101
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Functional expression, production, and biochemical characterization of a laccase using yeast surface display technology. Fungal Biol 2016; 120:1609-1622. [PMID: 27890094 DOI: 10.1016/j.funbio.2016.08.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 08/15/2016] [Accepted: 08/19/2016] [Indexed: 01/12/2023]
Abstract
A Trametes versicolor laccase was functionally expressed on the membrane surface of Saccharomyces cerevisiae EBY100. Laccase expression was increased 6.57-fold by medium optimization and surpassed production by the native strain. Maximal laccase and biomass production reached 19 735 ± 1719 Ug-1 and 6.22 ± 0.53 gL-1 respectively, after 2 d of culture. Optimum oxidization of all substrates by laccase was observed at pH 3. Laccase showed high affinity towards substrates used with Km (mM) and Vmax (μmol min-1) values of 0.57 ± 0.0047 and 24.55 ± 0.64, 1.52 ± 0.52 and 9.25 ± 1.78, and 2.67 ± 0.12 and 11.26 ± 0.75, were reported for ABTS, 2, 6-DMP and GUA, respectively. EDTA and NaN3 displayed none competitive inhibition towards laccase activity. The optimum temperature for activity was 50 °C; however, the enzyme was stable over a wide range of temperatures (25-70 °C). The biologically immobilized laccase showed high reusability towards phenolic substrates and low reusability with non-phenolic substrates. High affinity for a diversity phenolic compounds and great ethanol tolerance substantiates this laccase/yeast biocatalyst potential for application in the production of bioethanol.
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102
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Zhao X, Xiong L, Zhang M, Bai F. Towards efficient bioethanol production from agricultural and forestry residues: Exploration of unique natural microorganisms in combination with advanced strain engineering. BIORESOURCE TECHNOLOGY 2016; 215:84-91. [PMID: 27067672 DOI: 10.1016/j.biortech.2016.03.158] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 03/29/2016] [Accepted: 03/30/2016] [Indexed: 05/14/2023]
Abstract
Production of fuel ethanol from lignocellulosic feedstocks such as agricultural and forestry residues is receiving increasing attention due to the unsustainable supply of fossil fuels. Three key challenges include high cellulase production cost, toxicity of the cellulosic hydrolysate to microbial strains, and poor ability of fermenting microorganisms to utilize certain fermentable sugars in the hydrolysate. In this article, studies on searching of natural microbial strains for production of unique cellulase for biorefinery of agricultural and forestry wastes, as well as development of strains for improved cellulase production were reviewed. In addition, progress in the construction of yeast strains with improved stress tolerance and the capability to fully utilize xylose and glucose in the cellulosic hydrolysate was also summarized. With the superior microbial strains for high titer cellulase production and efficient utilization of all fermentable sugars in the hydrolysate, economic biofuels production from agricultural residues and forestry wastes can be realized.
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Affiliation(s)
- Xinqing Zhao
- State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Liang Xiong
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China
| | - Mingming Zhang
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China
| | - Fengwu Bai
- State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China
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103
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Venkateswar Rao L, Goli JK, Gentela J, Koti S. Bioconversion of lignocellulosic biomass to xylitol: An overview. BIORESOURCE TECHNOLOGY 2016; 213:299-310. [PMID: 27142629 DOI: 10.1016/j.biortech.2016.04.092] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 04/16/2016] [Accepted: 04/19/2016] [Indexed: 06/05/2023]
Abstract
Lignocellulosic wastes include agricultural and forest residues which are most promising alternative energy sources and serve as potential low cost raw materials that can be exploited to produce xylitol. The strong physical and chemical construction of lignocelluloses is a major constraint for the recovery of xylose. The large scale production of xylitol is attained by nickel catalyzed chemical process that is based on xylose hydrogenation, that requires purified xylose as raw substrate and the process requires high temperature and pressure that remains to be cost intensive and energy consuming. Therefore, there is a necessity to develop an integrated process for biotechnological conversion of lignocelluloses to xylitol and make the process economical. The present review confers about the pretreatment strategies that facilitate cellulose and hemicellulose acquiescent for hydrolysis. There is also an emphasis on various detoxification and fermentation methodologies including genetic engineering strategies for the efficient conversion of xylose to xylitol.
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Affiliation(s)
- Linga Venkateswar Rao
- Dept. of Microbiology, Osmania University, Hyderabad, Telangana State 500 007, India.
| | - Jyosthna Khanna Goli
- Dept. of Microbiology, Osmania University, Hyderabad, Telangana State 500 007, India
| | - Jahnavi Gentela
- Dept. of Microbiology, Osmania University, Hyderabad, Telangana State 500 007, India
| | - Sravanthi Koti
- Dept. of Microbiology, Osmania University, Hyderabad, Telangana State 500 007, India
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104
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Optimization and modeling of diananofiltration process for the detoxification of ligno-cellulosic hydrolysates - Study at pre-industrial scale. J Memb Sci 2016. [DOI: 10.1016/j.memsci.2016.04.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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105
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Rajaraman E, Agarwal A, Crigler J, Seipelt-Thiemann R, Altman E, Eiteman MA. Transcriptional analysis and adaptive evolution of Escherichia coli strains growing on acetate. Appl Microbiol Biotechnol 2016; 100:7777-85. [DOI: 10.1007/s00253-016-7724-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 06/25/2016] [Accepted: 07/02/2016] [Indexed: 10/21/2022]
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106
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Coz A, Llano T, Cifrián E, Viguri J, Maican E, Sixta H. Physico-Chemical Alternatives in Lignocellulosic Materials in Relation to the Kind of Component for Fermenting Purposes. MATERIALS 2016; 9:ma9070574. [PMID: 28773700 PMCID: PMC5456911 DOI: 10.3390/ma9070574] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 07/04/2016] [Accepted: 07/08/2016] [Indexed: 11/16/2022]
Abstract
The complete bioconversion of the carbohydrate fraction is of great importance for a lignocellulosic-based biorefinery. However, due to the structure of the lignocellulosic materials, and depending basically on the main parameters within the pretreatment steps, numerous byproducts are generated and they act as inhibitors in the fermentation operations. In this sense, the impact of inhibitory compounds derived from lignocellulosic materials is one of the major challenges for a sustainable biomass-to-biofuel and -bioproduct industry. In order to minimise the negative effects of these compounds, numerous methodologies have been tested including physical, chemical, and biological processes. The main physical and chemical treatments have been studied in this work in relation to the lignocellulosic material and the inhibitor in order to point out the best mechanisms for fermenting purposes. In addition, special attention has been made in the case of lignocellulosic hydrolysates obtained by chemical processes with SO₂, due to the complex matrix of these materials and the increase in these methodologies in future biorefinery markets. Recommendations of different detoxification methods have been given.
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Affiliation(s)
- Alberto Coz
- Green Engineering and Resources, Department of Chemistry and Process and Resource Engineering, University of Cantabria, Avda. Los Castros s/n, Santander 39005, Spain.
| | - Tamara Llano
- Green Engineering and Resources, Department of Chemistry and Process and Resource Engineering, University of Cantabria, Avda. Los Castros s/n, Santander 39005, Spain.
| | - Eva Cifrián
- Green Engineering and Resources, Department of Chemistry and Process and Resource Engineering, University of Cantabria, Avda. Los Castros s/n, Santander 39005, Spain.
| | - Javier Viguri
- Green Engineering and Resources, Department of Chemistry and Process and Resource Engineering, University of Cantabria, Avda. Los Castros s/n, Santander 39005, Spain.
| | - Edmond Maican
- Faculty of Biotechnical Systems Engineering, Politehnica University of Bucharest, 313 Splaiul Independentei, Sector 6, Bucuresti 060042, Romania.
| | - Herbert Sixta
- Department of Forest Products Technology, School of Chemistry, Aalto University, P.O. Box 16300, Aalto FI-00076, Finland.
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107
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Applying functional metagenomics to search for novel lignocellulosic enzymes in a microbial consortium derived from a thermophilic composting phase of sugarcane bagasse and cow manure. Antonie van Leeuwenhoek 2016; 109:1217-33. [DOI: 10.1007/s10482-016-0723-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 06/07/2016] [Indexed: 10/21/2022]
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108
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A Bacterial Laccase for Enhancing Saccharification and Ethanol Fermentation of Steam-Pretreated Biomass. FERMENTATION-BASEL 2016. [DOI: 10.3390/fermentation2020011] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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109
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Papapetridis I, van Dijk M, Dobbe APA, Metz B, Pronk JT, van Maris AJA. Improving ethanol yield in acetate-reducing Saccharomyces cerevisiae by cofactor engineering of 6-phosphogluconate dehydrogenase and deletion of ALD6. Microb Cell Fact 2016; 15:67. [PMID: 27118055 PMCID: PMC5574463 DOI: 10.1186/s12934-016-0465-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 04/13/2016] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Acetic acid, an inhibitor of sugar fermentation by yeast, is invariably present in lignocellulosic hydrolysates which are used or considered as feedstocks for yeast-based bioethanol production. Saccharomyces cerevisiae strains have been constructed, in which anaerobic reduction of acetic acid to ethanol replaces glycerol formation as a mechanism for reoxidizing NADH formed in biosynthesis. An increase in the amount of acetate that can be reduced to ethanol should further decrease acetic acid concentrations and enable higher ethanol yields in industrial processes based on lignocellulosic feedstocks. The stoichiometric requirement of acetate reduction for NADH implies that increased generation of NADH in cytosolic biosynthetic reactions should enhance acetate consumption. RESULTS Replacement of the native NADP(+)-dependent 6-phosphogluconate dehydrogenase in S. cerevisiae by a prokaryotic NAD(+)-dependent enzyme resulted in increased cytosolic NADH formation, as demonstrated by a ca. 15% increase in the glycerol yield on glucose in anaerobic cultures. Additional deletion of ALD6, which encodes an NADP(+)-dependent acetaldehyde dehydrogenase, led to a 39% increase in the glycerol yield compared to a non-engineered strain. Subsequent replacement of glycerol formation by an acetate reduction pathway resulted in a 44% increase of acetate consumption per amount of biomass formed, as compared to an engineered, acetate-reducing strain that expressed the native 6-phosphogluconate dehydrogenase and ALD6. Compared to a non-acetate reducing reference strain under the same conditions, this resulted in a ca. 13% increase in the ethanol yield on glucose. CONCLUSIONS The combination of NAD(+)-dependent 6-phosphogluconate dehydrogenase expression and deletion of ALD6 resulted in a marked increase in the amount of acetate that was consumed in these proof-of-principle experiments, and this concept is ready for further testing in industrial strains as well as in hydrolysates. Altering the cofactor specificity of the oxidative branch of the pentose-phosphate pathway in S. cerevisiae can also be used to increase glycerol production in wine fermentation and to improve NADH generation and/or generation of precursors derived from the pentose-phosphate pathway in other industrial applications of this yeast.
