Borås, School of Engineering.
    Synthesis of an electroconductive membrane using poly(hydroxymethyl-3,4-ethylenedioxythiophene-co-tetramethylene-N-hydroxyethyl adipamide)2013In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 1, no 39, p. 6347-6354Article in journal (Refereed)
    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.

  • 30.
    Barghi, Hamidreza
    et al.
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Catalytic Synthesis of Bulk Hydrophilic Acetaldehyde-Modified Polyamide 462014In: Current Organic Synthesis, ISSN 1570-1794, E-ISSN 1875-6271, Vol. 11, no 6, p. 288-294Article in journal (Refereed)
    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.

  • 31.
    Barghi, Hamidreza
    et al.
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Synthesis and characterization of novel bulk hydrophilic acetaldehyde modified polyamide 462011Conference paper (Other academic)
  • 32. Beigi, H.M.
    et al.
    Karimi, Keikhosro
    University of Borås, School of Engineering.
    Effects of temperature, pH and glucose concentration on bioethanol production by Mucor indicus2009Conference paper (Other academic)
  • 33. Bhaskar, Thallada
    et al.
    Lee, Keat Teong
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Sauer, Michael
    Nampoothiri, K. Madhavan
    New Horizons in Biotechnology - NHBT 20152016In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 213Article in journal (Refereed)
  • 34. Bidgoli, H.
    et al.
    Zamani, A.
    Jeihanipour, A.
    Taherzadeh, M.J.
    University of Borås, School of Engineering.
    Preparation of carboxymethyl cellulose superabsorbents from waste textiles Fibers and Polymers2014In: Fibers And Polymers, ISSN 1229-9197, E-ISSN 1875-0052, Vol. 15, no 3, p. 431-436Article in journal (Refereed)
    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.

  • 35. Bidgoli, Hossein
    et al.
    Zamani, Akram
    University of Borås, School of Engineering.
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Effect of carboxymethylation conditions on water binding capacity of chitosan-based superabsorbents2010In: Carbohydrate Research, ISSN 0008-6215, E-ISSN 1873-426X, Vol. 345, no 18, p. 2683-2689Article in journal (Refereed)
    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.

  • 36. Billig, S.
    et al.
    Agrawal, P.B.
    Birkemeyer, C.
    Nierstrasz, Vincent
    University of Borås, Swedish School of Textiles.
    Warmoeskerken, M.M.C.G.
    Zimmerman, W.
    Biodegradation of diverse PET materials by polyester hydrolases from Thermobifida fusca and Fusarium solani2014Conference paper (Refereed)
  • 37. Bátori, Veronika
    et al.
    Ferreira, Jorge A
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Lennartsson, Patrik R
    University of Borås, Faculty of Textiles, Engineering and Business.
    Ethanol and Protein from Ethanol Plant By-Products Using Edible Fungi Neurospora intermedia and Aspergillus oryzae2015In: BioMed Research International, ISSN 2314-6133, E-ISSN 2314-6141, Vol. 2015, no nov23Article in journal (Refereed)
    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.

  • 38. Cabrera-Rodríquez, Emir
    et al.
    Curbelo-Hernández, Caridad
    Karimi, Keikhosro
    University of Borås, School of Engineering.
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Effect of sodium hydroxide pretreatment at low temperature on chemical composition and enzymatic hydrolysis of spruce2013In: Revista CENIC Ciencias Químicas, ISSN 2221-2442, Vol. 43, no 1, p. 1-9Article in journal (Refereed)
    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.

  • 39. Cahyari, Khamdan
    et al.
    Syamsiah, Siti
    Sarto,
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Harvesting biohydrogen (BioH2) and biomethane (BioCH4) from fruit waste through sequential thermophilic fermentation2011Conference paper (Refereed)
    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.

  • 40. Carrillo Nieves, Danay
    et al.
    Karimi, Keikhosro
    University of Borås, School of Engineering.
    Sárvári Horvátha, Ilona
    University of Borås, School of Engineering.
    Improvement of biogas production from oil palm empty fruit bunches (OPEFB)2011In: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, Vol. 34, no 1, p. 1097-1101Article in journal (Refereed)
    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.

  • 41.
    Chandolias, Konstantinos
    University of Borås, Faculty of Textiles, Engineering and Business.
    Lignocellulosic Biorefinery for Biohydrogen and Carboxylic Acids Production in Flexible Membrane Bioreactor and Two-stage System2017In: 7th Nordic Wood Biorefinery Conference. 28-30 March 2017. Stockholm, 2017Conference paper (Other academic)
    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.

