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Bioreactor and process design for 2G ethanol production from xylose using industrial S. cerevisiae and commercial xylose isomerase. Biochem Eng J 2023. [DOI: 10.1016/j.bej.2022.108777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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2
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Abstract
Glucose isomerase (GI, also known as xylose isomerase) reversibly isomerizes D-glucose and D-xylose to D-fructose and D-xylulose, respectively. GI plays an important role in sugar metabolism, fulfilling nutritional requirements in bacteria. In addition, GI is an important industrial enzyme for the production of high-fructose corn syrup and bioethanol. This review introduces the functions, structure, and applications of GI, in addition to presenting updated information on the characteristics of newly discovered GIs and structural information regarding the metal-binding active site of GI and its interaction with the inhibitor xylitol. This review provides an overview of recent advancements in the characterization and engineering of GI, as well as its industrial applications, and will help to guide future research in this field.
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Miyamoto RY, de Melo RR, de Mesquita Sampaio IL, de Sousa AS, Morais ER, Sargo CR, Zanphorlin LM. Paradigm shift in xylose isomerase usage: a novel scenario with distinct applications. Crit Rev Biotechnol 2021; 42:693-712. [PMID: 34641740 DOI: 10.1080/07388551.2021.1962241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Isomerases are enzymes that induce physical changes in a molecule without affecting the original molecular formula. Among this class of enzymes, xylose isomerases (XIs) are the most studied to date, partly due to their extensive application in industrial processes to produce high-fructose corn sirups. In recent years, the need for sustainable initiatives has triggered efforts to improve the biobased economy through the use of renewable raw materials. In this context, D-xylose usage is crucial as it is the second-most abundant sugar in nature. The application of XIs in biotransforming xylose, enabling downstream metabolism in several microorganisms, is a smart strategy for ensuring a low-carbon footprint and producing several value-added biochemicals with broad industrial applications such as in the food, cosmetics, pharmaceutical, and polymer industries. Considering recent advancements that have expanded the range of applications of XIs, this review provides a comprehensive and concise overview of XIs, from their primary sources to the biochemical and structural features that influence their mechanisms of action. This comprehensive review may help address the challenges involved in XI applications in different industries and facilitate the exploitation of xylose bioprocesses.
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Affiliation(s)
- Renan Yuji Miyamoto
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil.,Faculty of Pharmaceutical Sciences (FCF), State University of Campinas (UNICAMP), Campinas, Brazil
| | - Ricardo Rodrigues de Melo
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
| | - Isabelle Lobo de Mesquita Sampaio
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil.,Faculty of Food Engineering (FEA), State University of Campinas (UNICAMP), Campinas, Brazil
| | - Amanda Silva de Sousa
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
| | - Edvaldo Rodrigo Morais
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil.,Faculty of Food Engineering (FEA), State University of Campinas (UNICAMP), Campinas, Brazil
| | - Cintia Regina Sargo
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
| | - Leticia Maria Zanphorlin
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
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Intasian P, Prakinee K, Phintha A, Trisrivirat D, Weeranoppanant N, Wongnate T, Chaiyen P. Enzymes, In Vivo Biocatalysis, and Metabolic Engineering for Enabling a Circular Economy and Sustainability. Chem Rev 2021; 121:10367-10451. [PMID: 34228428 DOI: 10.1021/acs.chemrev.1c00121] [Citation(s) in RCA: 63] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Since the industrial revolution, the rapid growth and development of global industries have depended largely upon the utilization of coal-derived chemicals, and more recently, the utilization of petroleum-based chemicals. These developments have followed a linear economy model (produce, consume, and dispose). As the world is facing a serious threat from the climate change crisis, a more sustainable solution for manufacturing, i.e., circular economy in which waste from the same or different industries can be used as feedstocks or resources for production offers an attractive industrial/business model. In nature, biological systems, i.e., microorganisms routinely use their enzymes and metabolic pathways to convert organic and inorganic wastes to synthesize biochemicals and energy required for their growth. Therefore, an understanding of how selected enzymes convert biobased feedstocks into special (bio)chemicals serves as an important basis from which to build on for applications in biocatalysis, metabolic engineering, and synthetic biology to enable biobased processes that are greener and cleaner for the environment. This review article highlights the current state of knowledge regarding the enzymatic reactions used in converting biobased wastes (lignocellulosic biomass, sugar, phenolic acid, triglyceride, fatty acid, and glycerol) and greenhouse gases (CO2 and CH4) into value-added products and discusses the current progress made in their metabolic engineering. The commercial aspects and life cycle assessment of products from enzymatic and metabolic engineering are also discussed. Continued development in the field of metabolic engineering would offer diversified solutions which are sustainable and renewable for manufacturing valuable chemicals.
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Affiliation(s)
- Pattarawan Intasian
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Rayong 21210, Thailand
| | - Kridsadakorn Prakinee
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Rayong 21210, Thailand
| | - Aisaraphon Phintha
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Rayong 21210, Thailand.,Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Duangthip Trisrivirat
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Rayong 21210, Thailand
| | - Nopphon Weeranoppanant
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Rayong 21210, Thailand.,Department of Chemical Engineering, Faculty of Engineering, Burapha University, 169, Long-hard Bangsaen, Saensook, Muang, Chonburi 20131, Thailand
| | - Thanyaporn Wongnate
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Rayong 21210, Thailand
| | - Pimchai Chaiyen
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Rayong 21210, Thailand
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Abstract
This study investigates the feasibility of producing ethanol from date palm seeds. The chemical compositions of three varieties of date seeds were first studied, showing mainly the presence of cellulose and hemicellulose. Ethanol was produced after a pre-treatment of date seeds using acid hydrolysis to extract the cellulosic fraction and to remove the lignin. Producing ethanol by fermentation was performed using the yeast Saccharomyces cerevisiae for 24 h, during which ethanol yield, biomass concentration, and total reducing sugars were recorded. The results obtained showed that the sugar content decreased over time, while ethanol production increased. Indeed, date seeds gave the highest ethanol concentration of 21.57 g/L after 6 h of alcoholic fermentation. These findings proved the feasibility of producing ethanol from date seeds.
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Sharma S, Arora A. Tracking strategic developments for conferring xylose utilization/fermentation by Saccharomyces cerevisiae. ANN MICROBIOL 2020. [DOI: 10.1186/s13213-020-01590-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Abstract
Purpose
Efficient ethanol production through lignocellulosic biomass hydrolysates could solve energy crisis as it is economically sustainable and ecofriendly. Saccharomyces cerevisiae is the work horse for lignocellulosic bioethanol production at industrial level. But its inability to ferment and utilize xylose limits the overall efficacy of the process.
Method
Data for the review was selected using different sources, such as Biofuels digest, Statista, International energy agency (IEA). Google scholar was used as a search engine to search literature for yeast metabolic engineering approaches. Keywords used were metabolic engineering of yeast for bioethanol production from lignocellulosic biomass.
Result
Through these approaches, interconnected pathways can be targeted randomly. Moreover, the improved strains genetic makeup can help us understand the mechanisms involved for this purpose.
Conclusion
This review discusses all possible approaches for metabolic engineering of yeast. These approaches may reveal unknown hidden mechanisms and construct ways for the researchers to produce novel and modified strains.