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Affiliation(s)
- Ioannis Papapetridis
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
| | - Marlous van Dijk
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
| | - Arthur PA Dobbe
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
| | - Benjamin Metz
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
| | - Jack T. Pronk
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
| | - Antonius J. A. van Maris
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
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110
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Wang X, Zhuang J, Fu Y, Tian G, Wang Z, Qin M. Separation of hemicellulose-derived saccharides from wood hydrolysate by lime and ion exchange resin. BIORESOURCE TECHNOLOGY 2016; 206:225-230. [PMID: 26859331 DOI: 10.1016/j.biortech.2016.01.107] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 01/27/2016] [Accepted: 01/28/2016] [Indexed: 06/05/2023]
Abstract
A combined process of lime treatment and mixed bed ion exchange was proposed to separate hemicellulose-derived saccharides (HDS) from prehydrolysis liquor (PHL) of lignocellulose as value added products. The optimization of lime treatment achieved up to 44.2% removal of non-saccharide organic compounds (NSOC), mainly colloidal substances, with negligible HDS degradation at 0.5% lime level and subsequent neutralization by phosphoric acid. The residual NSOC and calcium ions in lime-treated PHL were eliminated by mixed bed ion exchange. The breakthrough curves of HDS and NSOC showed selective retention toward NSOC, leading to 75% HDS recovery with 95% purity at 17 bed volumes of exchange capacity. In addition, macroporous resin showed higher exchange capacity than gel resin as indicated by the triple processing volume. The remarkable selectivity of the combined process suggested the feasibility for HDS separation from PHL.
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Affiliation(s)
- Xiaojun Wang
- Key Laboratory of Paper Science & Technology, Qilu University of Technology, Jinan 250353, China
| | - Jingshun Zhuang
- Key Laboratory of Paper Science & Technology, Qilu University of Technology, Jinan 250353, China
| | - Yingjuan Fu
- Key Laboratory of Paper Science & Technology, Qilu University of Technology, Jinan 250353, China
| | - Guoyu Tian
- Key Laboratory of Paper Science & Technology, Qilu University of Technology, Jinan 250353, China
| | - Zhaojiang Wang
- Key Laboratory of Paper Science & Technology, Qilu University of Technology, Jinan 250353, China.
| | - Menghua Qin
- Laboratory of Organic Chemistry, Taishan University, Taian 271021, China
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111
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Jayakody LN, Ferdouse J, Hayashi N, Kitagaki H. Identification and detoxification of glycolaldehyde, an unattended bioethanol fermentation inhibitor. Crit Rev Biotechnol 2016; 37:177-189. [PMID: 26953525 DOI: 10.3109/07388551.2015.1128877] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Although there have been approximately 60 chemical compounds identified as potent fermentation inhibitors in lignocellulose hydrolysate, our research group recently discovered glycolaldehyde as a key fermentation inhibitor during second generation biofuel production. Accordingly, we have developed a yeast S. cerevisiae strain exhibiting tolerance to glycolaldehyde. During this glycolaldehyde study, we established novel approaches for rational engineering of inhibitor-tolerant S. cerevisiae strains, including engineering redox cofactors and engineering the SUMOylation pathway. These new technical dimensions provide a novel platform for engineering S. cerevisiae strains to overcome one of the key barriers for industrialization of lignocellulosic ethanol production. As such, this review discusses novel biochemical insight of glycolaldehyde in the context of the biofuel industry.
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Affiliation(s)
- Lahiru N Jayakody
- a Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign , Urbana , IL , USA.,b Department of Biochemistry and Applied Biosciences United Graduate School of Agricultural Sciences , Kagoshima University , Kagoshima , Japan , and
| | - Jannatul Ferdouse
- c Department of Environmental Sciences Faculty of Agriculture , Saga University , Saga , Japan
| | - Nobuyuki Hayashi
- c Department of Environmental Sciences Faculty of Agriculture , Saga University , Saga , Japan
| | - Hiroshi Kitagaki
- b Department of Biochemistry and Applied Biosciences United Graduate School of Agricultural Sciences , Kagoshima University , Kagoshima , Japan , and.,c Department of Environmental Sciences Faculty of Agriculture , Saga University , Saga , Japan
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112
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Zhang L, Li X, Yong Q, Yang ST, Ouyang J, Yu S. Impacts of lignocellulose-derived inhibitors on L-lactic acid fermentation by Rhizopus oryzae. BIORESOURCE TECHNOLOGY 2016; 203:173-80. [PMID: 26724548 DOI: 10.1016/j.biortech.2015.12.014] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 11/28/2015] [Accepted: 12/08/2015] [Indexed: 05/23/2023]
Abstract
Inhibitors generated in the pretreatment and hydrolysis of corn stover and corn cob were identified. In general, they inhibited cell growth, lactate dehydrogenase, and lactic acid production but with less or no adverse effect on alcohol dehydrogenase and ethanol production in batch fermentation by Rhizopus oryzae. Furfural and 5-hydroxymethyl furfural (HMF) were highly toxic at 0.5-1 g L(-1), while formic and acetic acids at less than 4 g L(-1) and levulinic acid at 10 g L(-1) were not toxic. Among the phenolic compounds at 1 g L(-1), trans-cinnamic acid and syringaldehyde had the highest toxicity while syringic, ferulic and p-coumaric acids were not toxic. Although these inhibitors were present at concentrations much lower than their separately identified toxic levels, lactic acid fermentation with the hydrolysates showed much inferior performance compared to the control without inhibitor, suggesting synergistic or compounded effects of the lignocellulose-degraded compounds on inhibiting lactic acid fermentation.
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Affiliation(s)
- Li Zhang
- College of Chemical Engineering, Nanjing Forestry University, 159 Longpan Road, Nanjing 210037, PR China; William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 151 West Woodruff Avenue, Columbus, OH 43210, USA
| | - Xin Li
- College of Chemical Engineering, Nanjing Forestry University, 159 Longpan Road, Nanjing 210037, PR China
| | - Qiang Yong
- College of Chemical Engineering, Nanjing Forestry University, 159 Longpan Road, Nanjing 210037, PR China
| | - Shang-Tian Yang
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 151 West Woodruff Avenue, Columbus, OH 43210, USA.
| | - Jia Ouyang
- College of Chemical Engineering, Nanjing Forestry University, 159 Longpan Road, Nanjing 210037, PR China
| | - Shiyuan Yu
- College of Chemical Engineering, Nanjing Forestry University, 159 Longpan Road, Nanjing 210037, PR China
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113
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Jiang T, Qiao H, Zheng Z, Chu Q, Li X, Yong Q, Ouyang J. Lactic Acid Production from Pretreated Hydrolysates of Corn Stover by a Newly Developed Bacillus coagulans Strain. PLoS One 2016; 11:e0149101. [PMID: 26863012 PMCID: PMC4749344 DOI: 10.1371/journal.pone.0149101] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 01/27/2016] [Indexed: 01/20/2023] Open
Abstract
An inhibitor-tolerance strain, Bacillus coagulans GKN316, was developed through atmospheric and room temperature plasma (ARTP) mutation and evolution experiment in condensed dilute-acid hydrolysate (CDH) of corn stover. The fermentabilities of other hydrolysates with B. coagulans GKN316 and the parental strain B. coagulans NL01 were assessed. When using condensed acid-catalyzed steam-exploded hydrolysate (CASEH), condensed acid-catalyzed liquid hot water hydrolysate (CALH) and condensed acid-catalyzed sulfite hydrolysate (CASH) as substrates, the concentration of lactic acid reached 45.39, 16.83, and 18.71 g/L by B. coagulans GKN316, respectively. But for B. coagulans NL01, only CASEH could be directly fermented to produce 15.47 g/L lactic acid. The individual inhibitory effect of furfural, 5-hydroxymethylfurfural (HMF), vanillin, syringaldehyde and p-hydroxybenzaldehyde (pHBal) on xylose utilization by B. coagulans GKN316 was also studied. The strain B. coagulans GKN316 could effectively convert these toxic inhibitors to the less toxic corresponding alcohols in situ. These results suggested that B. coagulans GKN316 was well suited to production of lactic acid from undetoxified lignocellulosic hydrolysates.
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Affiliation(s)
- Ting Jiang
- College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, People’s Republic of China
| | - Hui Qiao
- College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, People’s Republic of China
| | - Zhaojuan Zheng
- College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, People’s Republic of China
| | - Qiulu Chu
- College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, People’s Republic of China
| | - Xin Li
- College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, People’s Republic of China
| | - Qiang Yong
- Key Laboratory of Forest Genetics and Biotechnology of the Ministry of Education, Nanjing Forestry University, Nanjing, 210037, People’s Republic of China
| | - Jia Ouyang
- College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, People’s Republic of China
- Key Laboratory of Forest Genetics and Biotechnology of the Ministry of Education, Nanjing Forestry University, Nanjing, 210037, People’s Republic of China
- * E-mail:
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114
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Tan HT, Corbin KR, Fincher GB. Emerging Technologies for the Production of Renewable Liquid Transport Fuels from Biomass Sources Enriched in Plant Cell Walls. FRONTIERS IN PLANT SCIENCE 2016; 7:1854. [PMID: 28018390 PMCID: PMC5161040 DOI: 10.3389/fpls.2016.01854] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 11/24/2016] [Indexed: 05/15/2023]
Abstract
Plant cell walls are composed predominantly of cellulose, a range of non-cellulosic polysaccharides and lignin. The walls account for a large proportion not only of crop residues such as wheat straw and sugarcane bagasse, but also of residues of the timber industry and specialist grasses and other plants being grown specifically for biofuel production. The polysaccharide components of plant cell walls have long been recognized as an extraordinarily large source of fermentable sugars that might be used for the production of bioethanol and other renewable liquid transport fuels. Estimates place annual plant cellulose production from captured light energy in the order of hundreds of billions of tons. Lignin is synthesized in the same order of magnitude and, as a very large polymer of phenylpropanoid residues, lignin is also an abundant, high energy macromolecule. However, one of the major functions of these cell wall constituents in plants is to provide the extreme tensile and compressive strengths that enable plants to resist the forces of gravity and a broad range of other mechanical forces. Over millions of years these wall constituents have evolved under natural selection to generate extremely tough and resilient biomaterials. The rapid degradation of these tough cell wall composites to fermentable sugars is therefore a difficult task and has significantly slowed the development of a viable lignocellulose-based biofuels industry. However, good progress has been made in overcoming this so-called recalcitrance of lignocellulosic feedstocks for the biofuels industry, through modifications to the lignocellulose itself, innovative pre-treatments of the biomass, improved enzymes and the development of superior yeasts and other microorganisms for the fermentation process. Nevertheless, it has been argued that bioethanol might not be the best or only biofuel that can be generated from lignocellulosic biomass sources and that hydrocarbons with intrinsically higher energy densities might be produced using emerging and continuous flow systems that are capable of converting a broad range of plant and other biomasses to bio-oils through so-called 'agnostic' technologies such as hydrothermal liquefaction. Continued attention to regulatory frameworks and ongoing government support will be required for the next phase of development of internationally viable biofuels industries.
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Affiliation(s)
- Hwei-Ting Tan
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, BrisbaneQLD, Australia
| | - Kendall R. Corbin
- Centre for Marine Bioproducts Development, School of Medicine, Flinders University, Bedford ParkSA, Australia
| | - Geoffrey B. Fincher
- Australian Research Council Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, University of Adelaide, Glen OsmondSA, Australia
- *Correspondence: Geoffrey B. Fincher,
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115
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Zhang K, Pei Z, Wang D. Organic solvent pretreatment of lignocellulosic biomass for biofuels and biochemicals: A review. BIORESOURCE TECHNOLOGY 2016; 199:21-33. [PMID: 26343573 DOI: 10.1016/j.biortech.2015.08.102] [Citation(s) in RCA: 260] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 08/21/2015] [Accepted: 08/22/2015] [Indexed: 05/28/2023]
Abstract
Lignocellulosic biomass represents the largest potential volume and lowest cost for biofuel and biochemical production. Pretreatment is an essential component of biomass conversion process, affecting a majority of downstream processes, including enzymatic hydrolysis, fermentation, and final product separation. Organic solvent pretreatment is recognized as an emerging way ahead because of its inherent advantages, such as the ability to fractionate lignocellulosic biomass into cellulose, lignin, and hemicellulose components with high purity, as well as easy solvent recovery and solvent reuse. Objectives of this review were to update and extend previous works on pretreatment of lignocellulosic biomass for biofuels and biochemicals using organic solvents, especially on ethanol, methanol, ethylene glycol, glycerol, acetic acid, and formic acid. Perspectives and recommendations were given to fully describe implementation of proper organic solvent pretreatment for future research.
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Affiliation(s)
- Ke Zhang
- Department of Biological and Agricultural Engineering, Kansas State University, Manhattan, KS 66506, USA
| | - Zhijian Pei
- Department of Industrial and Manufacturing Systems Engineering, Kansas State University, Manhattan, KS 66506, USA
| | - Donghai Wang
- Department of Biological and Agricultural Engineering, Kansas State University, Manhattan, KS 66506, USA
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116
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117
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Favaro L, Corte L, Roscini L, Cagnin L, Tiecco M, Colabella C, Berti A, Basaglia M, Cardinali G, Casella S. A novel FTIR-based approach to evaluate the interactions between lignocellulosic inhibitory compounds and their effect on yeast metabolism. RSC Adv 2016. [DOI: 10.1039/c6ra08859g] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
FTIR analysis revealed antagonistic effects between lignocellulosic inhibitory compounds through the metabolomic alterations induced on differentS. cerevisiaestrains.
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Affiliation(s)
- Lorenzo Favaro
- Department of Agronomy Food Natural Resources Animals and Environment (DAFNAE)
- University of Padova
- Italy
| | - Laura Corte
- Department of Pharmaceutical Sciences-Microbiology
- University of Perugia
- I-06121 Perugia
- Italy
| | - Luca Roscini
- Department of Pharmaceutical Sciences-Microbiology
- University of Perugia
- I-06121 Perugia
- Italy
| | - Lorenzo Cagnin
- Department of Agronomy Food Natural Resources Animals and Environment (DAFNAE)
- University of Padova
- Italy
| | - Matteo Tiecco
- CEMIN, Centre of Excellence on Nanostructured Innovative Materials
- Department of Chemistry, Biology and Biotechnology
- University of Perugia
- Italy
| | - Claudia Colabella
- Department of Pharmaceutical Sciences-Microbiology
- University of Perugia
- I-06121 Perugia
- Italy
| | - Antonio Berti
- Department of Agronomy Food Natural Resources Animals and Environment (DAFNAE)
- University of Padova
- Italy
| | - Marina Basaglia
- Department of Agronomy Food Natural Resources Animals and Environment (DAFNAE)
- University of Padova
- Italy
| | - Gianluigi Cardinali
- Department of Pharmaceutical Sciences-Microbiology
- University of Perugia
- I-06121 Perugia
- Italy
- CEMIN, Centre of Excellence on Nanostructured Innovative Materials
| | - Sergio Casella
- Department of Agronomy Food Natural Resources Animals and Environment (DAFNAE)
- University of Padova
- Italy
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118
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He Y, Zhang J, Bao J. Acceleration of biodetoxification on dilute acid pretreated lignocellulose feedstock by aeration and the consequent ethanol fermentation evaluation. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:19. [PMID: 26816529 PMCID: PMC4727304 DOI: 10.1186/s13068-016-0438-9] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2015] [Accepted: 01/08/2016] [Indexed: 05/15/2023]
Abstract
BACKGROUND Biodetoxification by the fungus Amorphotheca resinae ZN1 provides an effective way of inhibitor removal from pretreated lignocellulose feedstock and has been applied in the process of ethanol, biolipids, and lactic acid production. However, the long-time used and the consumption of considerable xylose in the pretreated materials reduced the process efficiency. The improvements of biodetoxification should be made to enhance the production of biochemical from lignocellulosic materials. RESULTS This study reported an acceleration method of A. resinae ZN1-based biodetoxification on the corn stover (CS) feedstock pretreated using dry dilute acid pretreatment. Under proper aeration and well-mixing condition, the conversion rate of furfural, 5-hydroxymethylfurfural (HMF), acetic acid, and typical phenolic compounds were significantly accelerated by more than twofolds faster, which resulted in the reduction of biodetoxification time from 96 h in the conventional process to 36 h. Simultaneous saccharification and ethanol fermentation assay on accelerated biodetoxification of the dry dilute acid pretreated CS feedstock achieved the similar ethanol titer (48.56 g/L of 36 h' accelerated biodetoxification vs. 50.00 g/L of 4 days' conventional biodetoxification) and yield (58.10 vs. 59.63 %). Substrate priority of inhibitors to sugars by A. resinae ZN1 was discovered and considerable xylose was reserved in the accelerated biodetoxification. Cell growth of A. resinae fungus in liquid medium and on pretreated CS solids revealed that the enhanced aeration enhanced the biodetoxification rate rather than the cell growth rate. Accelerated inhibitor conversion might come from the increased supply of cofactors of nicotinamide adenine dinucleotide or nicotinamide adenine dinucleotide phosphate from the step of aldehyde inhibitors to the corresponding acids, instead of cell mass increase. CONCLUSION Accelerated biodetoxification reduced the period of biodetoxification and retained the xylose components in the pretreated CS, which provided a practical method on improving process efficiency for cellulosic ethanol production from severe pretreated lignocellulose feedstock.
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Affiliation(s)
- Yanqing He
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, 200237 Shanghai, China
| | - Jian Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, 200237 Shanghai, China
| | - Jie Bao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, 200237 Shanghai, China
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119
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13C-Metabolic Flux Analysis: An Accurate Approach to Demystify Microbial Metabolism for Biochemical Production. Bioengineering (Basel) 2015; 3:bioengineering3010003. [PMID: 28952565 PMCID: PMC5597161 DOI: 10.3390/bioengineering3010003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 12/10/2015] [Accepted: 12/18/2015] [Indexed: 12/15/2022] Open
Abstract
Metabolic engineering of various industrial microorganisms to produce chemicals, fuels, and drugs has raised interest since it is environmentally friendly, sustainable, and independent of nonrenewable resources. However, microbial metabolism is so complex that only a few metabolic engineering efforts have been able to achieve a satisfactory yield, titer or productivity of the target chemicals for industrial commercialization. In order to overcome this challenge, 13C Metabolic Flux Analysis (13C-MFA) has been continuously developed and widely applied to rigorously investigate cell metabolism and quantify the carbon flux distribution in central metabolic pathways. In the past decade, many 13C-MFA studies have been performed in academic labs and biotechnology industries to pinpoint key issues related to microbe-based chemical production. Insightful information about the metabolic rewiring has been provided to guide the development of the appropriate metabolic engineering strategies for improving the biochemical production. In this review, we will introduce the basics of 13C-MFA and illustrate how 13C-MFA has been applied via integration with metabolic engineering to identify and tackle the rate-limiting steps in biochemical production for various host microorganisms
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120
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Zhang Y, Li M, Wang Y, Ji X, Zhang L, Hou L. Simultaneous concentration and detoxification of lignocellulosic hydrolyzates by vacuum membrane distillation coupled with adsorption. BIORESOURCE TECHNOLOGY 2015; 197:276-283. [PMID: 26342339 DOI: 10.1016/j.biortech.2015.08.097] [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: 06/21/2015] [Revised: 08/17/2015] [Accepted: 08/18/2015] [Indexed: 06/05/2023]
Abstract
Low sugar concentration and the presence of various inhibitors are the major challenges associated with lignocellulosic hydrolyzates as a fermentation broth. Vacuum membrane distillation (VMD) process can be used to concentrate sugars and remove inhibitors (furans) efficiently, but it's not desirable for the removal of less volatile inhibitors such as acetic acid. In this study, a VMD-adsorption process was proposed to improve the removal of acetic acid, achieving simultaneous concentration and detoxification of lignocellulosic hydrolyzates by one step process. Results showed that sugars were concentrated with high rejections (>98%) and little sugar loss (<2%), with the significant reduction in nearly total furans (99.7%) and acetic acid (83.5%) under optimal operation conditions. Fermentation results showed the ethanol production of hydrolyzates concentrated and detoxified using the VMD-adsorption method were approximately 10-fold greater than from untreated hydrolyzates.
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Affiliation(s)
- Yaqin Zhang
- Key Laboratory of Biomass Chemical Engineering of MOE, Department of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
| | - Ming Li
- Xi'an High-Tech Institute, Xi'an 710025, China
| | - Yafei Wang
- Key Laboratory of Biomass Chemical Engineering of MOE, Department of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
| | - Xiaosheng Ji
- Ocean College, Zhejiang University, Hangzhou 310058, China
| | - Lin Zhang
- Key Laboratory of Biomass Chemical Engineering of MOE, Department of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China.
| | - Lian Hou
- Key Laboratory of Biomass Chemical Engineering of MOE, Department of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China; Xi'an High-Tech Institute, Xi'an 710025, China
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121
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Lin R, Cheng J, Ding L, Song W, Zhou J, Cen K. Sodium borohydride removes aldehyde inhibitors for enhancing biohydrogen fermentation. BIORESOURCE TECHNOLOGY 2015; 197:323-328. [PMID: 26342346 DOI: 10.1016/j.biortech.2015.08.105] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 08/25/2015] [Accepted: 08/26/2015] [Indexed: 06/05/2023]
Abstract
To enhance biohydrogen production from glucose and xylose in the presence of aldehyde inhibitors, reducing agent (i.e., sodium borohydride) was in situ added for effective detoxification. The detoxification efficiencies of furfural (96.7%) and 5-hydroxymethylfurfural (5-HMF, 91.7%) with 30mM NaBH4 were much higher than those of vanillin (77.3%) and syringaldehyde (69.3%). Biohydrogen fermentation was completely inhibited without detoxification, probably because of the consumption of nicotinamide adenine dinucleotide (NADH) by inhibitors reduction (R-CHO+2NADH→R-CH2OH+2NAD(+)). Addition of 30mM NaBH4 provided the reducing power necessary for inhibitors reduction (4R-CHO+NaBH4+2H2O→4R-CH2OH+NaBO2). The recovered reducing power in fermentation resulted in 99.3% recovery of the hydrogen yield and 64.6% recovery of peak production rate. Metabolite production and carbon conversion after detoxification significantly increased to 63.7mM and 81.9%, respectively.
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Affiliation(s)
- Richen Lin
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China
| | - Jun Cheng
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China.
| | - Lingkan Ding
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China
| | - Wenlu Song
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China; Department of Life Science and Engineering, Jining University, Jining 273155, China
| | - Junhu Zhou
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China
| | - Kefa Cen
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China
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122
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Shen Y, Jarboe L, Brown R, Wen Z. A thermochemical–biochemical hybrid processing of lignocellulosic biomass for producing fuels and chemicals. Biotechnol Adv 2015; 33:1799-813. [DOI: 10.1016/j.biotechadv.2015.10.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 10/16/2015] [Accepted: 10/16/2015] [Indexed: 12/28/2022]
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123
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Lee SJ, Lee JH, Yang X, Kim SB, Lee JH, Yoo HY, Park C, Kim SW. Phenolic compounds: Strong inhibitors derived from lignocellulosic hydrolysate for 2,3-butanediol production by Enterobacter aerogenes. Biotechnol J 2015; 10:1920-8. [PMID: 26479290 DOI: 10.1002/biot.201500090] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Revised: 07/22/2015] [Accepted: 10/14/2015] [Indexed: 11/07/2022]
Abstract
Lignocellulosic biomass are attractive feedstocks for 2,3-butanediol production due to their abundant supply and low price. During the hydrolysis of lignocellulosic biomass, various byproducts are formed and their effects on 2,3-butanediol production were not sufficiently studied compared to ethanol production. Therefore, the effects of compounds derived from lignocellulosic biomass (weak acids, furan derivatives and phenolics) on the cell growth, the 2,3-butanediol production and the enzymes activity involved in 2,3-butanediol production were evaluated using Enterobacter aerogenes ATCC 29007. The phenolic compounds showed the most toxic effects on cell growth, 2,3-butanediol production and enzyme activity, followed by furan derivatives and weak acids. The significant effects were not observed in the presence of acetic acid and formic acid. Also, feasibility of 2,3-butanediol production from lignocellulosic biomass was evaluated using Miscanthus as a feedstock. In the fermentation of Miscanthus hydrolysate, 11.00 g/L of 2,3-butanediol was obtained from 34.62 g/L of reducing sugar. However, 2,3-butanediol was not produced when the concentration of total phenolic compounds in the hydrolysate increased to more than 1.5 g/L. The present study provides useful information to develop strategies for biological production of 2,3-butanediol and to establish biorefinery for biochemicals from lignocellulosic biomass.
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Affiliation(s)
- Sang Jun Lee
- Department of Chemical and Biological Engineering, Korea University, Seoul, Republic of Korea
| | - Ju Hun Lee
- Department of Chemical and Biological Engineering, Korea University, Seoul, Republic of Korea
| | - Xiaoguang Yang
- Department of Chemical and Biological Engineering, Korea University, Seoul, Republic of Korea
| | - Sung Bong Kim
- Department of Chemical and Biological Engineering, Korea University, Seoul, Republic of Korea
| | - Ja Hyun Lee
- Department of Chemical and Biological Engineering, Korea University, Seoul, Republic of Korea
| | - Hah Young Yoo
- Department of Chemical and Biological Engineering, Korea University, Seoul, Republic of Korea
| | - Chulhwan Park
- Department of Chemical Engineering, Kwangwoon University, Seoul, Republic of Korea.
| | - Seung Wook Kim
- Department of Chemical and Biological Engineering, Korea University, Seoul, Republic of Korea.
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124
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Kurosawa K, Anthony Debono C, Sinskey AJ. Lignocellulose-derived inhibitors improve lipid extraction from wet Rhodococcus opacus cells. BIORESOURCE TECHNOLOGY 2015; 193:206-212. [PMID: 26141279 DOI: 10.1016/j.biortech.2015.05.103] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 05/27/2015] [Accepted: 05/28/2015] [Indexed: 06/04/2023]
Abstract
Extracting lipids from oleaginous microbial cells in a cost effective and environmentally compatible manner remains a critical challenge in developing manufacturing paradigms for advanced liquid biofuels. In this study, a new approach using microbial growth inhibitors from lignocellulose-derived feedstocks was used to extract lipids efficiently from wet cell mass of the oleaginous bacterium Rhodococcus opacus MITXM-61. Nine common lignocellulose-derived inhibitors for treatment of cells prior to solvent extraction were used and evaluated for their efficiency of lipid extraction from the cells. When the inhibitors were individually examined, formic acid and furfural showed the highest extraction efficiency of lipids from wet cell mass. Multiple extractions of lipids with methanol from wet cell mass pretreated with combined common inhibitors or hardwood hydrolysate comprising lignocellulose-derived inhibitors resulted in lipid recovery of greater than 85% of total lipids, a 1.7-fold increase of lipid extraction as compared to those in the absence of the inhibitors.
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Affiliation(s)
- Kazuhiko Kurosawa
- Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
| | - C Anthony Debono
- Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
| | - Anthony J Sinskey
- Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Engineering Systems Division, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
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125
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Theuretzbacher F, Blomqvist J, Lizasoain J, Klietz L, Potthast A, Horn SJ, Nilsen PJ, Gronauer A, Passoth V, Bauer A. The effect of a combined biological and thermo-mechanical pretreatment of wheat straw on energy yields in coupled ethanol and methane generation. BIORESOURCE TECHNOLOGY 2015; 194:7-13. [PMID: 26176820 DOI: 10.1016/j.biortech.2015.06.093] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2015] [Revised: 06/19/2015] [Accepted: 06/20/2015] [Indexed: 05/11/2023]
Abstract
Ethanol and biogas are energy carriers that could contribute to a future energy system independent of fossil fuels. Straw is a favorable bioenergy substrate as it does not compete with food or feed production. As straw is very resistant to microbial degradation, it requires a pretreatment to insure efficient conversion to ethanol and/or methane. This study investigates the effect of combining biological pretreatment and steam explosion on ethanol and methane yields in order to improve the coupled generation process. Results show that the temperature of the steam explosion pretreatment has a particularly strong effect on possible ethanol yields, whereas combination with the biological pretreatment showed no difference in overall energy yield. The highest overall energy output was found to be 10.86 MJ kg VS(-1) using a combined biological and steam explosion pretreatment at a temperature of 200°C.
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Affiliation(s)
- Franz Theuretzbacher
- University of Natural Resources and Life Sciences, Department of Sustainable Agricultural Systems, Institute of Agricultural Engineering, Konrad-Lorenz-Strasse 24, A-3430 Tulln, Austria
| | - Johanna Blomqvist
- Swedish University of Agricultural Sciences, Uppsala BioCenter, Department of Chemistry and Biotechnology, P.O. Box 7015, 750 07 Uppsala, Sweden
| | - Javier Lizasoain
- University of Natural Resources and Life Sciences, Department of Sustainable Agricultural Systems, Institute of Agricultural Engineering, Konrad-Lorenz-Strasse 24, A-3430 Tulln, Austria; alpS - Centre for Climate Change Adaptation, Grabenweg 68, A-6010 Innsbruck, Austria
| | - Lena Klietz
- alpS - Centre for Climate Change Adaptation, Grabenweg 68, A-6010 Innsbruck, Austria
| | - Antje Potthast
- University of Natural Resources and Life Sciences, Department of Chemistry, Division of Organic Chemistry, Konrad-Lorenz-Strasse 24, A-3430 Tulln, Austria
| | - Svein Jarle Horn
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. Box 5003, N-1432 Ås, Norway
| | | | - Andreas Gronauer
- University of Natural Resources and Life Sciences, Department of Sustainable Agricultural Systems, Institute of Agricultural Engineering, Konrad-Lorenz-Strasse 24, A-3430 Tulln, Austria
| | - Volkmar Passoth
- Swedish University of Agricultural Sciences, Uppsala BioCenter, Department of Microbiology, P.O. Box 7025, 750 07 Uppsala, Sweden
| | - Alexander Bauer
- University of Natural Resources and Life Sciences, Department of Sustainable Agricultural Systems, Institute of Agricultural Engineering, Konrad-Lorenz-Strasse 24, A-3430 Tulln, Austria.
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126
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Cunha JT, Aguiar TQ, Romaní A, Oliveira C, Domingues L. Contribution of PRS3, RPB4 and ZWF1 to the resistance of industrial Saccharomyces cerevisiae CCUG53310 and PE-2 strains to lignocellulosic hydrolysate-derived inhibitors. BIORESOURCE TECHNOLOGY 2015; 191:7-16. [PMID: 25974617 DOI: 10.1016/j.biortech.2015.05.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 04/30/2015] [Accepted: 05/02/2015] [Indexed: 05/13/2023]
Abstract
PRS3, RPB4 and ZWF1 were previously identified as key genes for yeast tolerance to lignocellulose-derived inhibitors. To better understand their contribution to yeast resistance to the multiple stresses occurring during lignocellulosic hydrolysate fermentations, we overexpressed these genes in two industrial Saccharomyces cerevisiae strains, CCUG53310 and PE-2, and evaluated their impact on the fermentation of Eucalyptus globulus wood and corn cob hydrolysates. PRS3 overexpression improved the fermentation rate (up to 32%) and productivity (up to 48%) in different hydrolysates. ZWF1 and RPB4 overexpression did not improve the fermentation performance, but their increased expression in the presence of acetic acid, furfural and hydroxymethylfurfural was found to contribute to yeast adaptation to these inhibitors. This study expands our understanding about the molecular mechanisms involved in industrial yeast tolerance to the stresses occurring during lignocellulosic bioethanol production and highlights the importance of selecting appropriate strain backgrounds/hydrolysates combinations when addressing further improvement of these processes.
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Affiliation(s)
- Joana T Cunha
- CEB - Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
| | - Tatiana Q Aguiar
- CEB - Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
| | - Aloia Romaní
- CEB - Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
| | - Carla Oliveira
- CEB - Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
| | - Lucília Domingues
- CEB - Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal.
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127
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Austin S, Kontur WS, Ulbrich A, Oshlag Z, Zhang W, Higbee A, Zhang Y, Coon JJ, Hodge DB, Donohue TJ, Noguera DR. Metabolism of Multiple Aromatic Compounds in Corn Stover Hydrolysate by Rhodopseudomonas palustris. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:8914-22. [PMID: 26121369 PMCID: PMC5031247 DOI: 10.1021/acs.est.5b02062] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Lignocellulosic biomass hydrolysates hold great potential as a feedstock for microbial biofuel production, due to their high concentration of fermentable sugars. Present at lower concentrations are a suite of aromatic compounds that can inhibit fermentation by biofuel-producing microbes. We have developed a microbial-mediated strategy for removing these aromatic compounds, using the purple nonsulfur bacterium Rhodopseudomonas palustris. When grown photoheterotrophically in an anaerobic environment, R. palustris removes most of the aromatics from ammonia fiber expansion (AFEX) treated corn stover hydrolysate (ACSH), while leaving the sugars mostly intact. We show that R. palustris can metabolize a host of aromatic substrates in ACSH that have either been previously described as unable to support growth, such as methoxylated aromatics, and those that have not yet been tested, such as aromatic amides. Removing the aromatics from ACSH with R. palustris, allowed growth of a second microbe that could not grow in the untreated ACSH. By using defined mutants, we show that most of these aromatic compounds are metabolized by the benzoyl-CoA pathway. We also show that loss of enzymes in the benzoyl-CoA pathway prevents total degradation of the aromatics in the hydrolysate, and instead allows for biological transformation of this suite of aromatics into selected aromatic compounds potentially recoverable as an additional bioproduct.
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Affiliation(s)
- Samantha Austin
- Department of Civil and Environmental Engineering, University of Wisconsin–Madison, Madison, Wisconsin 53706, United States
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin–Madison, Madison, Wisconsin 53706, United States
| | - Wayne S. Kontur
- Department of Bacteriology, University of Wisconsin–Madison, Madison, Wisconsin 53706, United States
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin–Madison, Madison, Wisconsin 53706, United States
| | - Arne Ulbrich
- Department of Chemistry, University of Wisconsin–Madison, Madison, Wisconsin 53706, United States
| | - Zachary Oshlag
- Department of Civil and Environmental Engineering, University of Wisconsin–Madison, Madison, Wisconsin 53706, United States
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin–Madison, Madison, Wisconsin 53706, United States
| | - Weiping Zhang
- Department of Civil and Environmental Engineering, University of Wisconsin–Madison, Madison, Wisconsin 53706, United States
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin–Madison, Madison, Wisconsin 53706, United States
| | - Alan Higbee
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin–Madison, Madison, Wisconsin 53706, United States
- Department of Chemistry, University of Wisconsin–Madison, Madison, Wisconsin 53706, United States
| | - Yaoping Zhang
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin–Madison, Madison, Wisconsin 53706, United States
| | - Joshua J. Coon
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin–Madison, Madison, Wisconsin 53706, United States
- Department of Chemistry, University of Wisconsin–Madison, Madison, Wisconsin 53706, United States
- Department of Biomolecular Chemistry, University of Wisconsin–Madison, Madison, Wisconsin 53706, United States
| | - David B. Hodge
- Department of Chemical Engineering & Materials Science, Michigan State University, East Lansing, Michigan 48824, United States
- Department of Biosystems & Agricultural Engineering, Michigan State University, East Lansing, Michigan 48824, United States
| | - Timothy J. Donohue
- Department of Bacteriology, University of Wisconsin–Madison, Madison, Wisconsin 53706, United States
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin–Madison, Madison, Wisconsin 53706, United States
| | - Daniel R. Noguera
- Department of Civil and Environmental Engineering, University of Wisconsin–Madison, Madison, Wisconsin 53706, United States
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin–Madison, Madison, Wisconsin 53706, United States
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128
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Currie DH, Raman B, Gowen CM, Tschaplinski TJ, Land ML, Brown SD, Covalla SF, Klingeman DM, Yang ZK, Engle NL, Johnson CM, Rodriguez M, Shaw AJ, Kenealy WR, Lynd LR, Fong SS, Mielenz JR, Davison BH, Hogsett DA, Herring CD. Genome-scale resources for Thermoanaerobacterium saccharolyticum. BMC SYSTEMS BIOLOGY 2015; 9:30. [PMID: 26111937 PMCID: PMC4518999 DOI: 10.1186/s12918-015-0159-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 03/09/2015] [Indexed: 01/12/2023]
Abstract
Background Thermoanaerobacterium saccharolyticum is a hemicellulose-degrading thermophilic anaerobe that was previously engineered to produce ethanol at high yield. A major project was undertaken to develop this organism into an industrial biocatalyst, but the lack of genome information and resources were recognized early on as a key limitation. Results Here we present a set of genome-scale resources to enable the systems level investigation and development of this potentially important industrial organism. Resources include a complete genome sequence for strain JW/SL-YS485, a genome-scale reconstruction of metabolism, tiled microarray data showing transcription units, mRNA expression data from 71 different growth conditions or timepoints and GC/MS-based metabolite analysis data from 42 different conditions or timepoints. Growth conditions include hemicellulose hydrolysate, the inhibitors HMF, furfural, diamide, and ethanol, as well as high levels of cellulose, xylose, cellobiose or maltodextrin. The genome consists of a 2.7 Mbp chromosome and a 110 Kbp megaplasmid. An active prophage was also detected, and the expression levels of CRISPR genes were observed to increase in association with those of the phage. Hemicellulose hydrolysate elicited a response of carbohydrate transport and catabolism genes, as well as poorly characterized genes suggesting a redox challenge. In some conditions, a time series of combined transcription and metabolite measurements were made to allow careful study of microbial physiology under process conditions. As a demonstration of the potential utility of the metabolic reconstruction, the OptKnock algorithm was used to predict a set of gene knockouts that maximize growth-coupled ethanol production. The predictions validated intuitive strain designs and matched previous experimental results. Conclusion These data will be a useful asset for efforts to develop T. saccharolyticum for efficient industrial production of biofuels. The resources presented herein may also be useful on a comparative basis for development of other lignocellulose degrading microbes, such as Clostridium thermocellum. Electronic supplementary material The online version of this article (doi:10.1186/s12918-015-0159-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Devin H Currie
- Mascoma Corporation, 67 Etna Rd, 03766, Lebanon, NH, USA.
| | - Babu Raman
- BioEnergy Science Center, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN, 37831, USA. .,Dow AgroSciences, 9330 Zionsville Road, Indianapolis, IN, 46268, USA.
| | - Christopher M Gowen
- Chemical and Life Science Engineering, Virginia Commonwealth University, P.O. Box 843028, Richmond, Virginia, 23284, USA. .,Centre for Applied Bioscience and Bioengineering, Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Canada.
| | - Timothy J Tschaplinski
- BioEnergy Science Center, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN, 37831, USA.
| | - Miriam L Land
- BioEnergy Science Center, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN, 37831, USA.
| | - Steven D Brown
- BioEnergy Science Center, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN, 37831, USA.
| | - Sean F Covalla
- Mascoma Corporation, 67 Etna Rd, 03766, Lebanon, NH, USA.
| | - Dawn M Klingeman
- BioEnergy Science Center, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN, 37831, USA.
| | - Zamin K Yang
- BioEnergy Science Center, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN, 37831, USA.
| | - Nancy L Engle
- BioEnergy Science Center, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN, 37831, USA.
| | - Courtney M Johnson
- BioEnergy Science Center, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN, 37831, USA.
| | - Miguel Rodriguez
- BioEnergy Science Center, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN, 37831, USA.
| | - A Joe Shaw
- Mascoma Corporation, 67 Etna Rd, 03766, Lebanon, NH, USA. .,Novogy Inc, Cambridge, MA, 02138, USA.
| | | | - Lee R Lynd
- Mascoma Corporation, 67 Etna Rd, 03766, Lebanon, NH, USA. .,Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, NH, 03755, USA.
| | - Stephen S Fong
- Chemical and Life Science Engineering, Virginia Commonwealth University, P.O. Box 843028, Richmond, Virginia, 23284, USA.
| | - Jonathan R Mielenz
- BioEnergy Science Center, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN, 37831, USA.
| | - Brian H Davison
- BioEnergy Science Center, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN, 37831, USA.
| | | | - Christopher D Herring
- Mascoma Corporation, 67 Etna Rd, 03766, Lebanon, NH, USA. .,Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, NH, 03755, USA.
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Phenolic Amides Are Potent Inhibitors of De Novo Nucleotide Biosynthesis. Appl Environ Microbiol 2015; 81:5761-72. [PMID: 26070680 PMCID: PMC4551265 DOI: 10.1128/aem.01324-15] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 06/09/2015] [Indexed: 12/17/2022] Open
Abstract
An outstanding challenge toward efficient production of biofuels and value-added chemicals from plant biomass is the impact that lignocellulose-derived inhibitors have on microbial fermentations. Elucidating the mechanisms that underlie their toxicity is critical for developing strategies to overcome them. Here, using Escherichia coli as a model system, we investigated the metabolic effects and toxicity mechanisms of feruloyl amide and coumaroyl amide, the predominant phenolic compounds in ammonia-pretreated biomass hydrolysates. Using metabolomics, isotope tracers, and biochemical assays, we showed that these two phenolic amides act as potent and fast-acting inhibitors of purine and pyrimidine biosynthetic pathways. Feruloyl or coumaroyl amide exposure leads to (i) a rapid buildup of 5-phosphoribosyl-1-pyrophosphate (PRPP), a key precursor in nucleotide biosynthesis, (ii) a rapid decrease in the levels of pyrimidine biosynthetic intermediates, and (iii) a long-term generalized decrease in nucleotide and deoxynucleotide levels. Tracer experiments using 13C-labeled sugars and [15N]ammonia demonstrated that carbon and nitrogen fluxes into nucleotides and deoxynucleotides are inhibited by these phenolic amides. We found that these effects are mediated via direct inhibition of glutamine amidotransferases that participate in nucleotide biosynthetic pathways. In particular, feruloyl amide is a competitive inhibitor of glutamine PRPP amidotransferase (PurF), which catalyzes the first committed step in de novo purine biosynthesis. Finally, external nucleoside supplementation prevents phenolic amide-mediated growth inhibition by allowing nucleotide biosynthesis via salvage pathways. The results presented here will help in the development of strategies to overcome toxicity of phenolic compounds and facilitate engineering of more efficient microbial producers of biofuels and chemicals.
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Kurosawa K, Laser J, Sinskey AJ. Tolerance and adaptive evolution of triacylglycerol-producing Rhodococcus opacus to lignocellulose-derived inhibitors. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:76. [PMID: 26052344 PMCID: PMC4456722 DOI: 10.1186/s13068-015-0258-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 04/29/2015] [Indexed: 05/24/2023]
Abstract
BACKGROUND Lignocellulosic biomass has been investigated as a renewable non-food source for production of biofuels. A significant technical challenge to using lignocellulose is the presence of microbial growth inhibitors generated during pretreatment processes. Triacylglycerols (TAGs) are potential precursors for lipid-based biofuel production. Rhodococcus opacus MITXM-61 is an oleaginous bacterium capable of producing large amounts of TAGs on high concentrations of glucose and xylose present in lignocellulosic hydrolysates. However, this strain is sensitive to ligonocellulose-derived inhibitors. To understand the toxic effects of the inhibitors in lignocellulosic hydrolysates, strain MITXM-61 was examined for tolerance toward the potential inhibitors and was subjected to adaptive evolution for the resistance to the inhibitors. RESULTS We investigated growth-inhibitory effects by potential lignocellulose-derived inhibitors of phenols (lignin, vanillin, 4-hydroxybenzaldehyde (4-HB), syringaldehyde), furans (furfural and 5-hydroxymethyl-2-furaldehyde), and organic acids (levulinic acid, formic acid, and acetic acid) on the growth and TAG production of strain MITXM-61. Phenols and furans exhibited potent inhibitory effects at a concentration of 1 g L(-1), while organic acids had insignificant impacts at concentrations of up to 2 g L(-1). In an attempt to improve the inhibitor tolerance of strain MITXM-61, we evaluated the adaptation of this strain to the potential inhibitors. Adapted mutants were generated on defined agar media containing lignin, 4-HB, and syringaldehyde. Strain MITXM-61(SHL33) with improved multiple resistance of lignin, 4-HB, and syringaldehyde was constructed through adaptive evolution-based strategies. The evolved strain exhibited a two- to threefold increase in resistance to lignin, 4-HB, and syringaldehyde at 50% growth-inhibitory concentrations, compared to the parental strain. When grown in genuine lignocellulosic hydrolysates of corn stover, wheat straw, and hardwood containing growth inhibitors, strain MITXM-61(SHL33) exhibited a markedly shortened lag phase in comparison with that of strain MITXM-61. CONCLUSION This study provides important clues to overcome the negative effects of inhibitors in lignocellulosic hydrolysates on TAG production of R. opacus cells. The findings can contribute to significant progress in detoxified pretreatment of hydrolysates and development of more efficient strains for industrial TAG fermentations of R. opacus using lignocellulosic biomass.
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Affiliation(s)
- Kazuhiko Kurosawa
- />Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 USA
| | - Josephine Laser
- />Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 USA
- />Present address: Institute of Biotechnology, Department Applied and Molecular Microbiology Berlin University of Technology, Gustav-Meyer-Allee 25, Berlin, D-13355 Germany
| | - Anthony J Sinskey
- />Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 USA
- />Engineering Systems Division, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 USA
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131
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Compounds inhibiting the bioconversion of hydrothermally pretreated lignocellulose. Appl Microbiol Biotechnol 2015; 99:4201-12. [DOI: 10.1007/s00253-015-6595-0] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Revised: 04/06/2015] [Accepted: 04/09/2015] [Indexed: 01/02/2023]
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132
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Tan FR, Dai LC, Wu B, Qin H, Shui ZX, Wang JL, Zhu QL, Hu QC, Ruan ZY, He MX. Improving furfural tolerance of Zymomonas mobilis by rewiring a sigma factor RpoD protein. Appl Microbiol Biotechnol 2015; 99:5363-71. [PMID: 25895089 DOI: 10.1007/s00253-015-6577-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 03/23/2015] [Accepted: 03/25/2015] [Indexed: 01/21/2023]
Abstract
Furfural from lignocellulosic hydrolysates is the key inhibitor for bio-ethanol fermentation. In this study, we report a strategy of improving the furfural tolerance in Zymomonas mobilis on the transcriptional level by engineering its global transcription sigma factor (σ(70), RpoD) protein. Three furfural tolerance RpoD mutants (ZM4-MF1, ZM4-MF2, and ZM4-MF3) were identified from error-prone PCR libraries. The best furfural-tolerance strain ZM4-MF2 reached to the maximal cell density (OD600) about 2.0 after approximately 30 h, while control strain ZM4-rpoD reached its highest cell density of about 1.3 under the same conditions. ZM4-MF2 also consumed glucose faster and yield higher ethanol; expression levels and key Entner-Doudoroff (ED) pathway enzymatic activities were also compared to control strain under furfural stress condition. Our results suggest that global transcription machinery engineering could potentially be used to improve stress tolerance and ethanol production in Z. mobilis.
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Affiliation(s)
- Fu-Rong Tan
- Biogas Institute of Ministry of Agriculture, Biomass Energy Technology Research Centre, Section 4-13, Renming Nanlu, Chengdu, 610041, People's Republic of China
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Feldman D, Kowbel DJ, Glass NL, Yarden O, Hadar Y. Detoxification of 5-hydroxymethylfurfural by the Pleurotus ostreatus lignolytic enzymes aryl alcohol oxidase and dehydrogenase. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:63. [PMID: 25897324 PMCID: PMC4403834 DOI: 10.1186/s13068-015-0244-9] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 03/24/2015] [Indexed: 05/09/2023]
Abstract
BACKGROUND Current large-scale pretreatment processes for lignocellulosic biomass are generally accompanied by the formation of toxic degradation products, such as 5-hydroxymethylfurfural (HMF), which inhibit cellulolytic enzymes and fermentation by ethanol-producing yeast. Overcoming these toxic effects is a key technical barrier in the biochemical conversion of plant biomass to biofuels. Pleurotus ostreatus, a white-rot fungus, can efficiently degrade lignocellulose. In this study, we analyzed the ability of P. ostreatus to tolerate and metabolize HMF and investigated relevant molecular pathways associated with these processes. RESULTS P. ostreatus was capable to metabolize and detoxify HMF 30 mM within 48 h, converting it into 2,5-bis-hydroxymethylfuran (HMF alcohol) and 2,5-furandicarboxylic acid (FDCA), which subsequently allowed the normal yeast growth in amended media. We show that two enzymes groups, which belong to the ligninolytic system, aryl-alcohol oxidases and a dehydrogenase, are involved in this process. HMF induced the transcription and production of these enzymes and was accompanied by an increase in activity levels. We also demonstrate that following the induction of these enzymes, HMF could be metabolized in vitro. CONCLUSIONS Aryl-alcohol oxidase and dehydrogenase gene family members are part of the transcriptional and subsequent translational response to HMF exposure in P. ostreatus and are involved in HMF transformation. Based on our data, we propose that these enzymatic capacities of P. ostreatus either be integrated in biomass pretreatment or the genes encoding these enzymes may function to detoxify HMF via heterologous expression in fermentation organisms, such as Saccharomyces cerevisiae.
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Affiliation(s)
- Daria Feldman
- />Department of Plant Pathology and Microbiology, The R.H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, POB 12, Rehovot, 76100 Israel
| | - David J Kowbel
- />Department of Plant and Microbial Biology, University of California at Berkeley, 111 Koshland Hall, Berkeley, California 94720 USA
| | - N Louise Glass
- />Department of Plant and Microbial Biology, University of California at Berkeley, 111 Koshland Hall, Berkeley, California 94720 USA
| | - Oded Yarden
- />Department of Plant Pathology and Microbiology, The R.H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, POB 12, Rehovot, 76100 Israel
| | - Yitzhak Hadar
- />Department of Plant Pathology and Microbiology, The R.H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, POB 12, Rehovot, 76100 Israel
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134
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Fang Z, Liu X, Chen L, Shen Y, Zhang X, Fang W, Wang X, Bao X, Xiao Y. Identification of a laccase Glac15 from Ganoderma lucidum 77002 and its application in bioethanol production. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:54. [PMID: 25883681 PMCID: PMC4399389 DOI: 10.1186/s13068-015-0235-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 03/09/2015] [Indexed: 05/24/2023]
Abstract
BACKGROUND Laccases have potential applications in detoxification of lignocellulosic biomass after thermochemical pretreatment and production of value-added products or biofuels from renewable biomass. However, their application in large-scale industrial and environmental processes has been severely thwarted by the high cost of commercial laccases. Therefore, it is necessary to identify new laccases with lower cost but higher activity to detoxify lignocellulosic hydrolysates and better efficiency to produce biofuels such as bioethanol. Laccases from Ganoderma lucidum represent proper candidates in processing of lignocellulosic biomass. RESULTS G. lucidum 77002 produces three laccase isoenzymes with a total laccase activity of 141.1 U/mL within 6 days when using wheat bran and peanut powder as energy sources in liquid culture medium. A new isoenzyme named Glac15 was identified, purified, and characterized. Glac15 possesses an optimum pH of 4.5 to 5.0 and a temperature range of 45°C to 55°C for the substrates tested. It was stable at pH values ranging from 5.0 to 7.0 and temperatures lower than 55°C, with more than 80% activity retained after incubation for 2 h. When used in bioethanol production process, 0.05 U/mL Glac15 removed 84% of the phenolic compounds in prehydrolysate, and the yeast biomass reached 11.81 (optimal density at 600 nm (OD600)), compared to no growth in the untreated one. Addition of Glac15 before cellulase hydrolysis had no significant effect on glucose recovery. However, ethanol yield were improved in samples treated with laccases compared to that in control samples. The final ethanol concentration of 9.74, 10.05, 10.11, and 10.81 g/L were obtained from samples containing only solid content, solid content treated with Glac15, solid content containing 50% prehydrolysate, and solid content containing 50% prehydrolysate treated with Glac15, respectively. CONCLUSIONS The G. lucidum laccase Glac15 has potentials in bioethanol production industry.
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Affiliation(s)
- Zemin Fang
- />School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei, Anhui 230601 China
- />Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, 111 Jiulong Road, Hefei, Anhui 230601 China
| | - Xiaoman Liu
- />School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei, Anhui 230601 China
- />Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, 111 Jiulong Road, Hefei, Anhui 230601 China
| | - Liyuan Chen
- />The State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, 27 Shanda Nanlu, Jinan, Shandong 250100 China
| | - Yu Shen
- />The State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, 27 Shanda Nanlu, Jinan, Shandong 250100 China
| | - Xuecheng Zhang
- />School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei, Anhui 230601 China
- />Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, 111 Jiulong Road, Hefei, Anhui 230601 China
| | - Wei Fang
- />School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei, Anhui 230601 China
- />Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, 111 Jiulong Road, Hefei, Anhui 230601 China
| | - Xiaotang Wang
- />Department of Chemistry & Biochemistry, Florida International University, Miami, FL 33199 USA
| | - Xiaoming Bao
- />The State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, 27 Shanda Nanlu, Jinan, Shandong 250100 China
| | - Yazhong Xiao
- />School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei, Anhui 230601 China
- />Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, 111 Jiulong Road, Hefei, Anhui 230601 China
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135
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Kapoor RK, Rajan K, Carrier DJ. Applications of Trametes versicolor crude culture filtrates in detoxification of biomass pretreatment hydrolyzates. BIORESOURCE TECHNOLOGY 2015; 189:99-106. [PMID: 25876229 DOI: 10.1016/j.biortech.2015.03.100] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 03/20/2015] [Accepted: 03/21/2015] [Indexed: 06/04/2023]
Abstract
Laccases have wide range of substrate specificity and find applications from pulp industry to waste water remediation. Laccases have also been used in combined pretreatment of biomass hydrolyzates to remove enzymatic and fermentation inhibitors. In this study, laccase production by Trametes versicolor strains isolated from different regions of the United States was induced using copper salts. T. versicolor crude culture filtrates (CCF), without any purification step, were tested for removal of model inhibitor compounds as well as in poplar and rice straw pretreatment hydrolyzates. Phenolic inhibitors were removed by 76% and 94% from the dilute acid hydrolyzates of rice straw and poplar, respectively, when incubated with the CCF for 12h, at room temperature. Xylo-oligosaccharide concentrations present in rice straw hydrolyzates were reduced by 64% when incubated with T. versicolor CCF. T. versicolor CCF could be a low cost technology for decreasing enzymatic and fermentation inhibitors.
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Affiliation(s)
- Rajeev Kumar Kapoor
- Department of Microbiology, Maharshi Dayanand University, Rohtak, Haryana, India
| | - Kalavathy Rajan
- Department of Food Science, University of Arkansas, 2650 N Young Ave, Fayetteville, AR 72704, USA
| | - Danielle Julie Carrier
- Department of Biological and Agricultural Engineering, 203 White Engineering Hall, 1 University of Arkansas, Fayetteville, AR 72701, USA.
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136
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Kalyani D, Tiwari MK, Li J, Kim SC, Kalia VC, Kang YC, Lee JK. A highly efficient recombinant laccase from the yeast Yarrowia lipolytica and its application in the hydrolysis of biomass. PLoS One 2015; 10:e0120156. [PMID: 25781945 PMCID: PMC4363317 DOI: 10.1371/journal.pone.0120156] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 01/20/2015] [Indexed: 11/18/2022] Open
Abstract
A modified thermal asymmetric interlaced polymerase chain reaction was performed to obtain the first yeast laccase gene (YlLac) from the isolated yeast Yarrowia lipolytica. The 1557-bp full-length cDNA of YlLac encoded a mature laccase protein containing 519 amino acids preceded by a signal peptide of 19 amino acids, and the YlLac gene was expressed in the yeast Pichia pastoris. YlLac is a monomeric glycoprotein with a molecular mass of ~55 kDa as determined by polyacrylamide-gel electrophoresis. It showed a higher catalytic efficiency towards 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (kcat/Km = 17.5 s(-1) μM(-1)) and 2,6-dimethoxyphenol (kcat/Km = 16.1 s(-1) μM(-1)) than other reported laccases. The standard redox potential of the T1 site of the enzyme was found to be 772 mV. The highest catalytic efficiency of the yeast recombinant laccase, YlLac, makes it a good candidate for industrial applications: it removes phenolic compounds in acid-pretreated woody biomass (Populus balsamifera) and enhanced saccharification.
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Affiliation(s)
- Dayanand Kalyani
- Department of Chemical Engineering, Konkuk University, Seoul, Korea
| | | | - Jinglin Li
- Department of Chemical Engineering, Konkuk University, Seoul, Korea
| | - Sun Chang Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon, Korea
| | - Vipin C. Kalia
- Microbial Biotechnology and Genomics, CSIR-Institute of Genomics and Integrative Biology, Delhi University Campus, Delhi, India
| | - Yun Chan Kang
- Department of Materials Science and Engineering, Korea University, Anam-Dong, Seongbuk-Gu, Seoul, Korea
| | - Jung-Kul Lee
- Department of Chemical Engineering, Konkuk University, Seoul, Korea
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138
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Oliva-Taravilla A, Moreno AD, Demuez M, Ibarra D, Tomás-Pejó E, González-Fernández C, Ballesteros M. Unraveling the effects of laccase treatment on enzymatic hydrolysis of steam-exploded wheat straw. BIORESOURCE TECHNOLOGY 2015; 175:209-15. [PMID: 25459824 DOI: 10.1016/j.biortech.2014.10.086] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 10/16/2014] [Accepted: 10/17/2014] [Indexed: 05/02/2023]
Abstract
Laccase enzymes are promising detoxifying agents during lignocellulosic bioethanol production from wheat straw. However, they affect the enzymatic hydrolysis of this material by lowering the glucose recovery yields. This work aimed at explaining the negative effects of laccase on enzymatic hydrolysis. Relative glucose recovery in presence of laccase (10IU/g substrate) with model cellulosic substrate (Sigmacell) at 10% (w/v) was almost 10% points lower (P<0.01) than in the absence of laccase. This fact could be due to an increase in the competition of cellulose binding sites between the enzymes and a slight inhibition of β-glucosidase activity. However, enzymatic hydrolysis and infrared spectra of laccase-treated and untreated wheat straw filtered pretreated residue (WS-FPR), revealed that a grafting process of phenoxy radicals onto the lignin fiber could be the cause of diminished accessibility of cellulases to cellulose in pretreated wheat straw.
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Affiliation(s)
- Alfredo Oliva-Taravilla
- IMDEA Energy Institute, Biotechnology Processes for Energy Production Unit, 28935 Móstoles, Spain
| | - Antonio D Moreno
- IMDEA Energy Institute, Biotechnology Processes for Energy Production Unit, 28935 Móstoles, Spain
| | - Marie Demuez
- IMDEA Energy Institute, Biotechnology Processes for Energy Production Unit, 28935 Móstoles, Spain.
| | - David Ibarra
- INIA-CIFOR, Forestry Products Department, Cellulose and Paper Laboratories, 28040 Madrid, Spain
| | - Elia Tomás-Pejó
- IMDEA Energy Institute, Biotechnology Processes for Energy Production Unit, 28935 Móstoles, Spain
| | | | - Mercedes Ballesteros
- IMDEA Energy Institute, Biotechnology Processes for Energy Production Unit, 28935 Móstoles, Spain; CIEMAT, Renewable Energy Division, Biofuels Unit, 28040 Madrid, Spain
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139
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Wang X, Gao Q, Bao J. Transcriptional analysis of Amorphotheca resinae ZN1 on biological degradation of furfural and 5-hydroxymethylfurfural derived from lignocellulose pretreatment. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:136. [PMID: 26346604 PMCID: PMC4559888 DOI: 10.1186/s13068-015-0323-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 08/25/2015] [Indexed: 05/06/2023]
Abstract
BACKGROUND Furfural and 5-hydroxymethylfurfural (HMF) are the two major inhibitor compounds generated from lignocellulose pretreatment, especially for dilute acid, steam explosion, neutral hot water pretreatment methods. The two inhibitors severely inhibit the cell growth and metabolism of fermenting strains in the consequent bioconversion step. The biodetoxification strain Amorphotheca resinae ZN1 has demonstrated its extraordinary capacity of fast and complete degradation of furfural and HMF into corresponding alcohol and acid forms. The elucidation of degradation metabolism of A. resinae ZN1 at molecular level will facilitate the detoxification of the pretreated lignocellulose biomass and provide the metabolic pathway information for more powerful biodetoxification strain development. RESULTS Amorphotheca resinae ZN1 was able to use furfural or HMF as the sole carbon source for cell growth. During the detoxification process, A. resinae ZN1 firstly reduced furfural or HMF into furfuryl alcohol or HMF alcohol, and then oxidized into furoic acid or HMF acid through furan aldehyde as the intermediate at low concentration level. The cell mass measurement suggested that furfural was more toxic to A. resinae ZN1 than HMF. In order to identify the degradation mechanism of A. resinae ZN1, transcription levels of 137 putative genes involved in the degradation of furfural and HMF in A. resinae ZN1 were investigated using the real-time quantitative PCR (qRT-PCR) method under the stress of furfural and HMF, as well as the stress of their secondary metabolites, furfuryl alcohol and HMF alcohol. Two Zn-dependent alcohol dehydrogenase genes and five AKR/ARI genes were found to be responsible for the furfural and HMF conversion to their corresponding alcohols. For the conversion of the two furan alcohols to the corresponding acids, three propanol-preferring alcohol dehydrogenase genes, one NAD(P)(+)-depending aldehyde dehydrogenase gene, or two oxidase genes with free oxygen as the substrate were identified under aerobic condition. CONCLUSIONS The genes responsible for the furfural and HMF degradation to the corresponding alcohols and acids in A. resinae ZN1 were identified based on the analysis of the genome annotation, the gene transcription data and the inhibitor conversion results. These genetic resources provided the important information for understanding the mechanism of furfural and HMF degradation and modification of high tolerant strains used for biorefinery processing.
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Affiliation(s)
- Xia Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237 China
| | - Qiuqiang Gao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237 China
| | - Jie Bao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237 China
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140
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Current Trends in Bioethanol Production by Saccharomyces cerevisiae: Substrate, Inhibitor Reduction, Growth Variables, Coculture, and Immobilization. INTERNATIONAL SCHOLARLY RESEARCH NOTICES 2014; 2014:532852. [PMID: 27379305 PMCID: PMC4897133 DOI: 10.1155/2014/532852] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 11/18/2014] [Indexed: 11/24/2022]
Abstract
Bioethanol is one of the most commonly used biofuels in transportation sector to reduce greenhouse gases. S. cerevisiae is the most employed yeast for ethanol production at industrial level though ethanol is produced by an array of other yeasts, bacteria, and fungi. This paper reviews the current and nonmolecular trends in ethanol production using S. cerevisiae. Ethanol has been produced from wide range of substrates such as molasses, starch based substrate, sweet sorghum cane extract, lignocellulose, and other wastes. The inhibitors in lignocellulosic hydrolysates can be reduced by repeated sequential fermentation, treatment with reducing agents and activated charcoal, overliming, anion exchanger, evaporation, enzymatic treatment with peroxidase and laccase, in situ detoxification by fermenting microbes, and different extraction methods. Coculturing S. cerevisiae with other yeasts or microbes is targeted to optimize ethanol production, shorten fermentation time, and reduce process cost. Immobilization of yeast cells has been considered as potential alternative for enhancing ethanol productivity, because immobilizing yeasts reduce risk of contamination, make the separation of cell mass from the bulk liquid easy, retain stability of cell activities, minimize production costs, enable biocatalyst recycling, reduce fermentation time, and protect the cells from inhibitors. The effects of growth variables of the yeast and supplementation of external nitrogen sources on ethanol optimization are also reviewed.
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141
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Sophorolipid Production from Biomass Hydrolysates. Appl Biochem Biotechnol 2014; 175:2246-57. [DOI: 10.1007/s12010-014-1425-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 11/18/2014] [Indexed: 11/25/2022]
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142
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Shi X, Chen Y, Ren H, Liu D, Zhao T, Zhao N, Ying H. Economically enhanced succinic acid fermentation from cassava bagasse hydrolysate using Corynebacterium glutamicum immobilized in porous polyurethane filler. BIORESOURCE TECHNOLOGY 2014; 174:190-7. [PMID: 25463799 DOI: 10.1016/j.biortech.2014.09.137] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 09/25/2014] [Accepted: 09/26/2014] [Indexed: 05/25/2023]
Abstract
An immobilized fermentation system, using cassava bagasse hydrolysate (CBH) and mixed alkalis, was developed to achieve economical succinic acid production by Corynebacterium glutamicum. The C. glutamicum strains were immobilized in porous polyurethane filler (PPF). CBH was used efficiently as a carbon source instead of more expensive glucose. Moreover, as a novel method for regulating pH, the easily decomposing NaHCO3 was replaced by mixed alkalis (NaOH and Mg(OH)2) for succinic acid production by C. glutamicum. Using CBH and mixed alkalis in the immobilized batch fermentation system, succinic acid productivity of 0.42gL(-1)h(-1) was obtained from 35gL(-1) glucose of CBH, which is similar to that obtained with conventional free-cell fermentation with glucose and NaHCO3. In repeated batch fermentation, an average of 22.5gL(-1) succinic acid could be obtained from each batch, which demonstrated the enhanced stability of the immobilized C. glutamicum cells.
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Affiliation(s)
- Xinchi Shi
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Life Science and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing 210009, PR China
| | - Yong Chen
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Life Science and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing 210009, PR China
| | - Hengfei Ren
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Life Science and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing 210009, PR China
| | - Dong Liu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Life Science and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing 210009, PR China
| | - Ting Zhao
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Life Science and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing 210009, PR China
| | - Nan Zhao
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Life Science and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing 210009, PR China
| | - Hanjie Ying
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Life Science and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing 210009, PR China.
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143
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Choi SY, Gong G, Park HS, Um Y, Sim SJ, Woo HM. Extreme furfural tolerance of a soil bacterium Enterobacter cloacae GGT036. J Biotechnol 2014; 193:11-3. [PMID: 25444876 DOI: 10.1016/j.jbiotec.2014.11.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 10/29/2014] [Accepted: 11/03/2014] [Indexed: 10/24/2022]
Abstract
Detoxification process of cellular inhibitors including furfural is essential for production of bio-based chemicals from lignocellulosic biomass. Here we isolated an extreme furfural-tolerant bacterium Enterobacter cloacae GGT036 from soil sample collected in Mt. Gwanak, Republic of Korea. Among isolated bacteria, only E. cloacae GGT036 showed cell growth with 35 mM furfural under aerobic culture. Compared to the maximal half inhibitory concentration (IC50) of well-known industrial strains Escherichia coli (24.9 mM furfural) and Corynebacterium glutamicum (10 mM furfural) based on the cell density, IC50 of E. cloacae GGT036 (47.7 mM) was significantly higher after 24 h, compared to E. coli and C. glutamicum. Since bacterial cell growth was exponentially inhibited depending on linearly increased furfural concentrations in the medium, we concluded that E. cloacae GGT036 is an extreme furfural-tolerant bacterium. Recently, the complete genome sequence of E. cloacae GGT036 was announced and this could provide an insight for engineering of E. cloacae GGT036 itself or other industrially relevant bacteria.
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Affiliation(s)
- Sun Young Choi
- Clean Energy Research Center, Korea Institute of Science and Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 136-791, Republic of Korea; Green School (Graduate School of Energy and Environment), 145 Anam-ro, Seongbuk-gu, Seoul, Republic of Korea
| | - Gyeongtaek Gong
- Clean Energy Research Center, Korea Institute of Science and Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 136-791, Republic of Korea
| | - Hong-Sil Park
- Clean Energy Research Center, Korea Institute of Science and Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 136-791, Republic of Korea; Green School (Graduate School of Energy and Environment), 145 Anam-ro, Seongbuk-gu, Seoul, Republic of Korea
| | - Youngsoon Um
- Clean Energy Research Center, Korea Institute of Science and Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 136-791, Republic of Korea; Department of Clean Energy and Chemical Engineering, Korea University of Science and Technology, 217 Gajeong-ro, Yuseong-gu, Daejeon 305-350, Republic of Korea
| | - Sang Jun Sim
- Green School (Graduate School of Energy and Environment), 145 Anam-ro, Seongbuk-gu, Seoul, Republic of Korea; Department of Chemical and Biological Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul, Republic of Korea
| | - Han Min Woo
- Clean Energy Research Center, Korea Institute of Science and Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 136-791, Republic of Korea; Green School (Graduate School of Energy and Environment), 145 Anam-ro, Seongbuk-gu, Seoul, Republic of Korea; Department of Clean Energy and Chemical Engineering, Korea University of Science and Technology, 217 Gajeong-ro, Yuseong-gu, Daejeon 305-350, Republic of Korea.
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144
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Manzano-Robleda MDC, Barranco-Fragoso B, Uribe M, Méndez-Sánchez N. Portal vein thrombosis: what is new? Ann Hepatol 2014; 71:2-7. [PMID: 25536638 DOI: 10.1016/j.ijbiomac.2014.06.065] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 05/28/2014] [Accepted: 06/11/2014] [Indexed: 02/06/2023]
Abstract
Portal vein thrombosis (PVT) is one of the most common vascular disorders of the liver with significant morbidity and mortality. Large cohort studies have reported a global prevalence of 1%, but in some risk groups it can be up to 26%. Causes of PVT are cirrhosis, hepatobiliary malignancy, abdominal infectious or inflammatory diseases, and myeloproliferative disorders. Most patients with PVT have a general risk factor. The natural history of PVT results in portal hypertension leading to splenomegaly and the formation of portosystemic collateral blood vessels and esophageal, gastric, duodenal, and jejunal varices. Diagnosis of PVT is made by imaging, mainly Doppler ultrasonography. According to its time of development, localization, pathophysiology, and evolution, PVT should be classified in every patient. Some clinical features such as cirrhosis, hepatocellular carcinoma, and hepatic transplantation are areas of special interest and are discussed in this review. The goal of treatment of acute PVT is to reconstruct the blocked veins. Endoscopic variceal ligation is safe and highly effective in patients with variceal bleeding caused by chronic PVT. In conclusion, PVT is the most common cause of vascular disease of the liver and its prevalence has being increasing, especially among patients with an underlying liver disease. All patients should be investigated for thrombophilic conditions, and in those with cirrhosis, anticoagulation prophylaxis should be considered.
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Affiliation(s)
| | | | - Misael Uribe
- Liver Research Unit. Medica Sur Clinic & Foundation. Mexico City, Mexico
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145
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Albuquerque TLD, da Silva IJ, de Macedo GR, Rocha MVP. Biotechnological production of xylitol from lignocellulosic wastes: A review. Process Biochem 2014. [DOI: 10.1016/j.procbio.2014.07.010] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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146
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Sitepu IR, Garay LA, Sestric R, Levin D, Block DE, German JB, Boundy-Mills KL. Oleaginous yeasts for biodiesel: Current and future trends in biology and production. Biotechnol Adv 2014; 32:1336-1360. [DOI: 10.1016/j.biotechadv.2014.08.003] [Citation(s) in RCA: 251] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2014] [Revised: 07/25/2014] [Accepted: 08/18/2014] [Indexed: 10/24/2022]
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147
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Utilization of economical substrate-derived carbohydrates by solventogenic clostridia: pathway dissection, regulation and engineering. Curr Opin Biotechnol 2014; 29:124-31. [DOI: 10.1016/j.copbio.2014.04.004] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Revised: 03/21/2014] [Accepted: 04/02/2014] [Indexed: 01/15/2023]
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148
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Bauer A, Lizasoain J, Theuretzbacher F, Agger JW, Rincón M, Menardo S, Saylor MK, Enguídanos R, Nielsen PJ, Potthast A, Zweckmair T, Gronauer A, Horn SJ. Steam explosion pretreatment for enhancing biogas production of late harvested hay. BIORESOURCE TECHNOLOGY 2014; 166:403-10. [PMID: 24929812 DOI: 10.1016/j.biortech.2014.05.025] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 05/07/2014] [Accepted: 05/11/2014] [Indexed: 05/05/2023]
Abstract
Grasslands are often abandoned due to lack of profitability. Extensively cultivating grassland for utilization in a biogas-based biorefinery concept could mend this problem. Efficient bioconversion of this lignocellulosic biomass requires a pretreatment step. In this study the effect of different steam explosion conditions on hay digestibility have been investigated. Increasing severity in the pretreatment induced degradation of the hemicellulose, which at the same time led to the production of inhibitors and formation of pseudo-lignin. Enzymatic hydrolysis showed that the maximum glucose yields were obtained under pretreatment at 220 °C for 15 min, while higher xylose yields were obtained at 175 °C for 10 min. Pretreatment of hay by steam explosion enhanced 15.9% the methane yield in comparison to the untreated hay. Results indicate that hay can be effectively converted to methane after steam explosion pretreatment.
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Affiliation(s)
- Alexander Bauer
- University of Natural Resources and Life Sciences, Department of Sustainable Agricultural Systems, Institute of Agricultural Engineering, Konrad-Lorenz-Strasse 24, A-3430 Tulln, Austria; AlpS-GmbH, Centre for Climate Change Adaptation Technologies, Grabenweg 68, A-6010 Innsbruck, Austria.
| | - Javier Lizasoain
- University of Natural Resources and Life Sciences, Department of Sustainable Agricultural Systems, Institute of Agricultural Engineering, Konrad-Lorenz-Strasse 24, A-3430 Tulln, Austria; AlpS-GmbH, Centre for Climate Change Adaptation Technologies, Grabenweg 68, A-6010 Innsbruck, Austria
| | - Franz Theuretzbacher
- University of Natural Resources and Life Sciences, Department of Sustainable Agricultural Systems, Institute of Agricultural Engineering, Konrad-Lorenz-Strasse 24, A-3430 Tulln, Austria
| | - Jane W Agger
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. Box 5003, N-1432 Ås, Norway
| | - María Rincón
- University of Natural Resources and Life Sciences, Department of Sustainable Agricultural Systems, Institute of Agricultural Engineering, Konrad-Lorenz-Strasse 24, A-3430 Tulln, Austria
| | - Simona Menardo
- AlpS-GmbH, Centre for Climate Change Adaptation Technologies, Grabenweg 68, A-6010 Innsbruck, Austria; Mechanics Section, Department of Agricultural, Forest and Food Sciences (DISAFA), University of Torino, largo Paolo Braccini 2, 10095 Grugliasco, Torino, Italy
| | - Molly K Saylor
- AlpS-GmbH, Centre for Climate Change Adaptation Technologies, Grabenweg 68, A-6010 Innsbruck, Austria
| | - Ramón Enguídanos
- University of Natural Resources and Life Sciences, Department of Sustainable Agricultural Systems, Institute of Agricultural Engineering, Konrad-Lorenz-Strasse 24, A-3430 Tulln, Austria
| | | | - Antje Potthast
- University of Natural Resources and Life Sciences, Department of Chemistry, Institute of Chemistry of Renewable Resources, Konrad-Lorenz-Strasse 24, A-3430 Tulln, Austria
| | - Thomas Zweckmair
- University of Natural Resources and Life Sciences, Department of Chemistry, Institute of Chemistry of Renewable Resources, Konrad-Lorenz-Strasse 24, A-3430 Tulln, Austria
| | - Andreas Gronauer
- University of Natural Resources and Life Sciences, Department of Sustainable Agricultural Systems, Institute of Agricultural Engineering, Konrad-Lorenz-Strasse 24, A-3430 Tulln, Austria
| | - Svein J Horn
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. Box 5003, N-1432 Ås, Norway
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149
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Wallace-Salinas V, Signori L, Li YY, Ask M, Bettiga M, Porro D, Thevelein JM, Branduardi P, Foulquié-Moreno MR, Gorwa-Grauslund M. Re-assessment of YAP1 and MCR1 contributions to inhibitor tolerance in robust engineered Saccharomyces cerevisiae fermenting undetoxified lignocellulosic hydrolysate. AMB Express 2014; 4:56. [PMID: 25147754 PMCID: PMC4105880 DOI: 10.1186/s13568-014-0056-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 06/19/2014] [Indexed: 11/10/2022] Open
Abstract
Development of robust yeast strains that can efficiently ferment lignocellulose-based feedstocks is one of the requirements for achieving economically feasible bioethanol production processes. With this goal, several genes have been identified as promising candidates to confer improved tolerance to S. cerevisiae. In most of the cases, however, the evaluation of the genetic modification was performed only in laboratory strains, that is, in strains that are known to be quite sensitive to various types of stresses. In the present study, we evaluated the effects of overexpressing genes encoding the transcription factor (YAP1) and the mitochondrial NADH-cytochrome b5 reductase (MCR1), either alone or in combination, in an already robust and xylose-consuming industrial strain of S. cerevisiae and evaluated the effect during the fermentation of undiluted and undetoxified spruce hydrolysate. Overexpression of either gene resulted in faster hexose catabolism, but no cumulative effect was observed with the simultaneous overexpression. The improved phenotype of MCR1 overexpression appeared to be related, at least in part, to a faster furaldehyde reduction capacity, indicating that this reductase may have a wider substrate range than previously reported. Unexpectedly a decreased xylose fermentation rate was also observed in YAP1 overexpressing strains and possible reasons behind this phenotype are discussed.
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150
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Magnetic cross-linked enzyme aggregates (CLEAs): A novel concept towards carrier free immobilization of lignocellulolytic enzymes. Enzyme Microb Technol 2014; 61-62:17-27. [DOI: 10.1016/j.enzmictec.2014.04.009] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 04/10/2014] [Accepted: 04/17/2014] [Indexed: 11/21/2022]
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