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Balasundaram G, Banu R, Varjani S, Kazmi AA, Tyagi VK. Recalcitrant compounds formation, their toxicity, and mitigation: Key issues in biomass pretreatment and anaerobic digestion. CHEMOSPHERE 2022; 291:132930. [PMID: 34800498 DOI: 10.1016/j.chemosphere.2021.132930] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 11/04/2021] [Accepted: 11/14/2021] [Indexed: 06/13/2023]
Abstract
Increasing energy demands and environmental issues have stressed the importance of sustainable methods of energy production. Anaerobic digestion (AD) of the biodegradable waste, i.e., agricultural residues, organic fraction of municipal solid waste (OFMSW), sewage sludge, etc., results in the production of biogas, which is a sustainable and cost feasible technique that reduces the dependence on fossil fuels and also overcomes the problems associated with biomass waste management. To solubilize the organic matter and enhance the susceptibility of hardly biodegradable fraction (i.e., lignocellulosic) for hydrolysis and increase methane production, several pretreatments, including physical, chemical, biological, and hybrid methods have been studied. However, these pretreatment methods under specific operating conditions result in the formation of recalcitrant compounds, such as sugars (xylose, Xylo-oligomers), organic acids (acetic, formic, levulinic acids), and lignin derivatives (poly and mono-phenolic compounds), causing significant inhibitory effects on anaerobic digestion. During the scaling up of these techniques from laboratory to industrial level, the focus on managing inhibitory compounds formed during pretreatment is envisaged to increase because of the need to use recalcitrant feedstocks in anaerobic digestion to increase biogas productivity. Therefore, it is crucial to understand the production mechanism of inhibitory compounds during pretreatment and work out the possible detoxification methods to improve anaerobic digestion. This paper critically reviews the earlier works based on the formation of recalcitrant compounds during feedstocks pretreatment under variable conditions, and their detrimental effects on process performance. The technologies to mitigate recalcitrant toxicity are also comprehensively discussed.
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Affiliation(s)
- Gowtham Balasundaram
- Environmental BioTechnology Group (EBiTG), Department of Civil Engineering, Indian Institute of Technology, Roorkee, Roorkee, 247667, India
| | - Rajesh Banu
- Department of Life Sciences, Central University of Tamil Nadu, Thiruvarur 610005, Tamil Nadu, India
| | - Sunita Varjani
- Gujarat Pollution Control Board, Gandhinagar, 382 010, Gujarat, India
| | - A A Kazmi
- Environmental BioTechnology Group (EBiTG), Department of Civil Engineering, Indian Institute of Technology, Roorkee, Roorkee, 247667, India
| | - Vinay Kumar Tyagi
- Environmental BioTechnology Group (EBiTG), Department of Civil Engineering, Indian Institute of Technology, Roorkee, Roorkee, 247667, India.
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Tinôco D, da Silveira WB. Kinetic model of ethanol inhibition for Kluyveromyces marxianus CCT 7735 (UFV-3) based on the modified Monod model by Ghose & Tyagi. Biologia (Bratisl) 2021. [DOI: 10.1007/s11756-021-00876-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Imamoglu E, Sukan FV. Scale-up and kinetic modeling for bioethanol production. BIORESOURCE TECHNOLOGY 2013; 144:311-320. [PMID: 23886851 DOI: 10.1016/j.biortech.2013.06.118] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Revised: 06/27/2013] [Accepted: 06/29/2013] [Indexed: 06/02/2023]
Abstract
Bioethanol was produced from acidic hydrolysate of rice hulls using recombinant Escherichia coli KO11. Two different issues (scale-up and kinetic modeling) were evaluated simultaneously and concomitantly for bioethanol production. During the step-wise scale-up process from 100 mL shaken flask to 10 L stirred-tank bioreactor, the constant Reynolds number and the constant impeller tip speed were evaluated as scale-up methodologies under laboratory conditions. It was determined that the volumetric bioethanol productivity was 88% higher in 10 L bioreactor in comparison to the value of 0.21 g L(-1) h(-1) in shaken flask. The modified Monod and Luedeking-Piret models provided an accurate approach for the modeling of the experimental data. Ethanol concentration reached the maximum level of 29.03 g/L, which was 5% higher than the value of model prediction in 10 L bioreactor. The findings of this research could contribute to the industrial scale productions especially from lignocellulosic raw materials.