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Fatima B, Javed MM. Production, purification and physicochemical characterization of D-xylose/glucose isomerase from Escherichia coli strain BL21. 3 Biotech 2020; 10:39. [PMID: 31988833 DOI: 10.1007/s13205-019-2036-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 12/23/2019] [Indexed: 10/25/2022] Open
Abstract
Cell lysate of Escherichia coli strain BL21 showed significant D-glucose isomerase activity. The rate of glucose conversion was increased up to 40% when cells were induced with 1% D-xylose. E. coli BL21 xylose isomerase (ECXI-BL21) was purified to homogeneity, up to 1.9-fold with overall 10.88% enzyme yield by heat shock, salting out and electro-elution. The molecular mass of ECXI-BL21 was estimated as 43.9 kDa on SDS-PAGE. pHopt. and Topt. of the enzyme were calculated as 7.0 and 50 °C, respectively. Activation energy (E a) of ECXI-BL21 was 45 kJ/mol. Enzyme was stable from 30 to 55 °C and at pH range 6.0-8.0. ECXI-BL21(holo) was activated by 10 mM magnesium (35%), 0.5 mM cobalt (20%) and manganese (25%), and 0.5/10 mM Mn2+/Mg2+ (50%) and Co2+/Mg2+ (30%) as compared to ECXI-BL21(apo). Catalytic affinity (K m) of ECXI-BL21 for D-glucose was calculated as 0.82 mM, while maximum velocity (V max) of the reaction D-glucose(aldo) ⇌ D-fructose(keto) was 108 μmol/mg/min. D-fructose formed was identified on silica gel plate. This thermophilic enzyme, T m = 75 °C, has great potential for high fructose syrup production used in food and soft drink industries.
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High Gravity Fermentation of Sugarcane Bagasse Hydrolysate by Saccharomyces pastorianus to Produce Economically Distillable Ethanol Concentrations: Necessity of Medium Components Examined. FERMENTATION-BASEL 2020. [DOI: 10.3390/fermentation6010008] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A major economic obstacle in lignocellulosic ethanol production is the low sugar concentrations in the hydrolysate and subsequent fermentation to economically distillable ethanol concentrations. We have previously demonstrated a two-stage fermentation process that recycles xylose with xylose isomerase to increase ethanol productivity, where the low sugar concentrations in the hydrolysate limit the final ethanol concentrations. In this study, three approaches are combined to increase ethanol concentrations. First, the medium-additive requirements were investigated to reduce ethanol dilution. Second, methods to increase the sugar concentrations in the sugarcane bagasse hydrolysate were undertaken. Third, the two-stage fermentation process was recharacterized with high gravity hydrolysate. It was determined that phosphate and magnesium sulfate are essential to the ethanol fermentation. Additionally, the Escherichia coli extract and xylose isomerase additions were shown to significantly increase ethanol productivity. Finally, the fermentation on hydrolysate had only slightly lower productivity than the reagent-grade sugar fermentation; however, both fermentations had similar final ethanol concentrations. The present work demonstrates the capability to produce ethanol from high gravity sugarcane bagasse hydrolysate using Saccharomyces pastorianus with low yeast inoculum in minimal medium. Moreover, ethanol productivities were on par with pilot-scale commercial starch-based facilities, even when the yeast biomass production stage was included.
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Wang W, Mittal A, Pilath H, Chen X, Tucker MP, Johnson DK. Simultaneous upgrading of biomass-derived sugars to HMF/furfural via enzymatically isomerized ketose intermediates. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:253. [PMID: 31673288 PMCID: PMC6815050 DOI: 10.1186/s13068-019-1595-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 10/16/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND Recently, exploring fermentative or chemical pathways that convert biomass-derived sugars to fuels/chemicals has attracted a lot of interest from many researchers. We are investigating a hydrocarbon pathway from mixed sugars via 5-hydroxymethyl furfural (HMF) and furfural intermediates. To achieve this goal, we must first convert glucose and xylose to HMF and furfural in favorable yields. Current processes to produce HMF/furfural generally involve the use of acid catalysts in biphasic systems or solvents such as ionic liquids. However, the yield from transforming glucose to HMF is lower than the yield of furfural from xylose. RESULTS In this study, we present an efficient chemical pathway simultaneously transforming glucose and xylose to HMF and furfural via ketose intermediates, i.e., fructose and xylulose, which were generated from glucose and xylose via enzymatic isomerization. In the enzymatic isomerization, by adding sodium borate to complex with the ketoses, xylose conversion reached equilibrium after 2 h with a conversion of 91% and glucose conversion reached 84% after 4 h. By enzymatically isomerizing the aldoses to ketoses, the following dehydration reactions to HMF and furfural could be performed at low process temperatures (i.e., 110-120 °C) minimizing the side reactions of the sugars and limiting the degradation of furfurals to humins and carboxylic acids. At 120 °C, pH 0.5, and 15 min reaction time, mixed ketose sugars were converted to HMF and furfural in yields of 77% and 96%, respectively (based on starting aldose concentrations). CONCLUSION Taken together, our results demonstrate that this combined biological and chemical process could be an effective pathway to simultaneously convert biomass-derived glucose and xylose to HMF and furfural, for use as intermediates in the production of hydrocarbons.
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Affiliation(s)
- Wei Wang
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Ashutosh Mittal
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Heidi Pilath
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Xiaowen Chen
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Melvin P. Tucker
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - David K. Johnson
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
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Patiño MA, Ortiz JP, Velásquez M, Stambuk BU. d-Xylose consumption by nonrecombinant Saccharomyces cerevisiae: A review. Yeast 2019; 36:541-556. [PMID: 31254359 DOI: 10.1002/yea.3429] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 06/02/2019] [Accepted: 06/21/2019] [Indexed: 01/24/2023] Open
Abstract
Xylose is the second most abundant sugar in nature. Its efficient fermentation has been considered as a critical factor for a feasible conversion of renewable biomass resources into biofuels and other chemicals. The yeast Saccharomyces cerevisiae is of exceptional industrial importance due to its excellent capability to ferment sugars. However, although S. cerevisiae is able to ferment xylulose, it is considered unable to metabolize xylose, and thus, a lot of research has been directed to engineer this yeast with heterologous genes to allow xylose consumption and fermentation. The analysis of the natural genetic diversity of this yeast has also revealed some nonrecombinant S. cerevisiae strains that consume or even grow (modestly) on xylose. The genome of this yeast has all the genes required for xylose transport and metabolism through the xylose reductase, xylitol dehydrogenase, and xylulokinase pathway, but there seems to be problems in their kinetic properties and/or required expression. Self-cloning industrial S. cerevisiae strains overexpressing some of the endogenous genes have shown interesting results, and new strategies and approaches designed to improve these S. cerevisiae strains for ethanol production from xylose will also be presented in this review.
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Affiliation(s)
- Margareth Andrea Patiño
- Instituto de Biotecnología.,Departamento de Ingeniería Química y Ambiental, Universidad Nacional de Colombia, Bogotá, Colombia
| | - Juan Pablo Ortiz
- Facultad de Ciencias e Ingeniería, Universidad de Boyacá, Tunja, Colombia
| | - Mario Velásquez
- Departamento de Ingeniería Química y Ambiental, Universidad Nacional de Colombia, Bogotá, Colombia
| | - Boris U Stambuk
- Departamento de Bioquímica, Universidad Federal de Santa Catarina, Florianópolis, Brazil
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11
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Mahalingam R. Temporal Analyses of Barley Malting Stages Using Shotgun Proteomics. Proteomics 2018; 18:e1800025. [DOI: 10.1002/pmic.201800025] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 06/08/2018] [Indexed: 01/08/2023]
Affiliation(s)
- Ramamurthy Mahalingam
- United States Department of Agriculture; Agricultural Research Service; Cereal Crops Research Unit; 502 Walnut Street 53726 Madison WI USA
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12
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Feng Q, Liu ZL, Weber SA, Li S. Signature pathway expression of xylose utilization in the genetically engineered industrial yeast Saccharomyces cerevisiae. PLoS One 2018; 13:e0195633. [PMID: 29621349 PMCID: PMC5886582 DOI: 10.1371/journal.pone.0195633] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 03/25/2018] [Indexed: 01/18/2023] Open
Abstract
Haploid laboratory strains of Saccharomyces cerevisiae are commonly used for genetic engineering to enable their xylose utilization but little is known about the industrial yeast which is often recognized as diploid and as well as haploid and tetraploid. Here we report three unique signature pathway expression patterns and gene interactions in the centre metabolic pathways that signify xylose utilization of genetically engineered industrial yeast S. cerevisiae NRRL Y-50463, a diploid yeast. Quantitative expression analysis revealed outstanding high levels of constitutive expression of YXI, a synthesized yeast codon-optimized xylose isomerase gene integrated into chromosome XV of strain Y-50463. Comparative expression analysis indicated that the YXI was necessary to initiate the xylose metabolic pathway along with a set of heterologous xylose transporter and utilization facilitating genes including XUT4, XUT6, XKS1 and XYL2. The highly activated transketolase and transaldolase genes TKL1, TKL2, TAL1 and NQM1 as well as their complex interactions in the non-oxidative pentose phosphate pathway branch were critical for the serial of sugar transformation to drive the metabolic flow into glycolysis for increased ethanol production. The significantly increased expression of the entire PRS gene family facilitates functions of the life cycle and biosynthesis superpathway for the yeast. The outstanding higher levels of constitutive expression of YXI and the first insight into the signature pathway expression and the gene interactions in the closely related centre metabolic pathways from the industrial yeast aid continued efforts for development of the next-generation biocatalyst. Our results further suggest the industrial yeast is a desirable delivery vehicle for new strain development for efficient lignocellulose-to-advanced biofuels production.
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Affiliation(s)
- Quanzhou Feng
- Bioenergy Research Unit, US Department of Agriculture, Agricultural Research Service, National Center for Agricultural Utilization Research, Peoria, IL, United States of America
- Institute of New Energy Technology, Tsinghua University, Haidian Qu, Beijing, China
| | - Z. Lewis Liu
- Bioenergy Research Unit, US Department of Agriculture, Agricultural Research Service, National Center for Agricultural Utilization Research, Peoria, IL, United States of America
- USDA-MOST Joint Research Center for Biofuels, Peoria, IL, United States of America
- * E-mail: (ZLL); (SL)
| | - Scott A. Weber
- Bioenergy Research Unit, US Department of Agriculture, Agricultural Research Service, National Center for Agricultural Utilization Research, Peoria, IL, United States of America
| | - Shizhong Li
- Institute of New Energy Technology, Tsinghua University, Haidian Qu, Beijing, China
- USDA-MOST Joint Research Center for Biofuels, Peoria, IL, United States of America
- * E-mail: (ZLL); (SL)
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Sharma S, Arora A, Sharma P, Singh S, Nain L, Paul D. Notable mixed substrate fermentation by native Kodamaea ohmeri strains isolated from Lagenaria siceraria flowers and ethanol production on paddy straw hydrolysates. Chem Cent J 2018; 12:8. [PMID: 29404706 PMCID: PMC5799091 DOI: 10.1186/s13065-018-0375-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 01/20/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Bioethanol obtained by fermenting cellulosic fraction of biomass holds promise for blending in petroleum. Cellulose hydrolysis yields glucose while hemicellulose hydrolysis predominantly yields xylose. Economic feasibility of bioethanol depends on complete utilization of biomass carbohydrates and an efficient co-fermenting organism is a prerequisite. While hexose fermentation capability of Saccharomyces cerevisiae is a boon, however, its inability to ferment pentose is a setback. RESULTS Two xylose fermenting Kodamaea ohmeri strains were isolated from Lagenaria siceraria flowers through enrichment on xylose. They showed 61% glucose fermentation efficiency in fortified medium. Medium engineering with 0.1% yeast extract and peptone, stimulated co-fermentation potential of both strains yielding maximum ethanol 0.25 g g-1 on mixed sugars with ~ 50% fermentation efficiency. Strains were tolerant to inhibitors like 5-hydroxymethyl furfural, furfural and acetic acid. Both K. ohmeri strains grew well on biologically pretreated rice straw hydrolysates and produced ethanol. CONCLUSIONS This is the first report of native Kodamaea sp. exhibiting notable mixed substrate utilization and ethanol fermentation. K. ohmeri strains showed relevant traits like utilizing and co-fermenting mixed sugars, exhibiting excellent growth, inhibitor tolerance, and ethanol production on rice straw hydrolysates.
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Affiliation(s)
- Shalley Sharma
- Division of Microbiology, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India
| | - Anju Arora
- Division of Microbiology, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India.
| | - Pankhuri Sharma
- Division of Microbiology, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India
| | - Surender Singh
- Division of Microbiology, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India
| | - Lata Nain
- Division of Microbiology, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India
| | - Debarati Paul
- Amity Institute of Biotechnology, Amity University, Noida, U.P., India
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14
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Martins GM, Bocchini-Martins DA, Bezzerra-Bussoli C, Pagnocca FC, Boscolo M, Monteiro DA, Silva RD, Gomes E. The isolation of pentose-assimilating yeasts and their xylose fermentation potential. Braz J Microbiol 2017; 49:162-168. [PMID: 28888830 PMCID: PMC5790582 DOI: 10.1016/j.bjm.2016.11.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 07/05/2016] [Accepted: 11/13/2016] [Indexed: 11/19/2022] Open
Abstract
For the implementation of cellulosic ethanol technology, the maximum use of lignocellulosic materials is important to increase efficiency and to reduce costs. In this context, appropriate use of the pentose released by hemicellulose hydrolysis could improve de economic viability of this process. Since the Saccharomyces cerevisiae is unable to ferment the pentose, the search for pentose-fermenting microorganisms could be an alternative. In this work, the isolation of yeast strains from decaying vegetal materials, flowers, fruits and insects and their application for assimilation and alcoholic fermentation of xylose were carried out. From a total of 30 isolated strains, 12 were able to assimilate 30 g L−1 of xylose in 120 h. The strain Candida tropicalis S4 produced 6 g L−1 of ethanol from 56 g L−1 of xylose, while the strain C. tropicalis E2 produced 22 g L−1 of xylitol. The strains Candida oleophila G10.1 and Metschnikowia koreensis G18 consumed significant amount of xylose in aerobic cultivation releasing non-identified metabolites. The different materials in environment were source for pentose-assimilating yeast with variable metabolic profile.
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Affiliation(s)
- Gisele Marta Martins
- Universidade Estadual Paulista(UNESP), Instituto de Pesquisa em Bioenergia-IPBen, Laboratório de Microbiologia aplicada, São José do Rio Preto, SP, Brazil
| | | | - Carolina Bezzerra-Bussoli
- Universidade Estadual Paulista(UNESP), Instituto de Pesquisa em Bioenergia-IPBen, Laboratório de Microbiologia aplicada, São José do Rio Preto, SP, Brazil
| | - Fernando Carlos Pagnocca
- Universidade Estadual Paulista-UNESP, Centro de Estudos de Insetos Sociais-Ceis, Campus of Rio Claro, SP, Brazil
| | - Maurício Boscolo
- Universidade Estadual Paulista(UNESP), Instituto de Pesquisa em Bioenergia-IPBen, Laboratório de Microbiologia aplicada, São José do Rio Preto, SP, Brazil
| | - Diego Alves Monteiro
- Universidade Estadual Paulista(UNESP), Instituto de Pesquisa em Bioenergia-IPBen, Laboratório de Microbiologia aplicada, São José do Rio Preto, SP, Brazil
| | - Roberto da Silva
- Universidade Estadual Paulista(UNESP), Instituto de Pesquisa em Bioenergia-IPBen, Laboratório de Microbiologia aplicada, São José do Rio Preto, SP, Brazil
| | - Eleni Gomes
- Universidade Estadual Paulista(UNESP), Instituto de Pesquisa em Bioenergia-IPBen, Laboratório de Microbiologia aplicada, São José do Rio Preto, SP, Brazil.
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15
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Abstract
Cells grow on a wide range of carbon sources by regulating substrate flow through the metabolic network. Incoming sugar, for example, can be fermented or respired, depending on the carbon identity, cell type, or growth conditions. Despite this genetically-encoded flexibility of carbon metabolism, attempts to exogenously manipulate central carbon flux by rational design have proven difficult, suggesting a robust network structure. To examine this robustness, we characterized the ethanol yield of 411 regulatory and metabolic mutants in budding yeast. The mutants showed little variation in ethanol productivity when grown on glucose or galactose, yet diversity was revealed during growth on xylulose, a rare pentose not widely available in nature. While producing ethanol at high yield, cells grown on xylulose produced ethanol at high yields, yet induced expression of respiratory genes, and were dependent on them. Analysis of mutants that affected ethanol productivity suggested that xylulose fermentation results from metabolic overflow, whereby the flux through glycolysis is higher than the maximal flux that can enter respiration. We suggest that this overflow results from a suboptimal regulatory adjustment of the cells to this unfamiliar carbon source.
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16
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Lajoie CA, Kitner JB, Potochnik SJ, Townsend JM, Beatty CC, Kelly CJ. Cloning, expression and characterization of xylose isomerase from the marine bacteriumFulvimarina pelagiinEscherichia coli. Biotechnol Prog 2016; 32:1230-1237. [DOI: 10.1002/btpr.2309] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 04/27/2016] [Indexed: 01/08/2023]
Affiliation(s)
- Curtis A. Lajoie
- School of Chemical, Biological, and Environmental Engineering; Oregon State University; 101 Covell Hall Corvallis OR 97331-2701
| | - Joshua B. Kitner
- Trillium FiberFuels, Inc.; 720 NE Granger Ave. Corvallis OR 97330-9660
| | | | - Jakob M. Townsend
- School of Chemical, Biological, and Environmental Engineering; Oregon State University; 101 Covell Hall Corvallis OR 97331-2701
| | | | - Christine J. Kelly
- School of Chemical, Biological, and Environmental Engineering; Oregon State University; 101 Covell Hall Corvallis OR 97331-2701
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dos Santos LV, de Barros Grassi MC, Gallardo JCM, Pirolla RAS, Calderón LL, de Carvalho-Netto OV, Parreiras LS, Camargo ELO, Drezza AL, Missawa SK, Teixeira GS, Lunardi I, Bressiani J, Pereira GAG. Second-Generation Ethanol: The Need is Becoming a Reality. Ind Biotechnol (New Rochelle N Y) 2016. [DOI: 10.1089/ind.2015.0017] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
| | | | | | | | - Luige Llerena Calderón
- GranBio/BioCelere, Campinas, Brazil
- Laboratório de Genômica e Expressão, UNICAMP, Campinas, Brazil
| | | | - Lucas Salera Parreiras
- GranBio/BioCelere, Campinas, Brazil
- Laboratório de Genômica e Expressão, UNICAMP, Campinas, Brazil
| | | | | | - Sílvia Kazue Missawa
- GranBio/BioCelere, Campinas, Brazil
- Laboratório de Genômica e Expressão, UNICAMP, Campinas, Brazil
| | - Gleidson Silva Teixeira
- GranBio/BioCelere, Campinas, Brazil
- Laboratório de Genômica e Expressão, UNICAMP, Campinas, Brazil
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Shalley Sharma, Sonia Sharma, Surender Singh, Lata, Anju Arora. Improving Yeast Strains for Pentose Hexose Co-fermentation: Successes and Hurdles. SPRINGER PROCEEDINGS IN ENERGY 2016. [DOI: 10.1007/978-81-322-2773-1_3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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19
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Research Progress Concerning Fungal and Bacterial β-Xylosidases. Appl Biochem Biotechnol 2015; 178:766-95. [DOI: 10.1007/s12010-015-1908-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 10/22/2015] [Indexed: 01/08/2023]
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20
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Paulova L, Patakova P, Branska B, Rychtera M, Melzoch K. Lignocellulosic ethanol: Technology design and its impact on process efficiency. Biotechnol Adv 2015; 33:1091-107. [DOI: 10.1016/j.biotechadv.2014.12.002] [Citation(s) in RCA: 117] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 12/01/2014] [Accepted: 12/03/2014] [Indexed: 12/27/2022]
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21
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Hohenschuh W, Hector R, Murthy GS. A dynamic flux balance model and bottleneck identification of glucose, xylose, xylulose co-fermentation in Saccharomyces cerevisiae. BIORESOURCE TECHNOLOGY 2015; 188:153-160. [PMID: 25791332 DOI: 10.1016/j.biortech.2015.02.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 02/04/2015] [Accepted: 02/05/2015] [Indexed: 06/04/2023]
Abstract
A combination of batch fermentations and genome scale flux balance analysis were used to identify and quantify the rate limiting reactions in the xylulose transport and utilization pathway. Xylulose phosphorylation by xylulokinase was identified as limiting in wild type Saccharomyces cerevisiae, but transport became limiting when xylulokinase was upregulated. Further experiments showed xylulose transport through the HXT family of non-specific glucose transporters. A genome scale flux balance model was developed which included an improved variable sugar uptake constraint controlled by HXT expression. Model predictions closely matched experimental xylulose utilization rates suggesting the combination of transport and xylulokinase constraints is sufficient to explain xylulose utilization limitation in S. cerevisiae.
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22
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Mahajan C, Chadha BS, Nain L, Kaur A. Evaluation of glycosyl hydrolases from thermophilic fungi for their potential in bioconversion of alkali and biologically treated Parthenium hysterophorus weed and rice straw into ethanol. BIORESOURCE TECHNOLOGY 2014; 163:300-7. [PMID: 24835742 DOI: 10.1016/j.biortech.2014.04.057] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 04/16/2014] [Accepted: 04/18/2014] [Indexed: 05/06/2023]
Abstract
The aim of this work was to evaluate glycosyl hydrolases produced by diverse thermophilic fungal strains for saccharification of alkali and biologically (Trametes hirusita/Myrothecium roridum) treated Parthenium hysterophorus and rice straw. The compositional analysis of hydrolysates by HPLC showed distinct profiles of hexose, pentose and oligomeric sugars. Malbranchea cinnamomea was most efficient source of glycosyl hydrolases producing 283.8, 35.9, 129.6, 27,193, 4.66, 7.26(units/gds) of endoglucanase, cellobiohydrolase, β-glucosidase, xylanase, α-αrabinofuranosidase and β xylosidase, respectively. The saccharification of alkali and biologically treated carrot grass by culture extract of M. cinnamomea was further enhanced by supplementation of β-glucosidase produced by Aspergillus sp. mutant "O". The resultant hydrolysates containing glucose/xylose were fermented efficiently to ethanol by Saccharomyces cerevisiae owing to presence of xylose isomerase (0.8 units/gds) activity in culture extract of M. cinnamomea resulting in production of 16.5 and 15.0 g/l of ethanol from alkali treated rice straw and carrot grass, respectively.
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Affiliation(s)
- Chhavi Mahajan
- Department of Microbiology, Guru Nanak Dev University, Amritsar 143005, Punjab, India.
| | - B S Chadha
- Department of Microbiology, Guru Nanak Dev University, Amritsar 143005, Punjab, India.
| | - Lata Nain
- Department of Microbiology, Indian Agricultural Research Institute, New Delhi 110012, India.
| | - Amarjeet Kaur
- Department of Microbiology, Guru Nanak Dev University, Amritsar 143005, Punjab, India.
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23
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Colabardini AC, Ries LNA, Brown NA, dos Reis TF, Savoldi M, Goldman MHS, Menino JF, Rodrigues F, Goldman GH. Functional characterization of a xylose transporter in Aspergillus nidulans. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:46. [PMID: 24690493 PMCID: PMC4021826 DOI: 10.1186/1754-6834-7-46] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Accepted: 03/13/2014] [Indexed: 05/06/2023]
Abstract
BACKGROUND The production of bioethanol from lignocellulosic feedstocks will only become economically feasible when the majority of cellulosic and hemicellulosic biopolymers can be efficiently converted into bioethanol. The main component of cellulose is glucose, whereas hemicelluloses mainly consist of pentose sugars such as D-xylose and L-arabinose. The genomes of filamentous fungi such as A. nidulans encode a multiplicity of sugar transporters with broad affinities for hexose and pentose sugars. Saccharomyces cerevisiae, which has a long history of use in industrial fermentation processes, is not able to efficiently transport or metabolize pentose sugars (e.g. xylose). Subsequently, the aim of this study was to identify xylose-transporters from A. nidulans, as potential candidates for introduction into S. cerevisiae in order to improve xylose utilization. RESULTS In this study, we identified the A. nidulans xtrD (xylose transporter) gene, which encodes a Major Facilitator Superfamily (MFS) transporter, and which was specifically induced at the transcriptional level by xylose in a XlnR-dependent manner, while being partially repressed by glucose in a CreA-dependent manner. We evaluated the ability of xtrD to functionally complement the S. cerevisiae EBY.VW4000 strain which is unable to grow on glucose, fructose, mannose or galactose as single carbon source. In S. cerevisiae, XtrD was targeted to the plasma membrane and its expression was able to restore growth on xylose, glucose, galactose, and mannose as single carbon sources, indicating that this transporter accepts multiple sugars as a substrate. XtrD has a high affinity for xylose, and may be a high affinity xylose transporter. We were able to select a S. cerevisiae mutant strain that had increased xylose transport when expressing the xtrD gene. CONCLUSIONS This study characterized the regulation and substrate specificity of an A. nidulans transporter that represents a good candidate for further directed mutagenesis. Investigation into the area of sugar transport in fungi presents a crucial step for improving the S. cerevisiae xylose metabolism. Moreover, we have demonstrated that the introduction of adaptive mutations beyond the introduced xylose utilization genes is able to improve S. cerevisiae xylose metabolism.
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Affiliation(s)
- Ana Cristina Colabardini
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café S/N, CEP 14040-903 Ribeirão Preto, São Paulo, Brazil
| | - Laure Nicolas Annick Ries
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café S/N, CEP 14040-903 Ribeirão Preto, São Paulo, Brazil
| | - Neil Andrew Brown
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café S/N, CEP 14040-903 Ribeirão Preto, São Paulo, Brazil
| | - Thaila Fernanda dos Reis
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café S/N, CEP 14040-903 Ribeirão Preto, São Paulo, Brazil
| | - Marcela Savoldi
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café S/N, CEP 14040-903 Ribeirão Preto, São Paulo, Brazil
| | - Maria Helena S Goldman
- Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - João Filipe Menino
- ICVS/3B’s - PT Government Associate Laboratory, Braga/Guimarães, Portugal and Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal
| | - Fernando Rodrigues
- ICVS/3B’s - PT Government Associate Laboratory, Braga/Guimarães, Portugal and Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal
| | - Gustavo Henrique Goldman
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café S/N, CEP 14040-903 Ribeirão Preto, São Paulo, Brazil
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol – CTBE, Caixa Postal 6170 13083-970, Campinas, São Paulo, Brazil
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24
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Gowtham YK, Miller KP, Hodge DB, Henson JM, Harcum SW. Novel two-stage fermentation process for bioethanol production usingSaccharomyces pastorianus. Biotechnol Prog 2014; 30:300-10. [DOI: 10.1002/btpr.1850] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2013] [Revised: 12/03/2013] [Indexed: 12/15/2022]
Affiliation(s)
- Yogender Kumar Gowtham
- Dept. of Bioengineering; Clemson University; 301 Rhodes Research Center; Clemson SC 29634
| | | | - David B. Hodge
- Dept. of Chemical Engineering and Materials Science; Michigan State University; East Lansing MI 48824
- Dept. of Biosystems & Agricultural Engineering; Michigan State University; East Lansing MI 48824
- DOE Great Lakes Bioenergy Research Center; Michigan State University; East Lansing MI 48824
- Dept. of Civil; Environmental and Natural Resource Engineering, Luleå University of Technology; Luleå 97752 Sweden
| | | | - Sarah W. Harcum
- Dept. of Bioengineering; Clemson University; 301 Rhodes Research Center; Clemson SC 29634
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25
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Waltman MJ, Yang ZK, Langan P, Graham DE, Kovalevsky A. Engineering acidic Streptomyces rubiginosus D-xylose isomerase by rational enzyme design. Protein Eng Des Sel 2014; 27:59-64. [PMID: 24402330 DOI: 10.1093/protein/gzt062] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
To maximize bioethanol production from lignocellulosic biomass, all sugars must be utilized. Yeast fermentation can be improved by introducing the d-xylose isomerase enzyme to convert the pentose sugar d-xylose, which cannot be fermented by Saccharomyces cerevisiae, into the fermentable ketose d-xylulose. The low activity of d-xylose isomerase, especially at the low pH required for optimal fermentation, limits its use. A rational enzyme engineering approach was undertaken, and seven amino acid positions were replaced to improve the activity of Streptomyces rubiginosus d-xylose isomerase towards its physiological substrate at pH values below 6. The active-site design was guided by mechanistic insights and the knowledge of amino acid protonation states at low pH obtained from previous joint X-ray/neutron crystallographic experiments. Tagging the enzyme with 6 or 12 histidine residues at the N-terminus resulted in a significant increase in the active-site affinity towards substrate at pH 5.8. Substituting an asparagine at position 215, which hydrogen bonded to the metal-bound Glu181 and Asp245, with an aspartate gave a variant with almost an order of magnitude lower KM than measured for the native enzyme, with a 4-fold increase in activity. Other studied variants showed similar (Asp57Asn, Glu186Gln/Asn215Asp), lower (Asp57His, Asn247Asp, Lys289His, Lys289Glu) or no (Gln256Asp, Asp287Asn, ΔAsp287) activity in acidic conditions relative to the native enzyme.
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Affiliation(s)
- Mary Jo Waltman
- Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
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26
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Li Z, Qu H, Li C, Zhou X. Direct and efficient xylitol production from xylan by Saccharomyces cerevisiae through transcriptional level and fermentation processing optimizations. BIORESOURCE TECHNOLOGY 2013; 149:413-419. [PMID: 24128404 DOI: 10.1016/j.biortech.2013.09.101] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 09/19/2013] [Accepted: 09/22/2013] [Indexed: 05/27/2023]
Abstract
In this study, four engineered Saccharomyces cerevisiae carrying xylanase, β-xylosidase and xylose reductase genes by different transcriptional regulations were constructed to directly convert xylan to xylitol. According to the results, the high-copy number plasmid required a rigid selection for promoter characteristics, on the contrast, the selection of promoters could be more flexible for low-copy number plasmid. For cell growth and xylitol production, glucose and galactose were found more efficient than other sugars. The semi-aerobic condition and feeding of co-substrates were taken to improve the yield of xylitol. It was found that the strain containing high-copy number plasmid had the highest xylitol yield, but it was sensitive to the change of fermentation. However, the strain carrying low-copy number plasmid was more adaptable to different processes. By optimization of the transcriptional regulation and fermentation processes, the xylitol concentration could be increased of 1.7 folds and the yield was 0.71 g xylitol/g xylan.
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Affiliation(s)
- Zhe Li
- School of Life Science, Beijing Institute of Technology, Beijing 100081, PR China
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27
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Atkinson B. TECHNICAL OPPORTUNITIES FOR MALTING AND BREWING IN THE ′90's*. JOURNAL OF THE INSTITUTE OF BREWING 2013. [DOI: 10.1002/j.2050-0416.1988.tb04583.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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28
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Miller KP, Gowtham YK, Henson JM, Harcum SW. Xylose isomerase improves growth and ethanol production rates from biomass sugars for both Saccharomyces pastorianus and Saccharomyces cerevisiae. Biotechnol Prog 2012; 28:669-80. [PMID: 22866331 DOI: 10.1002/btpr.1535] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The demand for biofuel ethanol made from clean, renewable nonfood sources is growing. Cellulosic biomass, such as switch grass (Panicum virgatum L.), is an alternative feedstock for ethanol production; however, cellulosic feedstock hydrolysates contain high levels of xylose, which needs to be converted to ethanol to meet economic feasibility. In this study, the effects of xylose isomerase on cell growth and ethanol production from biomass sugars representative of switch grass were investigated using low cell density cultures. The lager yeast species Saccharomyces pastorianus was grown with immobilized xylose isomerase in the fermentation step to determine the impact of the glucose and xylose concentrations on the ethanol production rates. Ethanol production rates were improved due to xylose isomerase; however, the positive effect was not due solely to the conversion of xylose to xylulose. Xylose isomerase also has glucose isomerase activity, so to better understand the impact of the xylose isomerase on S. pastorianus, growth and ethanol production were examined in cultures provided fructose as the sole carbon. It was observed that growth and ethanol production rates were higher for the fructose cultures with xylose isomerase even in the absence of xylose. To determine whether the positive effects of xylose isomerase extended to other yeast species, a side-by-side comparison of S. pastorianus and Saccharomyces cerevisiae was conducted. These comparisons demonstrated that the xylose isomerase increased ethanol productivity for both the yeast species by increasing the glucose consumption rate. These results suggest that xylose isomerase can contribute to improved ethanol productivity, even without significant xylose conversion.
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Affiliation(s)
- Kristen P Miller
- Department of Bioengineering, Clemson University, Clemson, SC 29634, USA
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29
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Detroy RW, Cunningham RL, Bothast RJ, Bagby MO, Herman A. Bioconversion of wheat straw cellulose/hemicellulose to ethanol by Saccharomyces uvarum and Pachysolen tannophilus. Biotechnol Bioeng 2012; 24:1105-13. [PMID: 18546403 DOI: 10.1002/bit.260240507] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The information presented in this publication represents current research findings on the production of glucose and xylose from straw and subsequent direct fermentation of both sugars to ethanol. Agricultural straw was subjected to thermal or alkali pulping prior to enzymatic saccharification. When wheat straw (WS) was treated at 170 degrees C for 30-60 min at a water-to-solids ratio of 7:1, the yield of cellulosic pulp was 70-82%. A sodium hydroxide extration yielded a 60% cellulosic pulp and a hemicellulosic fraction available for fermentation to ethanol. The cellulosic pulps were subjected to cellulase hydrolysis at 55 degrees C for production of sugars to support a 6-C fermentation. Hemicellulose was recovered from the liquor filtrates by acid/alcohol precipitation followed by acid hydrolysis to xylose for fermentation. Subsequent experiments have involved the fermentation of cellulosic and hemicelluosic hydrolysates to ethanol. Apparently these fermentations were inhibited by substances introduced by thermal and alkali treatment of the straws, because ethanol efficiencies of only 40-60% were achieved. Xylose from hydrolysis of wheat straw pentosans supported an ethanol fermentation by Pachysolen tannophilus strain NRRL 2460. This unusual yeast is capable of producing ethanol from both glucose and xylose. Ethanol yields were not maximal due to deleterious substances in the WS hydrolysates.
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Affiliation(s)
- R W Detroy
- Northern Regional Research Center, Agricultural Research Science and Education Administration, U. S. Department of Agriculture, Peoria, Illinois 61604
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30
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Yuan D, Rao K, Varanasi S, Relue P. A viable method and configuration for fermenting biomass sugars to ethanol using native Saccharomyces cerevisiae. BIORESOURCE TECHNOLOGY 2012; 117:92-98. [PMID: 22609719 DOI: 10.1016/j.biortech.2012.04.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 04/02/2012] [Accepted: 04/03/2012] [Indexed: 06/01/2023]
Abstract
A system that incorporates a packed bed reactor for isomerization of xylose and a hollow fiber membrane fermentor (HFMF) for sugar fermentation by yeast was developed for facile recovery of the xylose isomerase enzyme pellets and reuse of the cartridge loaded with yeast. Fermentation of pre-isomerized poplar hydrolysate produced using ionic liquid pretreatment in HFMF resulted in ethanol yields equivalent to that of model sugar mixtures of xylose and glucose. By recirculating model sugar mixtures containing partially isomerized xylose through the packed bed and the HFMF connected in series, 39 g/l ethanol was produced within 10h with 86.4% xylose utilization. The modular nature of this configuration has the potential for easy scale-up of the simultaneous isomerization and fermentation process without significant capital costs.
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Affiliation(s)
- Dawei Yuan
- Department of Bioengineering, 1610 N. Westwood Ave. MS 303, University of Toledo, Toledo, OH 43606, USA
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31
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Umemoto Y, Shibata T, Araki T. D-xylose isomerase from a marine bacterium, Vibrio sp. strain XY-214, and D-xylulose production from β-1,3-xylan. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2012; 14:10-20. [PMID: 21519808 DOI: 10.1007/s10126-011-9380-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Accepted: 03/16/2011] [Indexed: 05/30/2023]
Abstract
The xylA gene from a marine bacterium, Vibrio sp. strain XY-214, encoding D-xylose isomerase (XylA) was cloned and expressed in Escherichia coli. The xylA gene consisted of 1,320-bp nucleotides encoding a protein of 439 amino acids with a predicted molecular weight of 49,264. XylA was classified into group II xylose isomerases. The native XylA was estimated to be a homotetramer with a molecular mass of 190 kDa. The purified recombinant XylA exhibited maximal activity at 60°C and pH 7.5. Its apparent K (m) values for D-xylose and D-glucose were 7.93 and 187 mM, respectively. Furthermore, we carried out D-xylulose production from β-1,3-xylan, a major cell wall polysaccharide component of the killer alga Caulerpa taxifolia. The synergistic action of β-1,3-xylanase (TxyA) and β-1,3-xylosidase (XloA) from Vibrio sp. strain XY-214 enabled efficient saccharification of β-1,3-xylan to D-xylose. D-xylose was then converted to D-xylulose by using XylA from the strain XY-214. The conversion rate of D-xylose to D-xylulose by XylA was found to be approximately 40% in the presence of 4 mM sodium tetraborate after 2 h of incubation. These results demonstrated that TxyA, XloA, and XylA from Vibrio sp. strain XY-214 are useful tools for D-xylulose production from β-1,3-xylan. Because D-xylulose can be used as a source for ethanol fermentation by yeast Saccharomyces cerevisiae, the present study will provide a basis for ethanol production from β-1,3-xylan.
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Affiliation(s)
- Yoshiaki Umemoto
- Laboratory for the Utilization of Aquatic Bioresources, Department of Life Science, Graduate School of Bioresources, Mie University, 1577 Kurimamachiya, Tsu, Mie 514-8507, Japan
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32
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Yuan D, Rao K, Relue P, Varanasi S. Fermentation of biomass sugars to ethanol using native industrial yeast strains. BIORESOURCE TECHNOLOGY 2011; 102:3246-3253. [PMID: 21129954 DOI: 10.1016/j.biortech.2010.11.034] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Revised: 11/07/2010] [Accepted: 11/09/2010] [Indexed: 05/30/2023]
Abstract
In this paper, the feasibility of a technology for fermenting sugar mixtures representative of cellulosic biomass hydrolyzates with native industrial yeast strains is demonstrated. This paper explores the isomerization of xylose to xylulose using a bi-layered enzyme pellet system capable of sustaining a micro-environmental pH gradient. This ability allows for considerable flexibility in conducting the isomerization and fermentation steps. With this method, the isomerization and fermentation could be conducted sequentially, in fed-batch, or simultaneously to maximize utilization of both C5 and C6 sugars and ethanol yield. This system takes advantage of a pH-dependent complexation of xylulose with a supplemented additive to achieve up to 86% isomerization of xylose at fermentation conditions. Commercially-proven Saccharomyces cerevisiae strains from the corn-ethanol industry were used and shown to be very effective in implementation of the technology for ethanol production.
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Affiliation(s)
- Dawei Yuan
- Department of Bioengineering, University of Toledo, Toledo, OH 43606, USA
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33
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Madhavan A, Srivastava A, Kondo A, Bisaria VS. Bioconversion of lignocellulose-derived sugars to ethanol by engineered Saccharomyces cerevisiae. Crit Rev Biotechnol 2011; 32:22-48. [PMID: 21204601 DOI: 10.3109/07388551.2010.539551] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Lignocellulosic biomass from agricultural and agro-industrial residues represents one of the most important renewable resources that can be utilized for the biological production of ethanol. The yeast Saccharomyces cerevisiae is widely used for the commercial production of bioethanol from sucrose or starch-derived glucose. While glucose and other hexose sugars like galactose and mannose can be fermented to ethanol by S. cerevisiae, the major pentose sugars D-xylose and L-arabinose remain unutilized. Nevertheless, D-xylulose, the keto isomer of xylose, can be fermented slowly by the yeast and thus, the incorporation of functional routes for the conversion of xylose and arabinose to xylulose or xylulose-5-phosphate in Saccharomyces cerevisiae can help to improve the ethanol productivity and make the fermentation process more cost-effective. Other crucial bottlenecks in pentose fermentation include low activity of the pentose phosphate pathway enzymes and competitive inhibition of xylose and arabinose transport into the cell cytoplasm by glucose and other hexose sugars. Along with a brief introduction of the pretreatment of lignocellulose and detoxification of the hydrolysate, this review provides an updated overview of (a) the key steps involved in the uptake and metabolism of the hexose sugars: glucose, galactose, and mannose, together with the pentose sugars: xylose and arabinose, (b) various factors that play a major role in the efficient fermentation of pentose sugars along with hexose sugars, and (c) the approaches used to overcome the metabolic constraints in the production of bioethanol from lignocellulose-derived sugars by developing recombinant S. cerevisiae strains.
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Affiliation(s)
- Anjali Madhavan
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India
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34
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Kasumi T, Mori S, Kaneko S, Koyama Y. Molecular Cloning and Characterization of D-Xylose Isomerase from A Novel Actinobacteria, Thermobifida fusca MBL 10003. J Appl Glycosci (1999) 2011. [DOI: 10.5458/jag.jag.jag-2011_014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022] Open
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35
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Chen X, Jiang ZH, Chen S, Qin W. Microbial and bioconversion production of D-xylitol and its detection and application. Int J Biol Sci 2010; 6:834-44. [PMID: 21179590 PMCID: PMC3005349 DOI: 10.7150/ijbs.6.834] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Accepted: 12/06/2010] [Indexed: 11/22/2022] Open
Abstract
D-Xylitol is found in low content as a natural constituent of many fruits and vegetables. It is a five-carbon sugar polyol and has been used as a food additive and sweetening agent to replace sucrose, especially for non-insulin dependent diabetics. It has multiple beneficial health effects, such as the prevention of dental caries, and acute otitis media. In industry, it has been produced by chemical reduction of D-xylose mainly from photosynthetic biomass hydrolysates. As an alternative method of chemical reduction, biosynthesis of D-xylitol has been focused on the metabolically engineered Saccharomyces cerevisiae and Candida strains. In order to detect D-xylitol in the production processes, several detection methods have been established, such as gas chromatography (GC)-based methods, high performance liquid chromatography (HPLC)-based methods, LC-MS methods, and capillary electrophoresis methods (CE). The advantages and disadvantages of these methods are compared in this review.
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Affiliation(s)
- Xi Chen
- Biorefining Research Initiative and Department of Biology, Lakehead University, Thunder Bay, ON P7B 5E1, Canada
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Chiang LC, Gong CS, Chen LF, Tsao GT. d-Xylulose Fermentation to Ethanol by Saccharomyces cerevisiae. Appl Environ Microbiol 2010; 42:284-9. [PMID: 16345828 PMCID: PMC244003 DOI: 10.1128/aem.42.2.284-289.1981] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We used commercial bakers' yeast (Saccharomyces cerevisiae) to study the conversion of d-xylulose to ethanol in the presence of d-xylose. The rate of ethanol production increased with an increase in yeast cell density. The optimal temperature for d-xylulose fermentation was 35 degrees C, and the optimal pH range was 4 to 6. The fermentation of d-xylulose by yeast resulted in the production of ethanol as the major product; small amounts of xylitol and glycerol were also produced. The production of xylitol was influenced by pH as well as temperature. High pH values and low temperatures enhanced xylitol production. The rate of d-xylulose fermentation decreased when the production of ethanol yielded concentrations of 4% or more. The slow conversion rate of d-xylulose to ethanol was increased by increasing the yeast cell density. The overall production of ethanol from d-xylulose by yeast cells under optimal conditions was 90% of the theoretical yield.
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Affiliation(s)
- L C Chiang
- Laboratory of Renewable Resources Engineering, A. A. Potter Engineering Center, Purdue University, West Lafayette, Indiana 47907
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BYERS JAMESP, FOURNIER RONALDL, VARANASI SASIDHAR. A FEASIBILITY ANALYSIS OF A NOVEL APPROACH FOR THE CONVERSION OF XYLOSE TO ETHANOL. CHEM ENG COMMUN 2010. [DOI: 10.1080/00986449208935999] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- JAMES P. BYERS
- a Department of Chemical Engineering , The University of Toledo , Toledo, OH, 43606
| | - RONALD L. FOURNIER
- a Department of Chemical Engineering , The University of Toledo , Toledo, OH, 43606
| | - SASIDHAR VARANASI
- a Department of Chemical Engineering , The University of Toledo , Toledo, OH, 43606
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Beall DS, Ohta K, Ingram LO. Parametric studies of ethanol production form xylose and other sugars by recombinant Escherichia coli. Biotechnol Bioeng 2010; 38:296-303. [PMID: 18600763 DOI: 10.1002/bit.260380311] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The conversion of xylose to ethanol by recombinant Escherichia coli has been investigated in pH-controlled batch fermentations. Chemical and environmental parameters were varied to determine tolerance and to define optimal conditions. Relatively high concentrations of ethanol (56 g/L) were produced from xylose with excellent efficiencies. Volumetric productivities of up to 1.4 g ethanol/L h were obtained. Productivities, yields, and final ethanol concentrations achieved from xylose with recombinant E. coli exceeded the reported values with other organisms. In addition to xylose, all other sugar constituents of biomass (glucose, mannose, arabinose, and galactose) were efficiently converted to ethanol by recombinant E. coli. Unusually low inocula equivalent to 0.033 mg of dry cell weight/L were adequate for batch fermentations. The addition of small amounts of calcium, magnesium, and ferrous ions stimulated fermentation. The inhibitory effects of toxic compounds (salts, furfural, and acetate) which are present in hemicellulose hydrolysates were also examined.
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Affiliation(s)
- D S Beall
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida 32611, USA
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Zhang J, Heiss C, Thorne PG, Bal C, Azadi P, Lynd LR. Formation of ethyl β-xylopyranoside during simultaneous saccharification and co-fermentation of paper sludge. Enzyme Microb Technol 2009. [DOI: 10.1016/j.enzmictec.2008.10.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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40
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Keshwani DR, Cheng JJ. Switchgrass for bioethanol and other value-added applications: a review. BIORESOURCE TECHNOLOGY 2009; 100:1515-23. [PMID: 18976902 DOI: 10.1016/j.biortech.2008.09.035] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2008] [Revised: 09/11/2008] [Accepted: 09/11/2008] [Indexed: 05/02/2023]
Abstract
Switchgrass is a promising feedstock for value-added applications due to its high productivity, potentially low requirements for agricultural inputs and positive environmental impacts. The objective of this paper is to review published research on the conversion of switchgrass into bioethanol and other value-added products. Environmental benefits associated with switchgrass include the potential for carbon sequestration, nutrient recovery from runoff, soil remediation and provision of habitats for grassland birds. Pretreatment of switchgrass is required to improve the yields of fermentable sugars. Based on the type of pretreatment, glucose yields range from 70% to 90% and xylose yields range from 70% to 100% after hydrolysis. Following pretreatment and hydrolysis, ethanol yields range from 72% to 92% of the theoretical maximum. Other value-added uses of switchgrass include gasification, bio-oil production, newsprint production and fiber reinforcement in thermoplastic composites. Future prospects for research include increased biomass yields, optimization of feedstock composition for bioenergy applications, and efficient pentose fermentation to improve ethanol yields.
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Affiliation(s)
- Deepak R Keshwani
- Department of Biological and Agricultural Engineering, North Carolina State University, Raleigh, NC 27695-7625, USA
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42
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Schenberg AC, Pinto da Costa SO, Oliver SG. Molecular and Genetic Approaches to Alcohol Biotechnology in Brazil. Crit Rev Biotechnol 2008. [DOI: 10.3109/07388558709089386] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Stewart GG, Panchal CJ, Russell I, Sills AM. Biology of Ethanol-Producing Microorganisms. Crit Rev Biotechnol 2008. [DOI: 10.3109/07388558309077977] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Lovitt RW, Kim BH, Shen GJ, Zeikus JG, Phillips JA. Solvent Production by Microorganisms. Crit Rev Biotechnol 2008. [DOI: 10.3109/07388558809150725] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Enari TM, Suihko ML. Ethanol Production by Fermentation of Pentoses and Hexoses from Cellulosic Materials. Crit Rev Biotechnol 2008. [DOI: 10.3109/07388558309077980] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Rao RS, Bhadra B, Shivaji S. Isolation and characterization of ethanol-producing yeasts from fruits and tree barks. Lett Appl Microbiol 2008; 47:19-24. [PMID: 18498317 DOI: 10.1111/j.1472-765x.2008.02380.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS Isolation and identification of yeasts converting xylose to ethanol. METHODS AND RESULTS A total of 374 yeasts were isolated from a variety of rotten fruits and barks of trees. Out of these, 27 yeast strains were able to assimilate xylose and produce 0.12-0.38 g of ethanol per gram of xylose. Based on phylogenetic analysis of D1/D2 domain sequence of LSU (Large Subunit) rRNA gene and phenotypic characteristics the ethanol-producing strains were identified as member(s) of the genera Pichia, Candida, Kluyveromyces, Issatchenkia, Zygosacchraomyces, Clavispora, Debaryomyces, Metschnikowia, Rhodotorula and Cryptococcus. CONCLUSION Yeast strains producing ethanol from xylose have been isolated from a variety of rotten fruits and barks of trees and identified. SIGNIFICANCE AND IMPACT OF THE STUDY Environmental isolates of yeasts which could convert xylose to ethanol could form the basis for bio-fuel production and proper utilization of xylan rich agricultural and forest wastes.
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Affiliation(s)
- R S Rao
- Institution Centre for Cellular and Molecular Biology, Hyderabad, India
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Archer DB, Thompson LA. Energy production through the treatment of wastes by micro-organisms. ACTA ACUST UNITED AC 2008. [DOI: 10.1111/j.1365-2672.1987.tb03612.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Rao K, Chelikani S, Relue P, Varanasi S. A novel technique that enables efficient conduct of simultaneous isomerization and fermentation (SIF) of xylose. Appl Biochem Biotechnol 2008; 146:101-17. [PMID: 18421591 DOI: 10.1007/s12010-007-8122-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2007] [Accepted: 12/11/2007] [Indexed: 11/26/2022]
Abstract
Of the sugars recovered from lignocellulose, D-glucose can be readily converted into ethanol by baker's or brewer's yeast (Saccharomyces cerevisiae). However, xylose that is obtained by the hydrolysis of the hemicellulosic portion is not fermentable by the same species of yeasts. Xylose fermentation by native yeasts can be achieved via isomerization of xylose to its ketose isomer, xylulose. Isomerization with exogenous xylose isomerase (XI) occurs optimally at a pH of 7-8, whereas subsequent fermentation of xylulose to ethanol occurs at a pH of 4-5. We present a novel scheme for efficient isomerization of xylose to xylulose at conditions suitable for the fermentation by using an immobilized enzyme system capable of sustaining two different pH microenvironments in a single vessel. The proof-of-concept of the two-enzyme pellet is presented, showing conversion of xylose to xylulose even when the immobilized enzyme pellets are suspended in a bulk solution whose pH is sub-optimal for XI activity. The co-immobilized enzyme pellets may prove extremely valuable in effectively conducting "simultaneous isomerization and fermentation" (SIF) of xylose. To help further shift the equilibrium in favor of xylulose formation, sodium tetraborate (borax) was added to the isomerization solution. Binding of tetrahydroxyborate ions to xylulose effectively reduces the concentration of xylulose and leads to increased xylose isomerization. The formation of tetrahydroxyborate ions and the enhancement in xylulose production resulting from the complexation was studied at two different bulk pH values. The addition of 0.05 M borax to the isomerization solution containing our co-immobilized enzyme pellets resulted in xylose to xylulose conversion as high as 86% under pH conditions that are suboptimal for XI activity. These initial findings, which can be optimized for industrial conditions, have significant potential for increasing the yield of ethanol from xylose in an SIF approach.
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Affiliation(s)
- Kripa Rao
- Department of Chemical and Environmental Engineering, The University of Toledo, Toledo, OH 43606, USA
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Fermentation of d-glucose and d-xylose mixtures by Candida tropicalis NBRC 0618 for xylitol production. World J Microbiol Biotechnol 2007. [DOI: 10.1007/s11274-007-9527-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Govindaswamy S, Vane LM. Kinetics of growth and ethanol production on different carbon substrates using genetically engineered xylose-fermenting yeast. BIORESOURCE TECHNOLOGY 2007; 98:677-85. [PMID: 16563746 DOI: 10.1016/j.biortech.2006.02.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2004] [Revised: 01/05/2006] [Accepted: 02/01/2006] [Indexed: 05/08/2023]
Abstract
Saccharomyces cerevisiae 424A (LNH-ST) strain was used for fermentation of glucose and xylose. Growth kinetics and ethanol productivity were calculated for batch fermentation on media containing different combinations of glucose and xylose to give a final sugar concentration of 20+/-0.8 g/L. Growth rates obtained in pure xylose-based medium were less than those for media containing pure glucose and glucose-xylose mixtures. A maximum specific growth rate micro(max) of 0.291 h(-1) was obtained in YPD medium containing 20 g/L glucose as compared to 0.206 h(-1) in YPX medium containing 20 g/L xylose. In media containing combinations of glucose and xylose, glucose was exhausted first followed by xylose. Ethanol production on pure xylose entered log phase during the 12-24h period as compared to the 4-10h for pure glucose based medium using 2% inoculum. When glucose was added to fermentation flasks which had been initiated on a pure xylose-based medium, the rate of xylose usage was reduced indicating cosubstrate inhibition of xylose consumption by glucose.
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Affiliation(s)
- Shekar Govindaswamy
- National Risk Management Research Laboratory, US Environmental Protection Agency (MS 443), 26 W. Martin Luther King Dr., Cincinnati, OH 45268, USA
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