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  • 1. 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)
  • 2.
    Brancoli, Pedro
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Ferreira, Jorge A.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Bolton, Kim
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Changes in carbon footprint when integrating production of filamentous fungi in 1st generation ethanol plants2017In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976Article in journal (Refereed)
    Abstract [en]

    Integrating the cultivation of edible filamentous fungi in the thin stillage from ethanol production is presently being considered. This integration can increase the ethanol yield while simultaneously producing a new value-added protein-rich biomass that can be used for animal feed. This study uses life cycle assessment to determine the change in greenhouse gas (GHG) emissions when integrating the cultivation of filamentous fungi in ethanol production. The result shows that the integration performs better than the current scenario when the fungal biomass is used as cattle feed for system expansion and when energy allocation is used. It performs worse if the biomass is used as fish feed. Hence, integrating the cultivation of filamentous fungi in 1st generation ethanol plants combined with proper use of the fungi can lead to a reduction of GHG emissions which, considering the number of existing ethanol plants, can have a significant global impact.

  • 3.
    Chandolias, Konstantinos
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business. Research Centre for Resource Recovery.
    Pardaev, Sindor
    University of Borås, Faculty of Textiles, Engineering and Business. University of Samarkand.
    Taherzadeh, Mohammad
    University of Borås, Faculty of Textiles, Engineering and Business. Research Centre for Resource Recovery.
    Biohydrogen and carboxylic acids production from wheat straw hydrolysate2016In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976Article in journal (Refereed)
  • 4.
    Ferreira, Jorge A.
    et al.
    University of Borås, School of Engineering.
    Lennartsson, Patrik R.
    University of Borås, School of Engineering.
    Edebo, Lars
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Zygomycetes-based biorefinery: Present status and future prospects2013In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 135, p. 523-532Article in journal (Refereed)
    Abstract [en]

    Fungi of the phylum Zygomycetes fulfil all requirements for being utilized as core catalysts in biorefineries, and would be useful in creating new sustainable products. Apart from the extended use of Zygomycetes in preparing fermented foods, industrial metabolites such as lactic acid, fumaric acid, and ethanol are produced from a vast array of feedstocks with the aid of Zygomycetes. These fungi produce enzymes that facilitate their assimilation of various complex substrates, e.g., starch, cellulose, phytic acid, and proteins, which is relevant from an industrial point of view. The enzymes produced are capable of catalyzing various reactions involved in biodiesel production, preparation of corticosteroid drugs, etc. Biomass produced with the aid of Zygomycetes consists of proteins with superior amino acid composition, but also lipids and chitosan. The biomass is presently being tested for animal feed purposes, such as fish feed, as well as for lipid extraction and chitosan production. Complete or partial employment of Zygomycetes in biorefining procedures is consequently attractive, and is expected to be implemented within a near future.

  • 5.
    Ferreira, Jorge A.
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Mahboubi, Amir
    University of Borås, Faculty of Textiles, Engineering and Business.
    Lennartsson, Patrik R.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Waste biorefineries using filamentous ascomycetes fungi: Present status and future prospects2016In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 215, no sept, p. 334-345Article in journal (Refereed)
    Abstract [en]

    Filamentous ascomycetes fungi have had important roles in natural cycles, and are already used industrially for e.g. supplying of citric, gluconic and itaconic acids as well as many enzymes. Faster human activities result in higher consumption of our resources and producing more wastes. Therefore, these fungi can be explored to use their capabilities to convert back wastes to resources. The present paper reviews the capabilities of these fungi in growing on various residuals, producing lignocellulose-degrading enzymes and production of organic acids, ethanol, pigments, etc. Particular attention has been on Aspergillus, Fusarium, Neurospora and Monascus genera. Since various species are used for production of human food, their biomass can be considered for feed applications and so biomass compositional characteristics as well as aspects related to culture in bioreactor are also provided. The review has been further complemented with future research avenues.[on SciFinder (R)]

  • 6.
    Ishola, Mofoluwake M.
    et al.
    University of Borås, School of Engineering.
    Isroi, Isroi
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Effect of fungal and phosphoric acid pretreatment on ethanol production from oil palm empty fruit bunches (OPEFB)2014In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 165, p. 9-12Article in journal (Refereed)
    Abstract [en]

    Oil palm empty fruit bunches (OPEFB), a lignocellulosic residue of palm oil industries was examined for ethanol production. Milled OPEFB exposed to simultaneous saccharification and fermentation (SSF) with enzymes and Saccharomyces cerevisiae resulted just in 14.5% ethanol yield compared to the theoretical yield. Therefore, chemical pretreatment with phosphoric acid, a biological pretreatment with white-rot fungus Pleurotus floridanus, and their combination were carried out on OPEFB prior to the SSF. Pretreatment with phosphoric acid, combination of both methods and just fungal pretreatment improved the digestibility of OPEFB by 24.0, 16.5 and 4.5 times, respectively. During the SSF, phosphoric acid pretreatment, combination of fungal and phosphoric acid pretreatment and just fungal pretreatment resulted in the highest 89.4%, 62.8% and 27.9% of the theoretical ethanol yield, respectively. However, the recovery of the OPEFB after the fungal pretreatment was 98.7%, which was higher than after phosphoric acid pretreatment (36.5%) and combined pretreatment (45.2%).

  • 7.
    Ishola, Mofoluwake M.
    et al.
    University of Borås, School of Engineering.
    Jahandideh, A
    Haidarian, B
    Brandberg, T
    University of Borås, School of Engineering.
    Taherzadeh, M J
    University of Borås, School of Engineering.
    Simultaneous saccharification, filtration and fermentation (SSFF): A novel method for bioethanol production from lignocellulosic biomass2013In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 133, p. 68-73Article in journal (Refereed)
    Abstract [en]

    Simultaneous saccharification, filtration and fermentation (SSFF) was developed for lignocellulosic ethanol production. In SSFF, pretreated lignocellulosic material is enzymatically hydrolyzed in a reactor, while the suspension is continuously pumped through a cross-flow membrane. The retentate goes back to the hydrolysis vessel, while a clear sugar-rich filtrate continuously perfuses through the fermentation vessel before it is pumped back to the hydrolysis vessel. The capacity and life span of the cross-flow filter module was examined for 4 weeks using enzymatically hydrolyzed slurry, initially with 14.4% suspended solids, without clogging or fouling. An ethanol yield of 85.0% of the theoretical yield was obtained in SSFF and a flocculating strain of Saccharomyces cerevisiae was successfully reused for five cultivations of SSFF.

  • 8.
    Jeihanipour, Azam
    et al.
    University of Borås, School of Engineering.
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Ethanol production from cotton-based waste textiles2009In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 100, no 2, p. 1007-1010Article in journal (Refereed)
    Abstract [en]

    Ethanol production from cotton linter and waste of blue jeans textiles was investigated. In the best case, alkali pretreatment followed by enzymatic hydrolysis resulted in almost complete conversion of the cotton and jeans to glucose, which was then fermented by Saccharomyces cerevisiae to ethanol. If no pretreatment applied, hydrolyses of the textiles by cellulase and P-glucosidase for 24 h followed by simultaneous saccharification and fermentation (SSF) in 4 days, resulted in 0.140-0.145 g ethanol/g textiles, which was 25-26% of the corresponding theoretical yield. A pretreatment with concentrated phosphoric acid prior to the hydrolysis improved ethanol production from the textiles up to 66% of the theoretical yield. However, the best results obtained from alkali pretreatment of the materials by NaOH. The alkaline pretreatment of cotton fibers were carried out with 0-20% NaOH at 0 degrees C, 23 degrees C and 100 degrees C, followed by enzymatic hydrolysis up to 4 days. In general, higher concentration of NaOH resulted in a better yield of the hydrolysis, whereas temperature had a reverse effect and better results were obtained at lower temperature. The best conditions for the alkali pretreatment of the cotton were obtained in this study at 12% NaOH and 0 degrees C and 3 h. In this condition, the materials with 3% solid content were enzymatically hydrolyzed at 85.1% of the theoretical yield in 24 h and 99.1% in 4 days. The alkali pretreatment of the waste textiles at these conditions and subsequent SSF resulted in 0.48 g ethanol/g pretreated textiles used. (c) 2008 Elsevier Ltd. All rights reserved.

  • 9.
    Kabir, Maryam M.
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Rajendran, K.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, M.J.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Sárvári Horváth, I.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Experimental and economical evaluation of bioconversion of forest residues to biogas using organosolv pretreatment2015In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 178, p. 201-8Article in journal (Refereed)
    Abstract [en]

    The methane potential of forest residues was compared after applying organic solvent, i.e., acetic acid, ethanol, and methanol pretreatments using batch anaerobic digestion (AD). The pretreatments were performed at 190 °C with 50% (V/V) organic solvent for 60 min. The accumulated methane yields after 40 days of AD from pretreated forest residues were between 0.23 and 0.34 m3 CH4/kg VS, which shows a significant improvement compared to 0.05 m3 CH4/kg VS, from untreated forest residues. These improvements count up to 50% increase in the methane yields from the pretreated substrates based on expected theoretical yield from carbohydrates. Among the organic solvents, pretreatments with acetic acid and ethanol led to highest methane yields, i.e., over 0.30 m3 CH4/kg VS. However, techno-economical evaluation showed, pretreatment with methanol was more viable financially. The capital investments of the plant operating 20,000 tons of forest residues varied between 56 and 60 million USD, which could be recovered in less than 8 years of operation.

  • 10.
    Karimi, Keikhosro
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    A critical review of analytical methods in pretreatment of lignocelluloses: Composition, imaging, and crystallinity.2016In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 200Article in journal (Refereed)
    Abstract [en]

    Lignocelluloses are widely investigated as renewable substrates to produce biofuels, e.g., ethanol, methane, hydrogen, and butanol, as well as chemicals such as citric acid, lactic acid, and xanthan gum. However, lignocelluloses have a recalcitrance structure to resist microbial and enzymatic attacks; therefore, many physical, thermal, chemical, and biological pretreatment methods have been developed to open up their structure. The efficiency of these pretreatments was studied using a variety of analytical methods that address their image, composition, crystallinity, degree of polymerization, enzyme adsorption/desorption, and accessibility. This paper presents a critical review of the first three categories of these methods as well as their constraints in various applications. The advantages, drawbacks, approaches, practical details, and some points that should be considered in the experimental methods to reach reliable and promising conclusions are also discussed.

  • 11. Karimi, Keikhosro
    et al.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    A critical review on analysis in pretreatment of lignocelluloses: Degree of polymerization, adsorption/desorption, and accessibility2016In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 203, p. 348-356Article in journal (Refereed)
    Abstract [en]

    The pretreatment of lignocelluloses results in changes in the different properties of these materials. In a recent review (Karimi and Taherzadeh, 2016), the details of compositional, imaging, and crystallinity analyses of lignocelluloses were reviewed and critically discussed. Changes in the cellulose degree of polymerization, accessibility, and enzyme adsorption/desorption by pretreatments are also among the effective parameters. This paper deals with the measurement techniques, modifications, and relation to bioconversions, as well as the challenges of these three properties. These analyses are very helpful to investigate the pretreatment processes; however, the pretreatments are very complicated and challenging processes. It is not easily possible to study the effects of only one of these parameters and even to find which one is the dominant one. Moreover, it is not possible to accurately predict the changes in the bioconversion yield using these methods.[on SciFinder (R)]

  • 12.
    Lennartsson, Patrik
    et al.
    University of Borås, School of Engineering.
    Erlandsson, Per
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Integration of the first and second generation bioethanol processes and the importance of by-products2014In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 165, p. 3-8Article in journal (Refereed)
    Abstract [en]

    Lignocellulosic ethanol has obstacles in the investment costs and uncertainties in the process. One solution is to integrate it with the running dry mills of ethanol from grains. However, the economy of these mills, which dominate the world market, are dependent on their by-products DDGS (Distiller’s Dried Grains and Solubles), sold as animal feed. The quality of DDGS therefore must not be negatively influenced by the integration. This puts restraints on the choice of pretreatment of lignocelluloses and utilizing the pentose sugars by food-grade microorganisms. The proposed solution is to use food related filamentous Zygomycetes and Ascomycetes fungi, and to produce fungal biomass as a high-grade animal feed from the residues after the distillation (stillage). This also has the potential to improve the first generation process by increasing the amount of the thin stillage directly sent back into the process, and by decreasing the evaporator based problems.

  • 13.
    Lennartsson, Patrik
    et al.
    University of Borås, School of Engineering.
    Niklasson, Claes
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    A pilot study on lignocelluloses to ethanol and fish feed using NMMO pretreatment and cultivation with Zygomycetes in an airlift reactor2011In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 102, no 6, p. 4425-4432Article in journal (Refereed)
    Abstract [en]

    A complete process for the production of bioethanol and fungal biomass from spruce and birch was investigated. The process included milling, pretreatment with N-methylmorpholine-N-oxide (NMMO), washing of the pretreated wood, enzymatic hydrolysis, and cultivation of the zygomycetes fungi Mucor indicus. Investigated factors included wood chip size (0.5-16 mm), pretreatment time (1-5 h), and scale of the process from bench-scale to 2 m high airlift reactor. Best hydrolysis yields were achieved from wood chips below 2 mm after 5 h of pretreatment. Ethanol yields (mg/g wood) of 195 and 128 for spruce, and 175 and 136 for birch were achieved from bench-scale and airlift, respectively. Fungal biomass yields (mg/g wood) of 103 and 70 for spruce, and 86 and 66 for birch from bench scale and airlift respectively were simultaneously achieved. NMMO pretreatment and cultivation with M. indicus appear to be a good alternative for ethanol production from birch and spruce.

  • 14. Lohrasbi, M.
    et al.
    Pourbafrani, M.
    Niklasson, C.
    Taherzadeh, Mohammad
    University of Borås, School of Engineering.
    Process design and economic analysis of a citrus waste biorefinery with biofuels and limonene as products2010In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 101, no 19, p. 7382-7388Article in journal (Refereed)
    Abstract [en]

    Process design and economic analysis of a biorefinery for the treatment of citrus wastes (CW) at different capacities was carried out. The CW is hydrolyzed using dilute sulfuric acid and then further processed to produce limonene, ethanol and biogas. The total cost of ethanol for base case process with 100,000 tons/year CW capacity was calculated as 0.91 USD/L, assuming 10 USD/ton handling and transportation cost of CW to the plant. However, this price is sensitive to the plant capacity. With constant price of methane and limonene, changing the plant capacity from 25,000 to 400,000 tons CW per year results in reducing ethanol costs from 2.55 to 0.46 USD/L in an economically feasible process. In addition, the ethanol production cost is sensitive to the transportation cost of CW. Increasing this cost from 10 to 30 USD/ton for the base case results in increasing the ethanol costs from 0.91 to 1.42 USD/L.

  • 15.
    Mahboubi, Amir
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business. Biotechnology.
    Ylitervo, Paeivi
    Doyen, Wim
    De Wever, Heleen
    Molenberghs, Bart
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Continuous bioethanol fermentation from wheat straw hydrolysate with high suspended solid content using an immersed flat sheet membrane bioreactor.2017In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 241, p. 296-308Article in journal (Refereed)
    Abstract [en]

    Finding a technol. approach that eases the prodn. of lignocellulosic bioethanol has long been considered as a great industrial challenge. In the current study a membrane bioreactor (MBR) set-up using integrated permeate channel (IPC) membrane panels was used to simultaneously ferment pentose and hexose sugars to ethanol in continuous fermn. of high suspended solid wheat straw hydrolyzate. The MBR was optimized to flawlessly operated at high SS concns. of up to 20% without any significant changes in the permeate flux and transmembrane pressure. By the help of the retained high cell concn., the yeast cells were capable of tolerating and detoxifying the inhibitory medium and succeeded to co-consume all glucose and up to 83% of xylose in a continuous fermn. mode leading to up to 83% of the theor. ethanol yield. [on SciFinder(R)]

  • 16.
    Mahmoodi, P.
    et al.
    Department of Chemical Engineering, Isfahan University of Technology.
    Karimi, K.
    Industrial Biotechnology Group, Research Institute of Biotechnology and Bioengineering, Isfahan University of Technology, Isfahan.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Hydrothermal processing as pretreatment for efficient production of ethanol and biogas from municipal solid waste2018In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 261, p. 166-175Article in journal (Refereed)
    Abstract [en]

    Organic fraction of municipal solid waste (OFMSW) is dominated by carbohydrates, including starch-based and lignocellulosic materials. The OFMSW was hydrothermally pretreated at 100–160 °C for 0–60 min, and then assessed for enzymatic ethanol production, followed by biogas production from the stillage. The highest glucose yield of 520 g/Kg of dry OFMSW, corresponding to 131% increase compared to that of the untreated OFMSW, was obtained after the pretreatment and enzymatic hydrolysis. Through ethanolic fermentation by an inhibitory tolerant fungus, Mucor indicus, 191.10 g ethanol/Kg of dry OFMSW was obtained, which was a 140.9% improvement in the ethanol yield compared to that from the untreated one. Methane production from the stillage (waste residues) resulted in 156 L/Kg OFMSW. In other words, a total of 10,774 KJ energy/Kg of dry OFMSW was generated at the best conditions. 

  • 17. Mohseni Kabir, M.
    et al.
    Niklasson, C.
    Taherzadeh, M.J.
    University of Borås, School of Engineering.
    Sárvári Horváth, I.
    University of Borås, School of Engineering.
    Biogas production from lignocelluloses by N-methylmorpholine-N-oxide (NMMO) pretreatment: Effects of recovery and reuse of NMMO2014In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 161, p. 446-450Article in journal (Refereed)
    Abstract [en]

    The effects of N-methylmorpholine-N-oxide (NMMO) pretreatment on barley straw and forest residues were investigated for biogas production. The pretreatments were performed at 90 °C with 85% NMMO for 3–30 h. The best pretreatment conditions resulted in 100% improvement in methane yield during the subsequent digestion compared to that of the untreated lignocelluloses. Methane yields of 0.23 and 0.15 Nm3 CH4/kg VS were obtained from barley straw and forest residues, respectively, corresponding to 88% and 83% of the theoretical yields. In addition, the effects of the pretreatment with recovered and reused NMMO was also studied over the course of five cycles. Pretreatment with recycled NMMO showed the same performance as the fresh NMMO on barley straw. However, pretreatment of forest residues with recycled NMMO resulted in 55% reduction in methane yield.

  • 18.
    Nair, Ramkumar B
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Kalif, Mahdi
    University of Borås, Faculty of Textiles, Engineering and Business.
    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.
    Mild-temperature dilute acid pretreatment for integration of first and second generation ethanol processes2017In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 245, p. 145-151Article in journal (Refereed)
    Abstract [en]

    The use of hot-water (100 °C) from the 1st generation ethanol plants for mild-temperature lignocellulose pretreatment can possibly cut down the operational (energy) cost of 2nd generation ethanol process, in an integrated model. Dilute-sulfuric and -phosphoric acid pretreatment at 100 °C was carried out for wheat bran and whole-stillage fibers. Pretreatment time and acid type influenced the release of sugars from wheat bran, while acid-concentration was found significant for whole-stillage fibers. Pretreatment led up-to 300% improvement in the glucose yield compared to only-enzymatically treated substrates. The pretreated substrates were 191–344% and 115–300% richer in lignin and glucan, respectively. Fermentation using Neurospora intermedia, showed 81% and 91% ethanol yields from wheat bran and stillage-fibers, respectively. Sawdust proved to be a highly recalcitrant substrate for mild-temperature pretreatment with only 22% glucose yield. Both wheat bran and whole-stillage are potential substrates for pretreatment using waste heat from the 1st generation process for 2nd generation ethanol.

  • 19.
    Nair, Ramkumar
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Valorization of sugar-to-ethanol process waste vinasse: A novel biorefinery approach using edible ascomycetes filamentous fungi2016In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 221, p. 469-476Article in journal (Refereed)
    Abstract [en]

    The aim of the present work was to study the integration of edible ascomycetes filamentous fungi into the existing sugar- or molasses-to-ethanol processes, to grow on vinasse or stillage and produce ethanol and protein-rich fungal biomass. Two fungal strains, Neurospora intermedia and Aspergillus oryzae were examined in shake flasks and airlift-bioreactors, resulting in reduction of vinasse COD by 34% and viscosity by 21%. Utilization of glycerol and sugars were observed, yielding 202.4 or 222.8g dry fungal biomass of N. intermedia or A. oryzae respectively, per liter of vinasse. Integration of the current process at an existing ethanol facility producing about 100,000m(3) of ethanol per year could produce around 200,000-250,000tons of dry fungal biomass (40-45% protein) together with about 8800-12,600m(3) extra ethanol (8.8-12.6% of production-rate improvement).[on SciFinder (R)]

  • 20.
    Oechsner, Hans
    et al.
    University of Hohenheim.
    Khanal, Samir Kumar
    University of Hawaiʻi at Mānoa.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Advances in biogas research and application.2015In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 178, no February 2015, p. 177-Article in journal (Refereed)
  • 21.
    Oluoti, Kehinde
    et al.
    University of Borås, School of Engineering.
    Richards, Tobias
    University of Borås, School of Engineering.
    Doddapaneni, Tharaka
    Kanagasabapathi, DhipanKumar
    Evaluation of the Pyrolysis and Gasification Kinetics of Tropical Wood Biomass2014In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 9, no 2, p. 2179-2190Article in journal (Refereed)
    Abstract [en]

    Two tropical biomass species, teak (Tectona grandis) and obobo (Guarea thompsonii), were obtained in the form of sawmill waste from Nigeria and evaluated to determine their potential for gasification. Pyrolysis and gasification kinetics of the samples were investigated using a thermogravimetric analyser (TGA) at temperatures of 900 oC and 1,000 oC. Four iso-conversional methods, one peak temperature method, and two model-fitting methods were employed to determine the kinetic parameters, i.e. the apparent activation energy Ea, and pre-exponential factor A. Values of the gasification kinetic rate constant K were determined using two gas-solid reaction models: the volumetric reaction model (VRM) and the shrinking core model (SCM). The values obtained for all three kinetic parameters showed good agreement with values derived for samples of non-tropical wood.

  • 22.
    Oluoti, Kehinde
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business. Lagos State University.
    Richards, Tobias
    Pettersson, Anita
    Investigating the morphology and reactivity of chars from Triplochiton scleroxylon pyrolysed under varied conditionsInvestigating the morphology and reactivity of chars from Triplochiton scleroxylon pyrolysed under varied conditions2016In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 208, no 0, p. 94-99Article in journal (Refereed)
    Abstract [en]

    A gasifier may be optimised via a good understanding of the char formation, morphology and reactivity. The effects of varying the pyrolysis pressure and heating rate on the morphology of the char were investigated using a thermogravimetric analyser (TGA), scanning electron microscope (SEM) and micrograph spot analyser. The gasified chars were produced at heating rates of 5, 10 and 20 C/min and pressures of 0.1, 0.4 and 0.6 MPa. All the chars have different degrees of apparent gasification reactivity. The random pore model (RPM) provided a better description of the experiment, with low average error values, h, in all of the cases considered. The alkaline and alkaline earth metals (AAEM) in the tropical wood biomass Arere (Triplochiton scleroxylon) consist predominantly of calcium and could altogether be partly responsible for the noticeably high reactivity nature of the tropical Arere chars

  • 23.
    Osadolor, Osagie Alex
    University of Borås, Faculty of Textiles, Engineering and Business.
    Nair, Ramkumar B
    University of Borås, Faculty of Textiles, Engineering and Business.
    Lennartsson, Patrik R.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Effect of media rheology and bioreactor hydrodynamics on filamentous fungi fermentation of lignocellulosic and starch-based substrates under pseudoplastic flow conditions2018In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 263, p. 250-257Article in journal (Refereed)
    Abstract [en]

    The aim of this work was to study how media rheology and bioreactor hydrodynamics would influence fermentation of lignocellulosic and starch-based substrates under pseudoplastic flow conditions. This was investigated using hydrolyzed wheat straw, wheat-based thin stillage and filamentous fungi as inoculum in bubble column, airlift and horizontal hybrid tubular/bubble column (textile bioreactor) bioreactors. The rheological models showed that the consistency index was dependent on biomass growth (R2 0.99) while the flow behavior index depended on biomass growth and suspended solid (R2 0.99). Oxygen transfer rate above 0.356 mmol-O2/L/h was needed for growing fungi with a cube-root growth rate constant of 0.03 g1/3/L1/3/h. At 1.4 VVM aeration the textile bioreactor performed better than others with minimal foaming, yields of 0.22 ± 0.01 g/g and 0.47 ± 0.01 g/g for ethanol and biomass, substrate consumption rate of 0.38 g/L/h. Operating the bioreactors with air-flowrate to cross-sectional area ratio of 8.75 × 10−3 (m3/s/m2) or more led to sustained foaming.

  • 24.
    Pagés Díaz, Jhosané
    et al.
    University of Borås, School of Engineering.
    Pereda Reyes, Ileana
    Lundin, Magnus
    University of Borås, School of Engineering.
    Sárvári Horváth, Ilona
    University of Borås, School of Engineering.
    Co-digestion of different waste mixtures from agro-industrial activities: Kinetic evaluation and synergetic effects2011In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 102, no 23, p. 10834-10840Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Several wastes from agro-industrial activities were mixed in different ratios to evaluate the co-digestion process. Methane yield (YCH4), specific methanogenic activity (SMA) and a kinetic parameter (k0) were determined. A second feeding was also performed to examine the recovery of bacterial activity after exhaustion. Mixture ratios of 1:1:1:1 and 1:3:4:0.5 (w/w) showed the best performance, with YCH4 of 664; 582 NmL CH4/gVSsubstrate, as well as SMA of 0.12; 0.13 gCODNmLCH4/gVSinoculum/d, respectively, during the digestion of the first feed. It was possible to relate synergetic effects with enhancement in YCH4 by up to 43%, compared with values calculated from YCH4 of the individual substrates. All batches started up the biogas production after an exhaustion period, when a second feed was added. However, long lag phases (up to 21 days) were observed due to stressed conditions caused by the substrate limitation prior to the second feed.

  • 25.
    Patinvoh, Regina J.
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Kalantar Mehrjerdi, Adib
    University of Borås, Faculty of Textiles, Engineering and Business.
    Sarvari, Horvath Ilona
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Dry fermentation of manure with straw in continuous plug flow reactor: Reactor development and process stability at different loading rates2017In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 224, p. 197-205Article in journal (Refereed)
    Abstract [en]

    In this work, a plug flow reactor was developed for continuous dry digestion processes and its efficiency was investigated using untreated manure bedded with straw at 22% total solids content. This newly developed reactor worked successfully for 230days at increasing organic loading rates of 2.8, 4.2 and 6gVS/L/d and retention times of 60, 40 and 28days, respectively. Organic loading rates up to 4.2gVS/L/d gave a better process stability, with methane yields up to 0.163LCH4/gVSadded/d which is 56% of the theoretical yield. Further increase of organic loading rate to 6gVS/L/d caused process instability with lower volatile solid removal efficiency and cellulose degradation.[on SciFinder (R)]

  • 26.
    Patinvoh, Regina J.
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Osadolor, Osagie A.
    Chandolias, Konstantinos
    Sarvari, Horvath Ilona
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Innovative pretreatment strategies for biogas production2017In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 224, p. 13-24Article in journal (Refereed)
    Abstract [en]

    Biogas or biomethane is traditionally produced via anaerobic digestion, or recently by thermochemical or a combination of thermochemical and biological processes via syngas (CO and H2) fermentation. However, many of the feedstocks have recalcitrant structure and are difficult to digest (e.g., lignocelluloses or keratins), or they have toxic compounds (such as fruit flavors or high ammonia content), or not digestible at all (e.g., plastics). To overcome these challenges, innovative strategies for enhanced and economically favorable biogas production were proposed in this review. The strategies considered are commonly known physical pretreatment, rapid decompression, autohydrolysis, acid- or alkali pretreatments, solvents (e.g. for lignin or cellulose) pretreatments or leaching, supercritical, oxidative or biological pretreatments, as well as combined gasification and fermentation, integrated biogas production and pretreatment, innovative biogas digester design, co-digestion, and bio-augmentation.[on SciFinder (R)]

  • 27.
    Patinvoh, Regina
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Osadolor, Osagie Alex
    University of Borås, Faculty of Textiles, Engineering and Business.
    Sárvári Horváth, Ilona
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Cost effective dry anaerobic digestion in textile bioreactors: Experimental and economic evaluation2017In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 245, no Pt A, p. 549-555Article in journal (Refereed)
    Abstract [en]

    The aim of this work was to study dry anaerobic digestion (dry-AD) of manure bedded with straw using textile-based bioreactor in repeated batches. The 90-L reactor filled with the feedstocks (22-30% total solid) and inoculum without any further treatment, while the biogas produced were collected and analyzed. The digestate residue was also analyzed to check its suitability as bio-fertilizer. Methane yield after acclimatization increased from 183 to 290NmlCH4/gVS, degradation time decreased from 136 to 92days and the digestate composition point to suitable bio-fertilizer. The results then used to carry out economical evaluation, which shows dry-AD in textile bioreactors is a profitable method of handling the waste with maximum payback period of 5years, net present value from $7,000 to $9,800,000 (small to large bioreactors) with internal rate of return from 56.6 to 19.3%.

  • 28.
    Patinvoh, Regina
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Osalie, Alex
    University of Borås, Faculty of Textiles, Engineering and Business.
    Chandolias, Konstantinos
    University of Borås, Faculty of Textiles, Engineering and Business.
    Sarvari Horvath, Ilona
    Taherzadeh, Mohammad
    University of Borås, Faculty of Textiles, Engineering and Business.
    Innovative Pretreatment Strategies for Biogas Production2016In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. NovArticle in journal (Refereed)
    Abstract [en]

    Biogas or biomethane is traditionally produced via anaerobic digestion, or recently bythermochemical or a combination of thermochemical and biological processes viasyngas (CO and H2) fermentation. However, many of the substrates feedstocks haverecalcitrant structure and difficult to digest (e.g., lignocelluloses or keratins), or theyhave toxic compounds (such as fruit flavors or high ammonia content), or not digestibleat all (e.g., plastics). To overcome these challenges, innovative strategies for enhancedand economically favorable biogas production were proposed in this review. Thestrategies considered are commonly known physical pretreatment, rapid decompression,autohydrolysis, acid- or alkali pretreatments, solvents (e.g. for lignin or cellulose)pretreatments or leaching, supercritical, oxidative or biological pretreatments, as well ascombined gasification and fermentation, integrated biogas production and

  • 29.
    Pietrzak, Witold
    et al.
    Wroclaw University of Environmental and Life Sciences.
    Kawa-Rygielska, Joanna
    Wroclaw University of Environmental and Life Sciences.
    Krol, Barbara
    Wroclaw University of Environmental and Life Sciences.
    Lennartsson, Patrik R.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Ethanol, feed components and fungal biomass production from field bean (Vicia faba var. equina) seeds in an integrated process2016In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 216, p. 69-76Article in journal (Refereed)
    Abstract [en]

    The use of field beans, a non-food leguminous crop, was studied for ethanol, feed components and fungal biomass production. The seeds were hydrolyzed using enzymes or with combination of acid (H3PO4) and alkaline (Ca(OH)2) pretreatment and enzymatic hydrolysis. Fermentation by Saccharomyces cerevisiae, with or without removal of suspended solids, yielded 38.3-42.5gL(-1) ethanol (71.3-79.2% efficiency). The filtration residues contained ca. 247-326gkg(-1) crude protein, 10.6-15.5% acid detergent fiber and 19.9-29.1% neutral detergent fiber. They were enriched in phenolics (by up to 93.4%) and depleted in condensed tannin (by up to 59.3%) in comparison to the raw material. The thin stillages were used for cultivation of edible fungus Neurospora intermedia which produced 8.5-15.9gL(-1) ethanol and 4.8-16.2gL(-1) biomass containing over 62% protein. The mass balances showed that fermentation of unfiltered mashes was more efficient yielding up to 195.9gkg(-1) ethanol and 84.4% of protein recovery.[on SciFinder (R)]

  • 30. Pourbafrani, Mohammad
    et al.
    Forgács, Gergely
    Sárvári Horváth, Ilona
    University of Borås, School of Engineering.
    Niklasson, Claes
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Production of biofuels, limonene and pectin from citrus wastes2010In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 101, no 11, p. 4246-4250Article in journal (Refereed)
    Abstract [en]

    Production of ethanol, biogas, pectin and limonene from citrus wastes (CWs) by an integrated process was investigated. CWs were hydrolyzed by dilute-acid process in a pilot plant reactor equipped with an explosive drainage. Hydrolysis variables including temperature and residence time were optimized by applying a central composite rotatable experimental design (CCRD). The best sugar yield (0.41 g/g of the total dry CWs) was obtained by dilute-acid hydrolysis at 150 degrees C and 6 min residence time. At this condition, high solubilization of pectin present in the CWs was obtained, and 77.6% of total pectin content of CWs could be recovered by solvent recovery. Degree of esterification and ash content of produced pectin were 63.7% and 4.23%, respectively. In addition, the limonene of the CWs was effectively removed through flashing of the hydrolyzates into an expansion tank. The sugars present in the hydrolyzates were converted to ethanol using baker's yeast, while an ethanol yield of 0.43 g/g of the fermentable sugars was obtained. Then, the stillage and the remaining solid materials of the hydrolyzed CWs were anaerobically digested to obtain biogas. In summary, one ton of CWs with 20% dry weight resulted in 39.641 ethanol, 45 m(3) methane, 8.91 limonene, and 38.8 kg pectin. (C) 2010 Elsevier Ltd. All rights reserved.

  • 31.
    Purwadi, Ronny
    et al.
    University of Borås, School of Engineering.
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    The performance of serial bioreactors in rapid continuous production of ethanol from dilute-acid hydrolyzates using immobilized cells2008In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 99, no 7, p. 2226-2233Article in journal (Refereed)
  • 32. Purwandari, F. A.
    et al.
    Sanjaya, A. P.
    Millati, R.
    Cahyanto, M.N.
    Sárvári Horváth, Ilona
    University of Borås, School of Engineering.
    Niklasson, C.
    Taherzadeh, M.J.
    University of Borås, School of Engineering.
    Pretreatment of oil palm empty fruit bunch (OPEFB) by N-methylmorpholine-N-oxide (NMMO) for biogas production: Structural changes and digestion improvement2013In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 128, no 1, p. 461-466Article in journal (Refereed)
    Abstract [en]

    Pretreatment of OPEFB (oil palm empty fruit bunch) by NMMO (N-methylmorpholine-N-oxide) on its subsequent digestions was investigated. The pretreatments were carried out at 90 and 120 °C for 1, 3, and 5 h in three different modes of dissolution (by 85% NMMO solution), ballooning (79% NMMO solution), and swelling (73% NMMO solution). The total solid recovery after the pretreatment was 89–94%. The pretreatment process did not have a major impact on the composition of OPEFB, other than a reduction of ash from 5.4% up to 1.3%. The best improvement in biogas production was achieved by a dissolution mode pretreatment of OPEFB, using conditions of 85% NMMO, 3 h, and 120 °C. It resulted in 0.408 Nm3/kg VS methane yield and 0.032 Nm3 CH4/kg VS/day initial methane production rate, which correspond in improving by 48% and 167% compared to the untreated OPEFB, respectively.

  • 33. Shafiei, M.
    et al.
    Karimi, K.
    Taherzadeh, Mohammad
    University of Borås, School of Engineering.
    Pretreatment of spruce and oak by N-methylmorpholine-N-oxide (NMMO) for efficient conversion of their cellulose to ethanol2010In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 101, no 13, p. 4914-4918Article in journal (Refereed)
    Abstract [en]

    Pretreatment of softwood spruce and hardwood oak with an industrial cellulose solvent, N-methylmorpholine-N-oxide (NMMO), was investigated prior to enzymatic hydrolysis and fermentation to ethanol. The pretreatments were carried out at 90, 110 and 130 °C for 1–3 h with 85% NMMO solution, followed by non-isothermal simultaneous saccharification and fermentation (NSSF). This NSSF included hydrolysis with cellulase and β-glucosidase for 24 h at 45 °C, followed by continuous saccharification and fermentation with Saccharomyces cerevisiae at 37 °C for 3 days. The NSSF of untreated oak and spruce resulted in 18.6% and 6.8% ethanol compared to the maximum theoretical yield. However, the pretreatment of oak and spruce at 130 °C resulted in almost total conversion of cellulose to ethanol and improved ethanol yield up to 85.4% and 89%, respectively. These numbers are comparable with ethanol from pure glucose with the same strain, which yielded between 84% and 90% of the theoretical ethanol yield.

  • 34. Shafiei, Marzieh
    et al.
    Kabir, Maryam M.
    University of Borås, School of Engineering.
    Zilouei, Hamid
    Sárvári Horváth, Ilona
    University of Borås, School of Engineering.
    Karimi, Keikhosro
    Techno-economical study of biogas production improved by steam explosion pretreatment2013In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 148, p. 53-60Article in journal (Refereed)
    Abstract [en]

    Economic feasibility of steam explosion pretreatment for improvement of biogas production from wheat straw and paper tube residuals was investigated. The process was simulated by Aspen plus®, and the economical feasibility of five different plant capacities was studied by Aspen Process Economic Analyzer. Total project investment of a plant using paper tube residuals or wheat straw was 63.9 or 61.8 million Euros, respectively. The manufacturing cost of raw biogas for these two feedstocks was calculated to 0.36 or 0.48 €/m3 of methane, respectively. Applying steam explosion pretreatment resulted in 13% higher total capital investment while significantly improved the economy of the biogas plant and decreased the manufacturing cost of methane by 36%. The sensitivity analysis showed that 5% improvement in the methane yield and 20% decrease in the raw material price resulted in 5.5% and 8% decrease in the manufacturing cost of methane, respectively.

  • 35. Shafiei, Marzieh
    et al.
    Karimi, Keikhosro
    University of Borås, School of Engineering.
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Techno-economical study of ethanol and biogas from spruce wood by NMMO-pretreatment and rapid fermentation and digestion2011In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 102, no 17, p. 7879-7886Article in journal (Refereed)
    Abstract [en]

    Given that N-methylmorpholine-N-oxide (NMMO) is a promising alternative for the pretreatment of lignocelluloses, a novel process for ethanol and biogas production from wood was developed. The solvent, NMMO, is concentrated by multistage evaporation, and the wood is pretreated with the concentrated NMMO. Thereafter, ethanol is produced by the non-isothermal simultaneous saccharification and fermentation (NSSF) method, which is a rapid and efficient process. The wastewater is treated by upflow anaerobic sludge blanket (UASB) digester for rapid production of biogas. The process was simulated by Aspen plus®. Using mechanical vapor recompression for evaporators in the pretreatment and multi-pressure distillation columns, the energy requirements for the process were minimized. The economical feasibility of the developed biorefinery for five different plant capacities was studied by Aspen Icarus Process Evaluator. The base case was designed to utilize 200,000 tons of spruce wood per year and required M€ 58.3 as the total capital investment, while the production cost of ethanol is calculated to be €/l 0.44.

  • 36.
    Taherzadeh, Mohammad J
    et al.
    Dept. of Chem. Reaction Engineering, Chalmers University of Technology.
    Fox, M.
    Dept. of Chem. Reaction Engineering, Chalmers University of Technology.
    Hjorth, H.
    Department of Clinical Bacteriology, Göteborg University.
    Edebo, L.
    Department of Clinical Bacteriology, Göteborg University.
    Production of mycelium biomass and ethanol from paper pulp sulfite liquor by Rhizopus oryzae2003In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 88, no 3, p. 167-177Article in journal (Refereed)
    Abstract [en]

    The cultivation conditions for Rhizopus oryzae grown in synthetic medium and paper pulp spent sulfite liquor (SSL) were investigated to achieve high biomass and ethanol yields using shake flasks and bioreactors. The fungus assimilated the hexoses glucose, mannose and galactose, and the pentoses xylose and arabinose as well as acetic acid which are present in SSL. The assimilation of hexoses was faster than pentoses during cultivation in a synthetic medium. However, all sugars were assimilated concomitantly during growth in SSL supplemented with ammonium, magnesium, calcium, phosphate, sulfate and trace amounts of some other metal ions (SSL-S). The medium composition had an important influence on biomass yield. The highest biomass yields, viz. 0.18 and 0.43 g biomass/g sugar were obtained, when the cells were cultivated in shake flasks with a synthetic medium containing glucose as carbon and energy source and SSL-S, respectively. The corresponding yields in a bioreactor with more efficient aeration were 0.22 and 0.55 g/g. In addition to the biomass, ethanol, lactic acid, and glycerol were important extracellular metabolites of the cultivation with maximum yields of 0.37, 0.30 and 0.09 g/g, respectively. When the source of sugars in the medium was exhausted, the fungus consumed the metabolites produced, such that the liquid medium was depleted of potential oxidizable nutrients. In general, there was a direct competition between lactic acid and ethanol among the metabolites. Poor medium compositions and cultivation conditions resulted in higher yields of lactic acid, whereas the ethanol and biomass yields were higher in rich media. SSL-S supported good growth of mycelium and a high ethanol yield.

  • 37.
    Taherzadeh, Mohammad J
    et al.
    Chalmers University of Technology.
    Niklasson, C.
    Chalmers University of Technology.
    Lidén, G.
    Chalmers University of Technology.
    Conversion of dilute-acid hydrolyzates of spruce and birch to ethanol by fed-batch fermentation1999In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 69, no 1, p. 59-66Article in journal (Refereed)
    Abstract [en]

    Fermentation techniques for conversion of dilute acid hydrolyzates were examined. Batch and fed-batch fermentations of hydrolyzates from spruce and birch woods were made in a lab-scale (3.31) anaerobic bioreactor using the yeast Saccharomyces cerevisiae. The spruce and birch hydrolyzates contained high initial concentrations of furfural (2.2 and 5.7 g/l) and 5-hydroxymethylfurfural (HMF, 7.3 and 2.4 g/l), and were found to be strongly inhibiting to the yeast strain used in this study. Fermentation of the hydrolyzates was not possible using a batch mode of operation. However, using a fed-batch technique with a suitably adjusted feed rate, it was found possible to completely ferment the glucose and mannose sugars in both hydrolyzates. Most of the furfural (90%), and part of the HMF (40-70%), present in the hydrolyzates was converted during the fed-batch operation. It is suggested that the success of the fed-batch operation is related to the conversion of furfural and HMF.Fermentation techniques for conversion of dilute acid hydrolyzates were examined. Batch and fed-batch fermentations of hydrolyzates from spruce and birch woods were made in a lab-scale (3.31) anaerobic bioreactor using the yeast Saccharomyces cerevisiae. The spruce and birch hydrolyzates contained high initial concentrations of furfural (2.2 and 5.7 g/l) and 5-hydroxymethylfurfural (HMF, 7.3 and 2.4 g/l), and were found to be strongly inhibiting to the yeast strain used in this study. Fermentation of the hydrolyzates was not possible using a batch mode of operation. However, using a fed-batch technique with a suitably adjusted feed rate, it was found possible to completely ferment the glucose and mannose sugars in both hydrolyzates. Most of the furfural (90%), and part of the HMF (40-70%), present in the hydrolyzates was converted during the fed-batch operation. It is suggested that the success of the fed-batch operation is related to the conversion of furfural and HMF.

  • 38.
    Taherzadeh, Mohammad J
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Wong, JW
    Nelles, M
    He, P
    Special Issue on Bioconversion of Food Wastes2018In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 248Article in journal (Other academic)
  • 39.
    Teghammar, Anna
    et al.
    University of Borås, School of Engineering.
    Yngvesson, J.
    Lundin, M.
    Taherzadeh, Mohammad
    University of Borås, School of Engineering.
    Sárvári Horváth, Ilona
    University of Borås, School of Engineering.
    Pretreatment of paper tube residuals for improved biogas production2010In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 101, no 4, p. 1206-1212Article in journal (Refereed)
    Abstract [en]

    Paper tube residuals, which are lignocellulosic wastes, have been studied as substrate for biogas (methane) production. Steam explosion and nonexplosive hydrothermal pretreatment, in combination with sodium hydroxide and/or hydrogen peroxide, have been used to improve the biogas production. The treatment conditions of temperature, time and addition of NaOH and H2O2 were statistically evaluated for methane production. Explosive pretreatment was more successful than the nonexplosive method, and gave the best results at 220 °C, 10 min, with addition of both 2% NaOH and 2% H2O2. Digestion of the pretreated materials at these conditions yielded 493 N ml/g VS methane which was 107% more than the untreated materials. In addition, the initial digestion rate was improved by 132% compared to the untreated samples. The addition of NaOH was, besides the explosion effect, the most important factor to improve the biogas production.

  • 40. Trad, Zaineb
    et al.
    Akimbomi, Julius
    Vial, Christophe
    Larroche, Christian
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Fontaine, Jean-Pierre
    Development of a submerged anaerobic membrane bioreactor for concurrent extraction of volatile fatty acids and biohydrogen production.2015In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 196, no November 2015, p. 290-300Article in journal (Refereed)
    Abstract [en]

    The aim of this work was to study an externally-submerged membrane bioreactor for the cyclic extraction of volatile fatty acids (VFAs) during anaerobic fermentation, combining the advantages of submerged and external technologies for enhancing biohydrogen (BioH2) production from agrowaste. Mixing and transmembrane pressure (TMP) across a hollow fiber membrane placed in a recirculation loop coupled to a stirred tank were investigated, so that the loop did not significantly modify the hydrodynamic properties in the tank. The fouling mechanism, due to cake layer formation, was reversible. A cleaning procedure based on gas scouring and backwashing with the substrate was defined. Low TMP, 10(4)Pa, was required to achieve a 3Lh(-1)m(-2) critical flux. During fermentation, BioH2 production was shown to restart after removing VFAs with the permeate, so as to enhance simultaneously BioH2 production and the recovery of VFAs as platform molecules.

  • 41. Wainaina, Steven
    et al.
    Sárvári Horváth, Ilona
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Biochemicals from food waste and recalcitrant biomass via syngas fermentation: A review2017In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976Article in journal (Refereed)
    Abstract [en]

    An effective method for the production of value-added chemicals from food waste and lignocellulosic materials is a hybrid thermal-biological process, which involves gasification of the solid materials to syngas (primarily CO and H2) followed by fermentation. This paper reviews the recent advances in this process. The special focus is on the cultivation methods that involve the use of single strains, defined mixed cultures and undefined mixed cultures for production of carboxylic acids and higher alcohols. A rate limiting step in these processes is the low mass transfer between the gas and the liquid phases. Therefore, novel techniques that can enhance the gas-liquid mass transfer including membrane- and trickle-bed bioreactors were discussed. Such bioreactors have shown promising results in increasing the volumetric mass transfer coefficient (kLa). High gas pressure also influences the mass transfer in certain batch processes, although the presence of impurities in the gas would impede the process.[on SciFinder (R)]

  • 42.
    Wikandari, Rachma
    et al.
    University of Borås, School of Engineering.
    Gudipudi, S.
    Pandiyan, I.
    Millati, R.
    Taherzadeh, M.J.
    University of Borås, School of Engineering.
    Inhibitory Effect of Fruit Flavors on Methane Production During Anaerobic Digestion2013In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 145, no IFIBiop, p. 188-192Article in journal (Refereed)
    Abstract [en]

    In order to improve biogas production from fruit wastes, the inhibitory effects of fruit flavors on anaerobic digestion were investigated. Batch anaerobic digestion was performed for 30 days using synthetic medium and thermophilic sludge. Three groups of flavor compounds i.e. aldehydes (hexanal, nonanal, and E-2-hexenal), terpenes (car-3-ene, α-pinene, and myrcene), and alcohol (octanol) at concentration of 0.005%, 0.05%, and 0.5% were examined. All the flavor compounds showed inhibitory effect on methane production. The highest methane reduction was obtained at addition of 0.5% of flavor compounds. For terpenoids, the presence of 0.5% of car-3-ene, myrcene, and α-pinene reduced 95%, 75%, and 77% of methane production, respectively. For aldehydes, addition of 0.5% concentration resulted in more than 99% methane reduction for hexanal and E-2-hexenal, and 84% methane reduction for nonanal. For alcohol, the presence of 0.5% octanol decreased 99% methane production.

  • 43.
    Wikandari, Rachma
    et al.
    University of Borås, School of Engineering.
    Youngsukkasem, S.
    University of Borås, School of Engineering.
    Millati, R.
    Taherzadeh, M.J.
    University of Borås, School of Engineering.
    Performance of semi-continuous membrane bioreactor in biogas production from toxic feedstock containing D-limonene2014In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 170, p. 350-355Article in journal (Refereed)
    Abstract [en]

    A novel membrane bioreactor configuration containing both free and encased cells in a single reactor was proposed in this work. The reactor consisted of 120 g/L of free cells and 120 g/L of encased cells in a polyvinylidene fluoride membrane. Microcrystalline cellulose (Avicel) and d-Limonene were used as the models of substrate and inhibitor for biogas production, respectively. Different concentrations of d-Limonene i.e., 1, 5, and 10 g/L were tested, and an experiment without the addition of d-Limonene was prepared as control. The digestion was performed in a semi-continuous thermophilic reactor for 75 days. The result showed that daily methane production in the reactor with the addition of 1 g/L d-Limonene was similar to that of control. A lag phase was observed in the presence of 5 g/L d-Limonene; however, after 10 days, the methane production increased and reached a similar production to that of the control after 15 days.

  • 44. Yazdani, Parviz
    et al.
    Zamani, Akram
    University of Borås, Faculty of Textiles, Engineering and Business.
    Karimi, Keikhosro
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Characterization of Nizimuddinia zanardini macroalgae biomass composition and its potential for biofuel production.2015In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 176, p. 196-202Article in journal (Refereed)
    Abstract [en]

    Nizimuddinia zanardini macroalgae, harvested from Persian Gulf, was chem. characterized and employed for the prodn. of ethanol, seaweed ext., alginic acid, and biogas. In order to improve the products yields, the biomass was pretreated with dil. sulfuric acid and hot water. The pretreated and untreated biomasses were subjected to enzymic hydrolysis by cellulase (15 FPU/g) and β-glucosidase (30 IU/g). Hydrolysis yield of glucan was 29.8, 82.5, and 72.7 g/kg for the untreated, hot-water pretreated, and acid pretreated biomass, resp. Anaerobic fermn. of hydrolyzates by Saccharomycescerevisiae resulted in the max. ethanol yield of 34.6 g/kg of the dried biomass. A seaweed ext. contg. mannitol and a solid residue contg. alginic acid were recovered as the main byproducts of the ethanol prodn. On the other hand, the biogas yield from the biomass was increased from 170 to 200 m3 per ton of dried algae biomass by hot water pretreatment. [on SciFinder(R)]

  • 45.
    Ylitervo, Päivi
    et al.
    University of Borås, School of Engineering.
    Doyen, Win
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Fermentation of lignocellulosic hydrolyzate using a submerged membrane bioreactor at high dilution rates2014In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976Article in journal (Refereed)
    Abstract [en]

    A submerged membrane bioreactor (sMBR) was developed to ferment toxic lignocellulosic hydrolyzate to ethanol. The sMBR achieved high cell density of Saccharomyces cerevisiae during continuous cultivation of the hydrolyzate by completely retaining all yeast cells inside the sMBR. The performance of the sMBR was evaluated based on the ethanol yield and productivity at the dilution rates 0.2, 0.4, 0.6, and 0.8 h-1 with the increase of dilution rate. Results show that the yeast in the sMBR was able to ferment the wood hydrolyzate even at high dilution rates, attaining a maximum volumetric ethanol productivity of 7.94 ± 0.10 g L-1 h-1 at a dilution rate of 0.8 h-1. Ethanol yields were stable at 0.44 ± 0.02 g g-1 during all the tested dilution rates, and the ethanol productivity increased from 2.16 ± 0.15 to 7.94 ± 0.10 g L-1 h-1. The developed sMBR systems running at high yeast density demonstrates a potential for a rapid and productive ethanol production from wood hydrolyzate.

  • 46.
    Youngsukkasem, Supansa
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Chandolias, Konstantinos
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås.
    Rapid bio-methanation of syngas in a reverse membrane bioreactor: membrane encased microorganisms2015In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 178, p. 334-40Article in journal (Refereed)
    Abstract [en]

    The performance of a novel reverse membrane bioreactor (RMBR) with encased microorganisms for syngas bio-methanation as well as a co-digestion process of syngas and organic substances was examined. The sachets were placed in the reactors and examined in repeated batch mode. Different temperatures and short retention time were studied. The digesting sludge encased in the PVDF membranes was able to convert syngas into methane at a retention time of 1 day and displayed a similar performance as the free cells in batch fermentation. The co-digestion of syngas and organic substances by the RMBR (the encased cells) showed a good performance without any observed negative effects. At thermophilic conditions, there was a higher conversion of pure syngas and co-digestion using the encased cells compared to at mesophilic conditions.[on SciFinder (R)]

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