  • 42.
    Chandolias, Konstantinos
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Wainaina, Steven
    Niklasson, Claes
    Chalmers Technical University.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Effects of Heavy Metals and pH on the Conversion of Biomass to Hydrogen via Syngas Fermentation2018In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126Article in journal (Refereed)
    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.

  • 43.
    Chandolias, Konstantinos
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Youngsukkasem, Supansa
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad
    University of Borås, Faculty of Textiles, Engineering and Business.
    Rapid Bio-methanation of Syngas by High Cell-density in Reverse Membrane Bioreactor (RMBR)2015In: Advanced Membrane Technology VI: Water, Energy and New Frontiers / [ed] Dibakar Bhattacharyya (University of Kentucky, USA), Benny Freeman (University of Texas, USA), 2015Conference paper (Other academic)
  • 44. Christia, Abdi
    et al.
    Setiowati, Arima Diah
    Millati, Ria
    Karimi, Keikhosro
    University of Borås, Faculty of Textiles, Engineering and Business.
    Cahyanto, Muhammad Nur
    Niklasson, Claes
    Taherzadeh, Mohammad J.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Ethanol production from alkali-pretreated oil palm empty fruit bunch by simultaneous saccharification and fermentation with mucor indicus2016In: International Journal of Green Energy, ISSN 1543-5075, E-ISSN 1543-5083, Vol. 13, no 6, p. 566-572Article in journal (Refereed)
    Abstract [en]

    Oil palm empty fruit bunch (OPEFB) is a potential raw material for production of lignocellulosic bioethanol. The OPEFB was pretreated with 8% sodium hydroxide solution at 100 °C for 10 to 90 min. Enzymatic digestion was carried out using cellulase and β-glucosidase at 45 °C for 24 h. It was then inoculated with Mucor indicus spores suspension and fermented under anaerobic conditions at 37 °C for 96 h. Sodium hydroxide pretreatment effectively removed 51-57% of lignin in the OPEFB and also its hemicellulose (40-84%). The highest glucan digestibility (0.75 g/g theoretical glucose) was achieved in 40 min NaOH pretreatment. Fermentation by M. indicus resulted in 68.4% of the theoretical ethanol yield, while glycerol (16.2-83.2 mg/g), succinic acid (0-0.4 mg/g), and acetic acid (0-0.9 mg/g) were its by-products. According to these results, the 11.75 million tons of dry OPEFB in Indonesia can be converted to 1.5 billion litres of ethanol per year.

  • 45.
    Ciera, L.
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Beladjal, L.
    Almeras, X.
    A model system to study resistance of biological compounds to melt extrusion process parameters.2013In: Proceedings of the 13th AUTEX World Textile Conference, Dresden, Germany May 22-24  2013., 2013, p. 1-6Conference paper (Other academic)
  • 46. Ciera, L
    et al.
    Beladjal, L
    Almeras, X
    Gheysens, T
    Nierstrasz, Vincent
    University of Borås, Swedish School of Textiles.
    Van Langenhove, L
    Mertens, J
    Resistance of Bacillus Amyloliquefaciens spores to melt extrusion process conditions2014In: Fibres & Textiles in Eastern Europe, ISSN 1230-3666, Vol. 22, no 2, p. 102-107Article in journal (Refereed)
    Abstract [en]

    With the increasing demand for functionalised textile materials, industry is focusing on research that will add novel properties to textiles. Bioactive compounds and their benefits have been and are still considered as a possible source of unique functionalities to be explored. However, incorporating bioactive compounds into textiles and their resistance to textile process parameters has not yet been studied. In this study, we developed a system to study the resistance of Bacillus amyloliquefaciens spores against melt extrusion process parameters, like temperature (21, 200, 250, 300 °C), pressure (0.1, 0.6 and 1.0 MPa) and residence time (0, 1 and 10 minutes). The spores were successfully embedded in PET (polyethylene terephthalate) films and fibres through melt extrusion. Afterwards the survival rate of the spores was determined after extrusion and the data was used to develop a quadratic equation that relates the survival rate to the spore concentration.