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Affiliation(s)
- Esra Imamoglu
- Department of Bioengineering, Faculty of Engineering, University of Ege, 35100 Bornova, Izmir, Turkey.
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Li X, Yi JP, Ren YL, Yin WP. Modeling alcoholic fermentation of glucose/xylose mixtures by ethanologenic Escherichia coli as a function of pH. ANN MICROBIOL 2013. [DOI: 10.1007/s13213-013-0676-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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Wu W, Fan Z. A general inhibition kinetics model for ethanol production using a novel carbon source: sodium gluconate. Bioprocess Biosyst Eng 2013; 36:1631-40. [DOI: 10.1007/s00449-013-0938-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Accepted: 02/25/2013] [Indexed: 11/24/2022]
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Kwon YJ, Wang F, Li Q, Liu CZ. Effect of temperature on ethanol tolerance of thermotolerantIsshatchenkia orientalisIPE100. Eng Life Sci 2012. [DOI: 10.1002/elsc.201100205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Affiliation(s)
| | - Feng Wang
- National Key Laboratory of Biochemical Engineering; Institute of Process Engineering; Chinese Academy of Sciences; Beijing; P. R. China
| | | | - Chun-Zhao Liu
- National Key Laboratory of Biochemical Engineering; Institute of Process Engineering; Chinese Academy of Sciences; Beijing; P. R. China
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Balan V, Kumar S, Bals B, Chundawat S, Jin M, Dale B. Biochemical and Thermochemical Conversion of Switchgrass to Biofuels. GREEN ENERGY AND TECHNOLOGY 2012. [DOI: 10.1007/978-1-4471-2903-5_7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Xie R, Tu M, Wu Y, Taylor S. Reducing sugars facilitated carbonyl condensation in detoxification of carbonyl aldehyde model compounds for bioethanol fermentation. RSC Adv 2012. [DOI: 10.1039/c2ra21163g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Hawkins GM, Doran-Peterson J. A strain of Saccharomyces cerevisiae evolved for fermentation of lignocellulosic biomass displays improved growth and fermentative ability in high solids concentrations and in the presence of inhibitory compounds. BIOTECHNOLOGY FOR BIOFUELS 2011; 4:49. [PMID: 22074982 PMCID: PMC3256112 DOI: 10.1186/1754-6834-4-49] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Accepted: 11/10/2011] [Indexed: 05/04/2023]
Abstract
BACKGROUND Softwoods are the dominant source of lignocellulosic biomass in the northern hemisphere, and have been investigated worldwide as a renewable substrate for cellulosic ethanol production. One challenge to using softwoods, which is particularly acute with pine, is that the pretreatment process produces inhibitory compounds detrimental to the growth and metabolic activity of fermenting organisms. To overcome the challenge of bioconversion in the presence of inhibitory compounds, especially at high solids loading, a strain of Saccharomyces cerevisiae was subjected to evolutionary engineering and adaptation for fermentation of pretreated pine wood (Pinus taeda). RESULTS An industrial strain of Saccharomyces, XR122N, was evolved using pretreated pine; the resulting daughter strain, AJP50, produced ethanol much more rapidly than its parent in fermentations of pretreated pine. Adaptation, by preculturing of the industrial yeast XR122N and the evolved strains in 7% dry weight per volume (w/v) pretreated pine solids prior to inoculation into higher solids concentrations, improved fermentation performance of all strains compared with direct inoculation into high solids. Growth comparisons between XR122N and AJP50 in model hydrolysate media containing inhibitory compounds found in pretreated biomass showed that AJP50 exited lag phase faster under all conditions tested. This was due, in part, to the ability of AJP50 to rapidly convert furfural and hydroxymethylfurfural to their less toxic alcohol derivatives, and to recover from reactive oxygen species damage more quickly than XR122N. Under industrially relevant conditions of 17.5% w/v pretreated pine solids loading, additional evolutionary engineering was required to decrease the pronounced lag phase. Using a combination of adaptation by inoculation first into a solids loading of 7% w/v for 24 hours, followed by a 10% v/v inoculum (approximately equivalent to 1 g/L dry cell weight) into 17.5% w/v solids, the final strain (AJP50) produced ethanol at more than 80% of the maximum theoretical yield after 72 hours of fermentation, and reached more than 90% of the maximum theoretical yield after 120 hours of fermentation. CONCLUSIONS Our results show that fermentation of pretreated pine containing liquid and solids, including any inhibitory compounds generated during pretreatment, is possible at higher solids loadings than those previously reported in the literature. Using our evolved strain, efficient fermentation with reduced inoculum sizes and shortened process times was possible, thereby improving the overall economic viability of a woody biomass-to-ethanol conversion process.
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Affiliation(s)
- Gary M Hawkins
- Microbiology Department, University of Georgia, Athens, GA 30602, USA
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Weedy lignocellulosic feedstock and microbial metabolic engineering: advancing the generation of ‘Biofuel’. Appl Microbiol Biotechnol 2010; 89:1289-303. [DOI: 10.1007/s00253-010-3057-6] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 12/01/2010] [Accepted: 12/01/2010] [Indexed: 10/18/2022]
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Chen Y. Development and application of co-culture for ethanol production by co-fermentation of glucose and xylose: a systematic review. J Ind Microbiol Biotechnol 2010; 38:581-97. [PMID: 21104106 DOI: 10.1007/s10295-010-0894-3] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Accepted: 10/21/2010] [Indexed: 01/29/2023]
Abstract
This article reviews current co-culture systems for fermenting mixtures of glucose and xylose to ethanol. Thirty-five co-culture systems that ferment either synthetic glucose and xylose mixture or various biomass hydrolysates are examined. Strain combinations, fermentation modes and conditions, and fermentation performance for these co-culture systems are compared and discussed. It is noted that the combination of Pichia stipitis with Saccharomyces cerevisiae or its respiratory-deficient mutant is most commonly used. One of the best results for fermentation of glucose and xylose mixture is achieved by using co-culture of immobilized Zymomonas mobilis and free cells of P. stipitis, giving volumetric ethanol production of 1.277 g/l/h and ethanol yield of 0.49-0.50 g/g. The review discloses that, as a strategy for efficient conversion of glucose and xylose, co-culture fermentation for ethanol production from lignocellulosic biomass can increase ethanol yield and production rate, shorten fermentation time, and reduce process costs, and it is a promising technology although immature.
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Affiliation(s)
- Yanli Chen
- Department of Chemical Engineering, Auburn University, Auburn, AL 36849, USA.
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Chen ML, Wang FS. Optimization of a Fed-Batch Simultaneous Saccharification and Cofermentation Process from Lignocellulose to Ethanol. Ind Eng Chem Res 2010. [DOI: 10.1021/ie1001982] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ming-Liang Chen
- Department of Chemical Engineering, National Chung Cheng University, Chia-yi 62102, Taiwan
| | - Feng-Sheng Wang
- Department of Chemical Engineering, National Chung Cheng University, Chia-yi 62102, Taiwan
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Peterson JD, Ingram LO. Anaerobic respiration in engineered Escherichia coli with an internal electron acceptor to produce fuel ethanol. Ann N Y Acad Sci 2008; 1125:363-72. [PMID: 18378606 DOI: 10.1196/annals.1419.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Environmental concerns and unease with U.S. dependence on foreign oil have renewed interest in converting biomass into fuel ethanol. The volume of plant matter available makes lignocellulose conversion to ethanol desirable, although no one isolated organism has been shown to break bonds in lignocellulose and efficiently metabolize resulting sugars into one product. This work reviews directed engineering coupled with metabolic evolution resulting in microbial biocatalysts that produce up to 45 g L(-1) ethanol in 48 hours in a simple mineral salts medium and that convert various compounds of lignocellulosic materials to ethanol. Mutations contributing to ethanologenesis are discussed along with adding enzymatic capabilities to existing biocatalysts in order to decrease the commercial enzymes required to reduce plant matter into fermentable sugars.
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Georgieva TI, Skiadas IV, Ahring BK. Effect of temperature on ethanol tolerance of a thermophilic anaerobic ethanol producerThermoanaerobacter A10: Modeling and simulation. Biotechnol Bioeng 2007; 98:1161-70. [PMID: 17575556 DOI: 10.1002/bit.21536] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The low ethanol tolerance of thermophilic anaerobic bacteria (<2%, v/v) is a major obstacle for their industrial exploitation for ethanol production. The ethanol tolerance of the thermophilic anaerobic ethanol-producing strain Thermoanaerobacter A10 was studied during batch tests of xylose fermentation at a temperature range of 50-70 degrees C with exogenously added ethanol up to approximately 6.4% (v/v). At the optimum growth temperature of 70 degrees C, the strain was able to tolerate 4.7% (v/v) ethanol, and growth was completely inhibited at 5.6% (v/v). A higher ethanol tolerance was found at lower temperatures. At 60 degrees C, the strain was able to tolerate at least 5.1% (v/v) ethanol. A generalized form of Monod kinetic equation proposed by Levenspiel was used to describe the ethanol (product) inhibition. The model predicted quite well the experimental data for the temperature interval 50-70 degrees C, and the maximum specific growth rate and the toxic power (n), which describes the order of ethanol inhibition at each temperature, were estimated. The toxic power (n) was 1.33 at 70 degrees C, and corresponding critical inhibitory product concentration (P(crit)) above which no microbial growth occurs was determined to be 5.4% (v/v). An analysis of toxic power (n) and P(crit) showed that the optimum temperature for combined microbial growth and ethanol tolerance was 60 degrees C. At this temperature, the toxic power (n), and P(crit) were 0.50, and 6.5% (v/v) ethanol, respectively. From a practical point of view, the model may be applied to compare the ethanol inhibition (ethanol tolerance) on microbial growth of different thermophilic anaerobic bacterial strains.
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Affiliation(s)
- Tania I Georgieva
- BioScience and Technology Group, BioCentrum-DTU, Technical University of Denmark, Building 227, DK-2800 Lyngby, Denmark
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Cardona CA, Sánchez OJ. Fuel ethanol production: process design trends and integration opportunities. BIORESOURCE TECHNOLOGY 2007; 98:2415-57. [PMID: 17336061 DOI: 10.1016/j.biortech.2007.01.002] [Citation(s) in RCA: 319] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2006] [Revised: 01/04/2007] [Accepted: 01/04/2007] [Indexed: 05/11/2023]
Abstract
Current fuel ethanol research and development deals with process engineering trends for improving biotechnological production of ethanol. In this work, the key role that process design plays during the development of cost-effective technologies is recognized through the analysis of major trends in process synthesis, modeling, simulation and optimization related to ethanol production. Main directions in techno-economical evaluation of fuel ethanol processes are described as well as some prospecting configurations. The most promising alternatives for compensating ethanol production costs by the generation of valuable co-products are analyzed. Opportunities for integration of fuel ethanol production processes and their implications are underlined. Main ways of process intensification through reaction-reaction, reaction-separation and separation-separation processes are analyzed in the case of bioethanol production. Some examples of energy integration during ethanol production are also highlighted. Finally, some concluding considerations on current and future research tendencies in fuel ethanol production regarding process design and integration are presented.
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Affiliation(s)
- Carlos A Cardona
- Department of Chemical Engineering, National University of Colombia at Manizales, Cra. 27 No. 64-60 Of. F-505, Manizales, Caldas, Colombia.
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Okuda N, Ninomiya K, Takao M, Katakura Y, Shioya S. Microaeration enhances productivity of bioethanol from hydrolysate of waste house wood using ethanologenic Escherichia coli KO11. J Biosci Bioeng 2007; 103:350-7. [PMID: 17502277 DOI: 10.1263/jbb.103.350] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2006] [Accepted: 01/17/2007] [Indexed: 11/17/2022]
Abstract
This is the first study showing the successful application of waste house wood (WHW) to the pilot-scale production of bioethanol by hydrolysis using diluted acid and fermentation using the ethanologenic recombinant Escherichia coli KO11. The major sugars in the WHW hydrolysate were glucose, mannose and xylose; the percentages were approximately 35%, 35% and 20% (w/w), respectively. In anaerobic fermentation using a 5-l reactor in which the oxygen transfer rate (OTR) was 0 mmol/(l x h), KO11 consumed only 25% of the xylose in the WHW hydrolysate over the examined fermentation time of 100 h; however, hexoses such as glucose and mannose were consumed completely. Microaeration at an OTR of 4 mmol/(l x h) enhanced the xylose utilization ratio of KO11 to 100%, at which the ethanol concentration was 35.4 g/l and the ethanol yield was 0.42, although the maximum ethanol concentrations were 28.8 and 26.6 g/l at OTRs of 0 mmol/(l x h) and 15 mmol/(l x h), respectively. Moreover, this microaerobic fermentation at OTR of 4 mmol/(l x h) was applied to 1000-l scale bioethanol production using the WHW hydrolysate. The xylose utilization ratio reached 100% and the ethanol yield was determined to be 0.45 for a 63-h fermentation, which were comparable to those obtained from the laboratory-scale fermentation.
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Affiliation(s)
- Naoyuki Okuda
- Bio Business Development Group, Tsukishima Kikai Co., Ltd., 17-15 Tsukuda 2-Chome, Chuo-ku, Tokyo 104-0051, Japan
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Jarboe LR, Grabar TB, Yomano LP, Shanmugan KT, Ingram LO. Development of ethanologenic bacteria. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2007; 108:237-61. [PMID: 17665158 DOI: 10.1007/10_2007_068] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The utilization of lignocellulosic biomass as a petroleum alternative faces many challenges. This work reviews recent progress in the engineering of Escherichia coli and Klebsiella oxytoca to produce ethanol from biomass with minimal nutritional supplementation. A combination of directed engineering and metabolic evolution has resulted in microbial biocatalysts that produce up to 45 g L(-1) ethanol in 48 h in a simple mineral salts medium, and convert various lignocellulosic materials to ethanol. Mutations contributing to ethanologenesis are discussed. The ethanologenic biocatalyst design approach was applied to other commodity chemicals, including optically pure D: (-)- and L: (+)-lactic acid, succinate and L: -alanine with similar success. This review also describes recent progress in growth medium development, the reduction of hemicellulose hydrolysate toxicity and reduction of the demand for fungal cellulases.
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Affiliation(s)
- L R Jarboe
- Department of Microbiology and Cell Science, University of Florida, 32611, Gainesville, FL 32611, USA.
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Conditioning hemicellulose hydrolysates for fermentation: Effects of overliming pH on sugar and ethanol yields. Process Biochem 2006. [DOI: 10.1016/j.procbio.2006.03.028] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Helle SS, Murray A, Lam J, Cameron DR, Duff SJB. Xylose fermentation by genetically modified Saccharomyces cerevisiae 259ST in spent sulfite liquor. BIORESOURCE TECHNOLOGY 2004; 92:163-171. [PMID: 14693449 DOI: 10.1016/j.biortech.2003.08.011] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Spent sulfite pulping liquor (SSL) is a high-organic content byproduct of acid bisulfite pulp manufacture which is fermented to make industrial ethanol. SSL is typically concentrated to 240 g/l (22% w/w) total solids prior to fermentation, and contains up to 24 g/l xylose and 30 g/l hexose sugars, depending upon the wood species used. The xylose present in SSL is difficult to ferment using natural xylose-fermenting yeast strains due to the presence of inhibitory compounds, such as organic acids. Using sequential batch shake flask experiments, Saccharomyces cerevisiae 259ST, which had been genetically modified to ferment xylose, was compared with the parent strain, 259A, and an SSL adapted strain, T2, for ethanol production during SSL fermentation. With an initial SSL pH of 6, without nutrient addition or SSL pretreatment, the ethanol yield ranged from 0.32 to 0.42 g ethanol/g total sugar for 259ST, compared to 0.15-0.32 g ethanol/g total sugar for non-xylose fermenting strains. For most fermentations, minimal amounts of xylitol (<1 g/l) were produced, and glycerol yields were approximately 0.12 g glycerol/g sugar consumed. By using 259ST for SSL fermentation up to 130% more ethanol can be produced compared to fermentations using non-xylose fermenting yeast.
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Affiliation(s)
- Steve S Helle
- UBC Department of Chemical and Biological Engineering, 2216 Main Mall, Vancouver, BC, Canada V6T 1Z4
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Helle S, Cameron D, Lam J, White B, Duff S. Effect of inhibitory compounds found in biomass hydrolysates on growth and xylose fermentation by a genetically engineered strain of S. cerevisiae. Enzyme Microb Technol 2003. [DOI: 10.1016/s0141-0229(03)00214-x] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Ward OP, Singh A. Bioethanol technology: developments and perspectives. ADVANCES IN APPLIED MICROBIOLOGY 2003; 51:53-80. [PMID: 12236060 DOI: 10.1016/s0065-2164(02)51001-7] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Owen P Ward
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
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The effect of overliming on the toxicity of dilute acid pretreated lignocellulosics: the role of inorganics, uronic acids and ether-soluble organics. Enzyme Microb Technol 2000; 27:240-247. [PMID: 10899549 DOI: 10.1016/s0141-0229(00)00216-7] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Although the treatment of dilute acid pretreated lignocellulosics with calcium hydroxide or carbonate (overliming) is known to improve the fermentability of carbohydrate-rich hydrolyzate streams, a firm understanding of the chemistry behind the process is lacking. Quantitative evaluation of inorganics, uronic acids, and non-polar organics indicates that only a portion of the improvement can be ascribed to these materials. Upon overliming the concentrations of inorganics either increase (Ca, Mg), decrease (Fe, P, Zn, K) or remain relatively the same (Al, Na). Furthermore, organic compounds that are not extractable with tert-butyl methyl ether (MTBE) are toxic to Zymomonas mobilis CP4(pZB5). Overliming and direct neutralization are somewhat effective in removing sulfate anions, although sulfate toxicity is considerably less than that of acetic acid. Uronic acids were found to be non-toxic under pH controlled conditions.
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Stenberg K, Galbe M, Zacchi G. The influence of lactic acid formation on the simultaneous saccharification and fermentation (SSF) of softwood to ethanol. Enzyme Microb Technol 2000. [DOI: 10.1016/s0141-0229(99)00127-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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A. Amartey S, C. J. Leung P, Baghaei-Yazdi N, J. Leak D, S. Hartley B. Fermentation of a wheat straw acid hydrolysate by Bacillus stearothermophilus T-13 in continuous culture with partial cell recycle. Process Biochem 1999. [DOI: 10.1016/s0032-9592(98)00093-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Abstract
This paper shows that differences in growth behavior of Escherichia coli strain HB101 and strain HB101[pGEc47] can be related to yeast extract-enriched medium rather than plasmid properties. An optimal medium for growth of E. coli HB101[pGEc47] was designed based on the individual yield coefficients for specific medium components (NH4+ 6 g g-1, PO43- 14 g g-1, SO42- 50 g g-1). The yield coefficient for L-leucine depends on the glucose content of the medium (20 g g-1 for 3% glucose, 40 g g-1 for 1% glucose) and the yield coefficient for L-proline depends on the cultivation mode (20 g g-1 for batch cultivation, 44 g g-1 for continuous cultivation). Growth on defined medium after medium optimization is as rapid as on complex medium (0. 42-0.45 h-1). The critical dilution rate (DR) in the defined medium above which undesired production of acetic acid occurs is in the range of 0.23-0.26 h-1.
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Affiliation(s)
- S A Rothen
- Institute of Biotechnology, Swiss Federal Institute of Technology, ETH-Hoenggerberg/HPT, CH-8093 Zürich
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Saucedo VM, Karim MN. Experimental optimization of a real time fed-batch fermentation process using Markov decision process. Biotechnol Bioeng 1997; 55:317-27. [DOI: 10.1002/(sici)1097-0290(19970720)55:2<317::aid-bit9>3.0.co;2-l] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Olsson L, Hahn-Hägerdal B. Fermentation of lignocellulosic hydrolysates for ethanol production. Enzyme Microb Technol 1996. [DOI: 10.1016/0141-0229(95)00157-3] [Citation(s) in RCA: 498] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Saucedo VM, Karim M. On-line optimization of stochastic processes using Markov Decision Processes. Comput Chem Eng 1996. [DOI: 10.1016/0098-1354(96)00126-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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