  • 47. Ciera, L.
    et al.
    Beladjal, L.
    Almeras, X.
    Gheysens, T.
    Van Landuyt, L.
    Mertens, J.
    Nierstrasz, V.
    University of Borås, Swedish School of Textiles.
    Van Langenhove, L.
    Morphological and material properties of polyethyleneterephthalate (PET) fibres with spores incorporated2014In: Fibres & Textiles in Eastern Europe, ISSN 1230-3666, Vol. 22, no 4, p. 29-36Article in journal (Refereed)
    Abstract [en]

    Owing to the current demand for textiles with new functionalities and improved properties, there has been a continuous effort to modify Polyethylene terephthalate (PET) materials. In our previous study, we demonstrated that Bacillus amyloliquefaciens spores can be incorporated into PET fibres during extrusion. However, the extent to which they can be incorporated without fundamentally changing the properties of the fibres is unknown. In this work, scanning electron microscopy (SEM), transmission electron microscopy (TEM), optical microscopy (OM), differential scanning calorimetry (DSC), a Favimat tensile tester, and Raman and Fourier transform infrared spectroscopy (FT-IR) were used to study the properties of PET/spore fibres. The tensile strength, Young’s modulus and elongation at break were dependent on the spore concentration. Additionally the degree of crystallinity increased slightly, whereas the melting and crystallisation temperatures remained constant at all spore concentration levels. Nevertheless the properties of the fibres fall within the acceptable range of variation and are found to be as good as normal PET fibres.

  • 48.
    Dasa, Kris Triwulan
    et al.
    Universitas Gadjah Mada.
    Westman, Supansa Y.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Millati, Ria
    Universitas Gadjah Mada.
    Cahyanto, Muhammad Nur
    Universitas Gadjah Mada.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Niklasson, Claes
    Chalmers.
    Inhibitory Effect of Long-Chain Fatty Acids on Biogas Production and the Protective Effect of Membrane Bioreactor2016In: BioMed Research International, ISSN 2314-6133, E-ISSN 2314-6141Article in journal (Refereed)
    Abstract [en]

    Anaerobic digestion of lipid-containing wastes for biogas production is often hampered by the inhibitory effect of long-chain fatty acids (LCFAs). In this study, the inhibitory effects of LCFAs (palmitic, stearic, and oleic acid) on biogas production as well as the protective effect of a membrane bioreactor (MBR) against LCFAs were examined in thermophilic batch digesters. The results showed that palmitic and oleic acid with concentrations of 3.0 and 4.5 g/L resulted in >50% inhibition on the biogas production, while stearic acid had an even stronger inhibitory effect. The encased cells in the MBR system were able to perform better in the presence of LCFAs. This system exhibited a significantly lower percentage of inhibition than the free cell system, not reaching over 50% at any LCFA concentration tested.[on SciFinder (R)]

  • 49.
    Dehkhoda, Anahita
    et al.
    University of Borås, School of Engineering.
    Brandberg, Tomas
    University of Borås, School of Engineering.
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Comparison of vacuum and high pressure evaporated wood hydrolyzate for ethanol production by repeated fed-batch using flocculating Saccharomyces cerevisiae2009In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 4, no 1, p. 309-320Article in journal (Refereed)
    Abstract [en]

    Comparison of vacuum and high pressure evaporated wood hydrolyzate for ethanol production by repeated fed-batch using flocculating Saccharomyces cerevisiae

  • 50. Dehnavi, Gholamali Z.
    et al.
    Lauceria, Jose L.
    Rodriguez, Dani
    Beaton, Milagros
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Martin, Carlos
    Fractionation of the main components of barley spent grains from a microbrewery2011In: Cellulose Chemistry and Technology, ISSN 0576-9787, Vol. 45, no 5-6, p. 339-345Article in journal (Refereed)
    Abstract [en]

    The chemical composition of barley spent grains generated in a microbrewery and their fractionation by acid hydrolysis and delignification were investigated. The material contained high amount of carbohydrates (60%), while its lignin content was lower than that reported for other sorts of barley spent grains. Different dilute-acid hydrolysis methods were evaluated for separating the main components of the spent grains, without affecting the sugars generated by starch hydrolysis. The utilization of a two-step dilute-acid hydrolysis approach allowed to hydrolyse starch in a first step, at 100 ºC, and hemicelluloses in a second step, at 121 ºC. Acetosolv and alkaline delignification were used for solubilising the lignin fraction. A higher lignin solubilisation (95% of the lignin contained in the raw material) was achieved after alkaline delignification, whereas only 34% of the initial lignin was removed by direct acetosolv. When the acetosolv treatment was combined with acid hydrolysis, lignin solubilisation increased to 74%. Lignin was precipitated from the liquors at recovery rates from 40 to 93%, as depending on the hydrolysis/delignification method used.

1234567 1 - 50 of 332
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf