1
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Saxena A, Hussain A, Parveen F, Ashfaque M. Current status of metabolic engineering of microorganisms for bioethanol production by effective utilization of pentose sugars of lignocellulosic biomass. Microbiol Res 2023; 276:127478. [PMID: 37625339 DOI: 10.1016/j.micres.2023.127478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 08/01/2023] [Accepted: 08/09/2023] [Indexed: 08/27/2023]
Abstract
Lignocellulosic biomass, consisting of homo- and heteropolymeric sugars, acts as a substrate for the generation of valuable biochemicals and biomaterials. The readily available hexoses are easily utilized by microbes due to the presence of transporters and native metabolic pathways. But, utilization of pentose sugar viz., xylose and arabinose are still challenging due to several reasons including (i) the absence of the particular native pathways and transporters, (ii) the presence of inhibitors, and (iii) lower uptake of pentose sugars. These challenges can be overcome by manipulating metabolic pathways/glycosidic enzymes cascade by using genetic engineering tools involving inverse-metabolic engineering, ex-vivo isomerization, Adaptive Laboratory Evolution, Directed Metabolic Engineering, etc. Metabolic engineering of bacteria and fungi for the utilization of pentose sugars for bioethanol production is the focus area of research in the current decade. This review outlines current approaches to biofuel development and strategies involved in the metabolic engineering of different microbes that can uptake pentose for bioethanol production.
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Affiliation(s)
- Ayush Saxena
- Lignocellulose & Biofuel Laboratory, Department of Biosciences, Integral University, Lucknow 226026, Uttar Pradesh, India.
| | - Akhtar Hussain
- Lignocellulose & Biofuel Laboratory, Department of Biosciences, Integral University, Lucknow 226026, Uttar Pradesh, India.
| | - Fouziya Parveen
- Lignocellulose & Biofuel Laboratory, Department of Biosciences, Integral University, Lucknow 226026, Uttar Pradesh, India.
| | - Mohammad Ashfaque
- Lignocellulose & Biofuel Laboratory, Department of Biosciences, Integral University, Lucknow 226026, Uttar Pradesh, India.
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2
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Osiebe O, Adewale IO, Omafuvbe BO. Intracellular invertase hyperproducing strain of Saccharomyces cerevisiae isolated from Abagboro palm wine. Sci Rep 2023; 13:4937. [PMID: 36973340 PMCID: PMC10043029 DOI: 10.1038/s41598-023-32289-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 03/25/2023] [Indexed: 03/29/2023] Open
Abstract
There is an ever-increasing demand for industrial enzyme, necessitating a constant search for its efficient producers. The isolation and characterization of invertase producer yeasts from natural palm wine is reported in this study. Yeasts were isolated from fresh palm wine obtained from Abagboro community Ile-Ife, Nigeria following standard methods. A total of six yeast strains were isolated from the palm wine. The strains were screened for their ability to produce invertase and the most efficient invertase producer was characterized and identified using phenotypic and molecular methods. Isolate C showed the highest invertase activity (34.15 µmole/ml/min), followed by isolate B (18.070 µmole/ml/min) and isolate A (14.385 µmole/ml/min). The identity of isolate C was confirmed by genotypic methods to be Saccharomyces cerevisiae (OL629078.1 accession number on NCBI database). The Saccharomyces cerevisiae strain fermented galactose, arabinose, maltose, glucose, sucrose and raffinose, grew in 50% and 60% glucose and at 25-35 °C. The newly isolated Saccharomyces cerevisiae strain is an efficient producer of invertase and can be exploited for commercial biosynthesis of the enzyme for use in biotechnological applications.
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Affiliation(s)
- Oghenesivwe Osiebe
- Department of Biochemistry and Molecular Biology, Obafemi Awolowo University, Ile-Ife, Nigeria.
| | - Isaac Olusanjo Adewale
- Department of Biochemistry and Molecular Biology, Obafemi Awolowo University, Ile-Ife, Nigeria
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3
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Soares-Silva I, Ribas D, Sousa-Silva M, Azevedo-Silva J, Rendulić T, Casal M. Membrane transporters in the bioproduction of organic acids: state of the art and future perspectives for industrial applications. FEMS Microbiol Lett 2021; 367:5873408. [PMID: 32681640 PMCID: PMC7419537 DOI: 10.1093/femsle/fnaa118] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 07/17/2020] [Indexed: 12/16/2022] Open
Abstract
Organic acids such as monocarboxylic acids, dicarboxylic acids or even more complex molecules such as sugar acids, have displayed great applicability in the industry as these compounds are used as platform chemicals for polymer, food, agricultural and pharmaceutical sectors. Chemical synthesis of these compounds from petroleum derivatives is currently their major source of production. However, increasing environmental concerns have prompted the production of organic acids by microorganisms. The current trend is the exploitation of industrial biowastes to sustain microbial cell growth and valorize biomass conversion into organic acids. One of the major bottlenecks for the efficient and cost-effective bioproduction is the export of organic acids through the microbial plasma membrane. Membrane transporter proteins are crucial elements for the optimization of substrate import and final product export. Several transporters have been expressed in organic acid-producing species, resulting in increased final product titers in the extracellular medium and higher productivity levels. In this review, the state of the art of plasma membrane transport of organic acids is presented, along with the implications for industrial biotechnology.
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Affiliation(s)
- I Soares-Silva
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal.,Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus de Gualtar, Braga 4710-057, Portugal
| | - D Ribas
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal.,Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus de Gualtar, Braga 4710-057, Portugal
| | - M Sousa-Silva
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal.,Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus de Gualtar, Braga 4710-057, Portugal
| | - J Azevedo-Silva
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal.,Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus de Gualtar, Braga 4710-057, Portugal
| | - T Rendulić
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal.,Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus de Gualtar, Braga 4710-057, Portugal
| | - M Casal
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal.,Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus de Gualtar, Braga 4710-057, Portugal
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4
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Ruchala J, Sibirny AA. Pentose metabolism and conversion to biofuels and high-value chemicals in yeasts. FEMS Microbiol Rev 2020; 45:6034013. [PMID: 33316044 DOI: 10.1093/femsre/fuaa069] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 12/09/2020] [Indexed: 12/15/2022] Open
Abstract
Pentose sugars are widespread in nature and two of them, D-xylose and L-arabinose belong to the most abundant sugars being the second and third by abundance sugars in dry plant biomass (lignocellulose) and in general on planet. Therefore, it is not surprising that metabolism and bioconversion of these pentoses attract much attention. Several different pathways of D-xylose and L-arabinose catabolism in bacteria and yeasts are known. There are even more common and really ubiquitous though not so abundant pentoses, D-ribose and 2-deoxy-D-ribose, the constituents of all living cells. Thus, ribose metabolism is example of endogenous metabolism whereas metabolism of other pentoses, including xylose and L-arabinose, represents examples of the metabolism of foreign exogenous compounds which normally are not constituents of yeast cells. As a rule, pentose degradation by the wild-type strains of microorganisms does not lead to accumulation of high amounts of valuable substances; however, productive strains have been obtained by random selection and metabolic engineering. There are numerous reviews on xylose and (less) L-arabinose metabolism and conversion to high value substances; however, they mostly are devoted to bacteria or the yeast Saccharomyces cerevisiae. This review is devoted to reviewing pentose metabolism and bioconversion mostly in non-conventional yeasts, which naturally metabolize xylose. Pentose metabolism in the recombinant strains of S. cerevisiae is also considered for comparison. The available data on ribose, xylose, L-arabinose transport, metabolism, regulation of these processes, interaction with glucose catabolism and construction of the productive strains of high-value chemicals or pentose (ribose) itself are described. In addition, genome studies of the natural xylose metabolizing yeasts and available tools for their molecular research are reviewed. Metabolism of other pentoses (2-deoxyribose, D-arabinose, lyxose) is briefly reviewed.
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Affiliation(s)
- Justyna Ruchala
- Department of Microbiology and Molecular Genetics, University of Rzeszow, Zelwerowicza 4, Rzeszow 35-601, Poland.,Department of Molecular Genetics and Biotechnology, Institute of Cell Biology NAS of Ukraine, Drahomanov Street, 14/16, Lviv 79005, Ukraine
| | - Andriy A Sibirny
- Department of Microbiology and Molecular Genetics, University of Rzeszow, Zelwerowicza 4, Rzeszow 35-601, Poland.,Department of Molecular Genetics and Biotechnology, Institute of Cell Biology NAS of Ukraine, Drahomanov Street, 14/16, Lviv 79005, Ukraine
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5
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Fu C, Liu X, Li X, Huo P, Ge J, Hou Y, Yang W, Zhang J, Zhang L, Zhao D, Ma C, Liu J. BRF Negatively Regulates Thermotolerance Defect of fes1a in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2020; 11:171. [PMID: 32210987 PMCID: PMC7077510 DOI: 10.3389/fpls.2020.00171] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 02/05/2020] [Indexed: 06/10/2023]
Abstract
FES1A is a heat shock protein 70 binding protein. Mutation of FES1A leads to a defect in thermotolerance of Arabidopsis; however, independent fes1a mutants exhibit a range in the extent of thermosensitivity. Here, we found that BRF2, a gene adjacent to FES1A and encoding a component of transcription factor IIIB, affects the thermosensitivity of fes1a mutants. Knockout of BRF2 suppressed fes1a thermosensitivity, while overexpression of BRF2 increased thermosensitivity of fes1a. BRF2 in fes1a mutants regulates the transcriptional strength of RNA Polymerase II and accumulation of heat shock proteins and eventually affects the thermotolerance of fes1a. There is a cross-talking between RNA Pol III and Pol II. The cross-talking is initiated by BRF, magnified by the mutation of FES1A, and finally has an effect on thermotolerance.
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Affiliation(s)
- Can Fu
- College of Life Sciences, Shandong Normal University, Jinan, China
| | - Xiaxia Liu
- College of Life Sciences, Shandong Normal University, Jinan, China
| | - Xuezhi Li
- College of Life Sciences, Shandong Normal University, Jinan, China
| | - Panfei Huo
- College of Life Sciences, Shandong Normal University, Jinan, China
| | - Jingjing Ge
- College of Life Sciences, Shandong Normal University, Jinan, China
| | - Yanfei Hou
- College of Life Sciences, Shandong Normal University, Jinan, China
| | - Wenwen Yang
- College of Life Sciences, Shandong Normal University, Jinan, China
| | - Jingxia Zhang
- Cotton Research Center, Shandong Academy of Agricultural Sciences, Jinan, China
| | - Limin Zhang
- College of Life Sciences, Shandong Normal University, Jinan, China
| | - Dazhong Zhao
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - Changle Ma
- College of Life Sciences, Shandong Normal University, Jinan, China
| | - Jian Liu
- College of Life Sciences, Shandong Normal University, Jinan, China
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6
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Nijland JG, Driessen AJM. Engineering of Pentose Transport in Saccharomyces cerevisiae for Biotechnological Applications. Front Bioeng Biotechnol 2020; 7:464. [PMID: 32064252 PMCID: PMC7000353 DOI: 10.3389/fbioe.2019.00464] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 12/19/2019] [Indexed: 01/05/2023] Open
Abstract
Lignocellulosic biomass yields after hydrolysis, besides the hexose D-glucose, D-xylose, and L-arabinose as main pentose sugars. In second generation bioethanol production utilizing the yeast Saccharomyces cerevisiae, it is critical that all three sugars are co-consumed to obtain an economically feasible and robust process. Since S. cerevisiae is unable to metabolize pentose sugars, metabolic pathway engineering has been employed to introduce the respective pathways for D-xylose and L-arabinose metabolism. However, S. cerevisiae lacks specific pentose transporters, and these sugars enter the cell with low affinity via glucose transporters of the Hxt family. Therefore, in the presence of D-glucose, utilization of D-xylose and L-arabinose is poor as the Hxt transporters prefer D-glucose. To solve this problem, heterologous expression of pentose transporters has been attempted but often with limited success due to poor expression and stability, and/or low turnover. A more successful approach is the engineering of the endogenous Hxt transporter family and evolutionary selection for D-glucose insensitive growth on pentose sugars. This has led to the identification of a critical and conserved asparagine residue in Hxt transporters that, when mutated, reduces the D-glucose affinity while leaving the D-xylose affinity mostly unaltered. Likewise, mutant Gal2 transporter have been selected supporting specific uptake of L-arabinose. In fermentation experiments, the transporter mutants support efficient uptake and consumption of pentose sugars, and even co-consumption of D-xylose and D-glucose when used at industrial concentrations. Further improvements are obtained by interfering with the post-translational inactivation of Hxt transporters at high or low D-glucose concentrations. Transporter engineering solved major limitations in pentose transport in yeast, now allowing for co-consumption of sugars that is limited only by the rates of primary metabolism. This paves the way for a more economical second-generation biofuels production process.
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Affiliation(s)
- Jeroen G Nijland
- Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology, University of Groningen, Groningen, Netherlands
| | - Arnold J M Driessen
- Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology, University of Groningen, Groningen, Netherlands
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7
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Ye S, Jeong D, Shon JC, Liu KH, Kim KH, Shin M, Kim SR. Deletion of PHO13 improves aerobic L-arabinose fermentation in engineered Saccharomyces cerevisiae. J Ind Microbiol Biotechnol 2019; 46:1725-1731. [PMID: 31501960 DOI: 10.1007/s10295-019-02233-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 08/31/2019] [Indexed: 10/26/2022]
Abstract
Pentose sugars are increasingly being used in industrial applications of Saccharomyces cerevisiae. Although L-arabinose is a highlighted pentose that has been identified as next-generation biomass, arabinose fermentation has not yet undergone extensive development for industrial utilization. In this study, we integrated a heterologous fungal arabinose pathway with a deletion of PHO13 phosphatase gene. PHO13 deletion increased arabinose consumption rate and specific ethanol productivity under aerobic conditions and consequently depleted sedoheptulose by activation of the TAL1 gene. Global metabolite profiling indicated upregulation of the pentose phosphate pathway and downstream effects such as trehalose accumulation and downregulation of the TCA cycle. Our results suggest that engineering of PHO13 has ample potential for arabinose conversion to ethanol as an industrial source for biofuels.
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Affiliation(s)
- Suji Ye
- School of Food Science and Biotechnology, Kyungpook National University, Daegu, Republic of Korea
| | - Deokyeol Jeong
- School of Food Science and Biotechnology, Kyungpook National University, Daegu, Republic of Korea
| | - Jong Cheol Shon
- Department of Environmental Toxicology Research Center, Korea Institute of Toxicology, Jinju, Republic of Korea.,College of Pharmacy and Research Institute of Pharmaceutical Sciences, Kyungpook National University, Daegu, Republic of Korea
| | - Kwang-Hyeon Liu
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Kyungpook National University, Daegu, Republic of Korea
| | - Kyoung Heon Kim
- Department of Biotechnology, Graduate School, Korea University, Seoul, Republic of Korea
| | - Minhye Shin
- Department of Biotechnology, Graduate School, Korea University, Seoul, Republic of Korea.
| | - Soo Rin Kim
- School of Food Science and Biotechnology, Kyungpook National University, Daegu, Republic of Korea.
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Verhoeven MD, Bracher JM, Nijland JG, Bouwknegt J, Daran JMG, Driessen AJM, van Maris AJA, Pronk JT. Laboratory evolution of a glucose-phosphorylation-deficient, arabinose-fermenting S. cerevisiae strain reveals mutations in GAL2 that enable glucose-insensitive l-arabinose uptake. FEMS Yeast Res 2019; 18:5026172. [PMID: 29860442 PMCID: PMC6044391 DOI: 10.1093/femsyr/foy062] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 05/30/2018] [Indexed: 12/28/2022] Open
Abstract
Cas9-assisted genome editing was used to construct an engineered glucose-phosphorylation-negative S. cerevisiae strain, expressing the Lactobacillus plantaruml-arabinose pathway and the Penicillium chrysogenum transporter PcAraT. This strain, which showed a growth rate of 0.26 h−1 on l-arabinose in aerobic batch cultures, was subsequently evolved for anaerobic growth on l-arabinose in the presence of d-glucose and d-xylose. In four strains isolated from two independent evolution experiments the galactose-transporter gene GAL2 had been duplicated, with all alleles encoding Gal2N376T or Gal2N376I substitutions. In one strain, a single GAL2 allele additionally encoded a Gal2T89I substitution, which was subsequently also detected in the independently evolved strain IMS0010. In 14C-sugar-transport assays, Gal2N376S, Gal2N376T and Gal2N376I substitutions showed a much lower glucose sensitivity of l-arabinose transport and a much higher Km for d-glucose transport than wild-type Gal2. Introduction of the Gal2N376I substitution in a non-evolved strain enabled growth on l-arabinose in the presence of d-glucose. Gal2N376T, T89I and Gal2T89I variants showed a lower Km for l-arabinose and a higher Km for d-glucose than wild-type Gal2, while reverting Gal2N376T, T89I to Gal2N376 in an evolved strain negatively affected anaerobic growth on l-arabinose. This study indicates that optimal conversion of mixed-sugar feedstocks may require complex ‘transporter landscapes’, consisting of sugar transporters with complementary kinetic and regulatory properties.
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Affiliation(s)
- Maarten D Verhoeven
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Jasmine M Bracher
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Jeroen G Nijland
- Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Jonna Bouwknegt
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Jean-Marc G Daran
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Arnold J M Driessen
- Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Antonius J A van Maris
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Jack T Pronk
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
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9
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The production of ethanol from lignocellulosic biomass by Kluyveromyces marxianus CICC 1727-5 and Spathaspora passalidarum ATCC MYA-4345. Appl Microbiol Biotechnol 2019; 103:2845-2855. [DOI: 10.1007/s00253-019-09625-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Revised: 11/18/2018] [Accepted: 12/16/2018] [Indexed: 11/25/2022]
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10
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Gao M, Ploessl D, Shao Z. Enhancing the Co-utilization of Biomass-Derived Mixed Sugars by Yeasts. Front Microbiol 2019; 9:3264. [PMID: 30723464 PMCID: PMC6349770 DOI: 10.3389/fmicb.2018.03264] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 12/14/2018] [Indexed: 12/11/2022] Open
Abstract
Plant biomass is a promising carbon source for producing value-added chemicals, including transportation biofuels, polymer precursors, and various additives. Most engineered microbial hosts and a select group of wild-type species can metabolize mixed sugars including oligosaccharides, hexoses, and pentoses that are hydrolyzed from plant biomass. However, most of these microorganisms consume glucose preferentially to non-glucose sugars through mechanisms generally defined as carbon catabolite repression. The current lack of simultaneous mixed-sugar utilization limits achievable titers, yields, and productivities. Therefore, the development of microbial platforms capable of fermenting mixed sugars simultaneously from biomass hydrolysates is essential for economical industry-scale production, particularly for compounds with marginal profits. This review aims to summarize recent discoveries and breakthroughs in the engineering of yeast cell factories for improved mixed-sugar co-utilization based on various metabolic engineering approaches. Emphasis is placed on enhanced non-glucose utilization, discovery of novel sugar transporters free from glucose repression, native xylose-utilizing microbes, consolidated bioprocessing (CBP), improved cellulase secretion, and creation of microbial consortia for improving mixed-sugar utilization. Perspectives on the future development of biorenewables industry are provided in the end.
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Affiliation(s)
- Meirong Gao
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, United States.,NSF Engineering Research Center for Biorenewable Chemicals (CBiRC), Iowa State University, Ames, IA, United States
| | - Deon Ploessl
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, United States.,NSF Engineering Research Center for Biorenewable Chemicals (CBiRC), Iowa State University, Ames, IA, United States
| | - Zengyi Shao
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, United States.,NSF Engineering Research Center for Biorenewable Chemicals (CBiRC), Iowa State University, Ames, IA, United States.,The Ames Laboratory, Iowa State University, Ames, IA, United States.,The Interdisciplinary Microbiology Program, Biorenewables Research Laboratory, Iowa State University, Ames, IA, United States
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11
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Oehling V, Klaassen P, Frick O, Dusny C, Schmid A. l-Arabinose triggers its own uptake via induction of the arabinose-specific Gal2p transporter in an industrial Saccharomyces cerevisiae strain. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:231. [PMID: 30159031 PMCID: PMC6106821 DOI: 10.1186/s13068-018-1231-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 08/17/2018] [Indexed: 06/08/2023]
Abstract
Bioethanol production processes with Saccharomyces cerevisiae using lignocellulosic biomass as feedstock are challenged by the simultaneous utilization of pentose and hexose sugars from biomass hydrolysates. The pentose uptake into the cell represents a crucial role for the efficiency of the process. The focus of the here presented study was to understand the uptake and conversion of the pentose l-arabinose in S. cerevisiae and reveal its regulation by d-glucose and d-galactose. Gal2p-the most prominent transporter enabling l-arabinose uptake in S. cerevisiae wild-type strains-has an affinity for the transport of l-arabinose, d-glucose, and d-galactose. d-Galactose was reported for being mandatory for inducing GAL2 expression. GAL2 expression is also known to be regulated by d-glucose-mediated carbon catabolite repression, as well as catabolite inactivation. The results of the present study demonstrate that l-arabinose can be used as sole carbon and energy source by the recombinant industrial strain S. cerevisiae DS61180. RT-qPCR and RNA-Seq experiments confirmed that l-arabinose can trigger its own uptake via the induction of GAL2 expression. Expression levels of GAL2 during growth on l-arabinose reached up to 21% of those obtained with d-galactose as sole carbon and energy source. l-Arabinose-induced GAL2 expression was also subject to catabolite repression by d-glucose. Kinetic investigations of substrate uptake, biomass, and product formation during growth on a mixture of d-glucose/l-arabinose revealed impairment of growth and ethanol production from l-arabinose upon d-glucose depletion. The presence of d-glucose is thus preventing the fermentation of l-arabinose in S. cerevisiae DS61180. Comparative transcriptome studies including the wild-type and a precursor strain delivered hints for an increased demand in ATP production and cofactor regeneration during growth of S. cerevisiae DS61180 on l-arabinose. Our results thus emphasize that cofactor and energy metabolism demand attention if the combined conversion of hexose and pentose sugars is intended, for example in biorefineries using lignocellulosics.
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Affiliation(s)
- Verena Oehling
- Laboratory of Chemical Biotechnology, Department of Biochemical & Chemical Engineering, TU Dortmund University, Dortmund, Germany
| | | | - Oliver Frick
- Laboratory of Chemical Biotechnology, Department of Biochemical & Chemical Engineering, TU Dortmund University, Dortmund, Germany
- Present Address: Department of Solar Materials, Helmholtz Centre for Environmental Research UFZ, Leipzig, Germany
| | - Christian Dusny
- Laboratory of Chemical Biotechnology, Department of Biochemical & Chemical Engineering, TU Dortmund University, Dortmund, Germany
- Present Address: Department of Solar Materials, Helmholtz Centre for Environmental Research UFZ, Leipzig, Germany
| | - Andreas Schmid
- Laboratory of Chemical Biotechnology, Department of Biochemical & Chemical Engineering, TU Dortmund University, Dortmund, Germany
- Present Address: Department of Solar Materials, Helmholtz Centre for Environmental Research UFZ, Leipzig, Germany
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12
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Wang C, Li Y, Qiu C, Wang S, Ma J, Shen Y, Zhang Q, Du B, Ding Y, Bao X. Identification of Important Amino Acids in Gal2p for Improving the L-arabinose Transport and Metabolism in Saccharomyces cerevisiae. Front Microbiol 2017; 8:1391. [PMID: 28785254 PMCID: PMC5519586 DOI: 10.3389/fmicb.2017.01391] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 07/10/2017] [Indexed: 11/29/2022] Open
Abstract
Efficient and cost-effective bioethanol production from lignocellulosic materials requires co-fermentation of the main hydrolyzed sugars, including glucose, xylose, and L-arabinose. Saccharomyces cerevisiae is a glucose-fermenting yeast that is traditionally used for ethanol production. Fermentation of L-arabinose is also possible after metabolic engineering. Transport into the cell is the first and rate-limiting step for L-arabinose metabolism. The galactose permease, Gal2p, is a non-specific, endogenous monosaccharide transporter that has been shown to transport L-arabinose. However, Gal2p-mediated transport of L-arabinose occurs at a low efficiency. In this study, homologous modeling and L-arabinose docking were used to predict amino acids in Gal2p that are crucial for L-arabinose transport. Nine amino acid residues in Gal2p were identified and were the focus for site-directed mutagenesis. In the Gal2p transport-deficient chassis cells, the capacity for L-arabinose transport of the different Gal2p mutants was compared by testing growth rates using L-arabinose as the sole carbon source. Almost all the tested mutations affected L-arabinose transport capacity. Among them, F85 is a unique site. The F85S, F85G, F85C, and F85T point mutations significantly increased L-arabinose transport activities, while, the F85E and F85R mutations decreased L-arabinose transport activities compared to the Gal2p-expressing wild-type strain. These results verified F85 as a key residue in L-arabinose transport. The F85S mutation, having the most significant effect, elevated the exponential growth rate by 40%. The F85S mutation also improved xylose transport efficiency and weakened the glucose transport preference. Overall, enhancing the L-arabinose transport capacity further improved the L-arabinose metabolism of engineered S. cerevisiae.
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Affiliation(s)
- Chengqiang Wang
- College of Life Sciences/Shandong Key Laboratory of Agricultural Microbiology, Shandong Agricultural UniversityTai'an, China.,The State Key Laboratory of Microbial Technology/Environment Research Institute, Shandong UniversityJinan, China
| | - Yanwei Li
- The State Key Laboratory of Microbial Technology/Environment Research Institute, Shandong UniversityJinan, China
| | - Chenxi Qiu
- College of Life Sciences/Shandong Key Laboratory of Agricultural Microbiology, Shandong Agricultural UniversityTai'an, China.,The State Key Laboratory of Microbial Technology/Environment Research Institute, Shandong UniversityJinan, China
| | - Shihao Wang
- College of Life Sciences/Shandong Key Laboratory of Agricultural Microbiology, Shandong Agricultural UniversityTai'an, China.,The State Key Laboratory of Microbial Technology/Environment Research Institute, Shandong UniversityJinan, China
| | - Jinjin Ma
- College of Life Sciences/Shandong Key Laboratory of Agricultural Microbiology, Shandong Agricultural UniversityTai'an, China
| | - Yu Shen
- The State Key Laboratory of Microbial Technology/Environment Research Institute, Shandong UniversityJinan, China
| | - Qingzhu Zhang
- The State Key Laboratory of Microbial Technology/Environment Research Institute, Shandong UniversityJinan, China
| | - Binghai Du
- College of Life Sciences/Shandong Key Laboratory of Agricultural Microbiology, Shandong Agricultural UniversityTai'an, China
| | - Yanqin Ding
- College of Life Sciences/Shandong Key Laboratory of Agricultural Microbiology, Shandong Agricultural UniversityTai'an, China
| | - Xiaoming Bao
- The State Key Laboratory of Microbial Technology/Environment Research Institute, Shandong UniversityJinan, China.,College of Bioengineering, Qilu University of TechnologyJinan, China
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13
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Caballero A, Ramos JL. Enhancing ethanol yields through d-xylose and l-arabinose co-fermentation after construction of a novel high efficient l-arabinose-fermenting Saccharomyces cerevisiae strain. Microbiology (Reading) 2017; 163:442-452. [DOI: 10.1099/mic.0.000437] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Antonio Caballero
- Abengoa Research, Department of Biotechnology, Campus de Palmas Altas, c/Energia Solar number 1, 41004 Sevilla, Spain
- BacMine, C/de Santiago Grisolía 28760 Tres Cantos, Spain
| | - Juan Luis Ramos
- Abengoa Research, Department of Biotechnology, Campus de Palmas Altas, c/Energia Solar number 1, 41004 Sevilla, Spain
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14
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Coutilization of D-Glucose, D-Xylose, and L-Arabinose in Saccharomyces cerevisiae by Coexpressing the Metabolic Pathways and Evolutionary Engineering. BIOMED RESEARCH INTERNATIONAL 2017; 2017:5318232. [PMID: 28459063 PMCID: PMC5385224 DOI: 10.1155/2017/5318232] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 03/04/2017] [Accepted: 03/20/2017] [Indexed: 11/23/2022]
Abstract
Efficient and cost-effective fuel ethanol production from lignocellulosic materials requires simultaneous cofermentation of all hydrolyzed sugars, mainly including D-glucose, D-xylose, and L-arabinose. Saccharomyces cerevisiae is a traditional D-glucose fermenting strain and could utilize D-xylose and L-arabinose after introducing the initial metabolic pathways. The efficiency and simultaneous coutilization of the two pentoses and D-glucose for ethanol production in S. cerevisiae still need to be optimized. Previously, we constructed an L-arabinose-utilizing S. cerevisiae BSW3AP. In this study, we further introduced the XI and XR-XDH metabolic pathways of D-xylose into BSW3AP to obtain D-glucose, D-xylose, and L-arabinose cofermenting strain. Benefits of evolutionary engineering: the resulting strain BSW4XA3 displayed a simultaneous coutilization of D-xylose and L-arabinose with similar consumption rates, and the D-glucose metabolic capacity was not decreased. After 120 h of fermentation on mixed D-glucose, D-xylose, and L-arabinose, BSW4XA3 consumed 24% more amounts of pentoses and the ethanol yield of mixed sugars was increased by 30% than that of BSW3AP. The resulting strain BSW4XA3 was a useful chassis for further enhancing the coutilization efficiency of mixed sugars for bioethanol production.
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15
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Tang H, Song M, He Y, Wang J, Wang S, Shen Y, Hou J, Bao X. Engineering vesicle trafficking improves the extracellular activity and surface display efficiency of cellulases in Saccharomyces cerevisiae. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:53. [PMID: 28261326 PMCID: PMC5327580 DOI: 10.1186/s13068-017-0738-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 02/17/2017] [Indexed: 05/12/2023]
Abstract
BACKGROUND Cellulase expression via extracellular secretion or surface display in Saccharomyces cerevisiae is one of the most frequently used strategies for a consolidated bioprocess (CBP) of cellulosic ethanol production. However, the inefficiency of the yeast secretory pathway often results in low production of heterologous proteins, which largely limits cellulase secretion or display. RESULTS In this study, the components of the vesicle trafficking from the endoplasmic reticulum (ER) to the Golgi and from the Golgi to the plasma membrane, involved in vesicle budding, tethering and fusion, were over-expressed in Clostridium thermocellum endoglucanase (CelA)- and Sacchromycopsis fibuligera β-glucosidase (BGL1)-secreting or -displaying strains. Engineering the targeted components in the ER to Golgi vesicle trafficking, including Sec12p, Sec13p, Erv25p and Bos1p, enhanced the extracellular activity of CelA. However, only Sec13p over-expression increased BGL1 secretion. By contrast, over-expression of the components in the Golgi to plasma membrane vesicle trafficking, including Sso1p, Snc2p, Sec1p, Exo70p, Ypt32p and Sec4p, showed better performance in increasing BGL1 secretion compared to CelA secretion, and the over-expression of these components all increased BGL1 extracellular activity. These results revealed that various cellulases showed different limitations in protein transport, and engineering vesicle trafficking has protein-specific effects. Importantly, we found that engineering the above vesicle trafficking components, particularly from the ER to the Golgi, also improved the display efficiency of CelA and BGL1 when a-agglutinin was used as surface display system. Further analyses illustrated that the display efficiency of a-agglutinin was increased by engineering vesicle trafficking, and the trend was consistent with displayed CelA and BGL1. These results indicated that fusion with a-agglutinin may affect the proteins' properties and alter the rate-limiting step in the vesicle trafficking. CONCLUSIONS We have demonstrated, for the first time, engineering vesicle trafficking from the ER to the Golgi and from the Golgi to the plasma membrane can enhance the protein display efficiency. We also found that different heterologous proteins had specific limitations in vesicle trafficking pathway and that engineering the vesicle trafficking resulted in a protein-specific effect. These results provide a new strategy to improve the extracellular secretion and surface display of cellulases in S. cerevisiae.
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Affiliation(s)
- Hongting Tang
- The School of Life Science, State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100 China
| | - Meihui Song
- The School of Life Science, State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100 China
| | - Yao He
- The School of Life Science, State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100 China
| | - Jiajing Wang
- The School of Life Science, State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100 China
| | - Shenghuan Wang
- The School of Life Science, State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100 China
| | - Yu Shen
- The School of Life Science, State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100 China
| | - Jin Hou
- The School of Life Science, State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100 China
| | - Xiaoming Bao
- The School of Life Science, State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100 China
- Shandong Provincial Key Laboratory of Microbial Engineering, Qi Lu University of Technology, Jinan, 250353 China
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16
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Tang H, Wang S, Wang J, Song M, Xu M, Zhang M, Shen Y, Hou J, Bao X. N-hypermannose glycosylation disruption enhances recombinant protein production by regulating secretory pathway and cell wall integrity in Saccharomyces cerevisiae. Sci Rep 2016; 6:25654. [PMID: 27156860 PMCID: PMC4860636 DOI: 10.1038/srep25654] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 04/14/2016] [Indexed: 12/30/2022] Open
Abstract
Saccharomyces cerevisiae is a robust host for heterologous protein expression. The efficient expression of cellulases in S. cerevisiae is important for the consolidated bioprocess that directly converts lignocellulose into valuable products. However, heterologous proteins are often N-hyperglycosylated in S. cerevisiae, which may affect protein activity. In this study, the expression of three heterologous proteins, β-glucosidase, endoglucanase and cellobiohydrolase, was found to be N-hyperglycosylated in S. cerevisiae. To block the formation of hypermannose glycan, these proteins were expressed in strains with deletions in key Golgi mannosyltransferases (Och1p, Mnn9p and Mnn1p), respectively. Their extracellular activities improved markedly in the OCH1 and MNN9 deletion strains. Interestingly, truncation of the N-hypermannose glycan did not increase the specific activity of these proteins, but improved the secretion yield. Further analysis showed OCH1 and MNN9 deletion up-regulated genes in the secretory pathway, such as protein folding and vesicular trafficking, but did not induce the unfolded protein response. The cell wall integrity was also affected by OCH1 and MNN9 deletion, which contributed to the release of secretory protein extracellularly. This study demonstrated that mannosyltransferases disruption improved protein secretion through up-regulating secretory pathway and affecting cell wall integrity and provided new insights into glycosylation engineering for protein secretion.
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Affiliation(s)
- Hongting Tang
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100, China
| | - Shenghuan Wang
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100, China
| | - Jiajing Wang
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100, China
| | - Meihui Song
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100, China
| | - Mengyang Xu
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100, China
| | - Mengying Zhang
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100, China
| | - Yu Shen
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100, China
| | - Jin Hou
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100, China
| | - Xiaoming Bao
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100, China
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17
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Knoshaug EP, Vidgren V, Magalhães F, Jarvis EE, Franden MA, Zhang M, Singh A. Novel transporters from
Kluyveromyces marxianus
and
Pichia guilliermondii
expressed in
Saccharomyces cerevisiae
enable growth on
l
‐arabinose and
d
‐xylose. Yeast 2015; 32:615-28. [DOI: 10.1002/yea.3084] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Revised: 05/11/2015] [Accepted: 06/23/2015] [Indexed: 11/08/2022] Open
Affiliation(s)
- Eric P. Knoshaug
- National Renewable Energy Laboratory National Bioenergy Centre Golden CO USA
| | - Virve Vidgren
- VTT Technical Research Centre of Finland PO Box 1000 FI‐02044 VTT Finland
| | | | - Eric E. Jarvis
- National Renewable Energy Laboratory National Bioenergy Centre Golden CO USA
| | - Mary Ann Franden
- National Renewable Energy Laboratory National Bioenergy Centre Golden CO USA
| | - Min Zhang
- National Renewable Energy Laboratory National Bioenergy Centre Golden CO USA
| | - Arjun Singh
- National Renewable Energy Laboratory National Bioenergy Centre Golden CO USA
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18
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Wang C, Bao X, Li Y, Jiao C, Hou J, Zhang Q, Zhang W, Liu W, Shen Y. Cloning and characterization of heterologous transporters in Saccharomyces cerevisiae and identification of important amino acids for xylose utilization. Metab Eng 2015; 30:79-88. [DOI: 10.1016/j.ymben.2015.04.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 03/25/2015] [Accepted: 04/24/2015] [Indexed: 12/31/2022]
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19
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Tang H, Bao X, Shen Y, Song M, Wang S, Wang C, Hou J. Engineering protein folding and translocation improves heterologous protein secretion inSaccharomyces cerevisiae. Biotechnol Bioeng 2015; 112:1872-82. [DOI: 10.1002/bit.25596] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 03/11/2015] [Accepted: 03/16/2015] [Indexed: 11/10/2022]
Affiliation(s)
- Hongting Tang
- State Key Laboratory of Microbial Technology; Shandong University; Jinan 250100 China
| | - Xiaoming Bao
- State Key Laboratory of Microbial Technology; Shandong University; Jinan 250100 China
| | - Yu Shen
- State Key Laboratory of Microbial Technology; Shandong University; Jinan 250100 China
| | - Meihui Song
- State Key Laboratory of Microbial Technology; Shandong University; Jinan 250100 China
| | - Shenghuan Wang
- State Key Laboratory of Microbial Technology; Shandong University; Jinan 250100 China
| | - Chengqiang Wang
- State Key Laboratory of Microbial Technology; Shandong University; Jinan 250100 China
| | - Jin Hou
- State Key Laboratory of Microbial Technology; Shandong University; Jinan 250100 China
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20
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Wang C, Bao X, Li Y, Jiao C, Hou J, Zhang Q, Zhang W, Liu W, Shen Y. Data set for cloning and characterization of heterologous transporters in Saccharomyces cerevisiae and identification of important amino acids for xylose utilization. Data Brief 2015. [PMID: 26217774 PMCID: PMC4510445 DOI: 10.1016/j.dib.2015.05.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The efficient uptake is important for the xylose utilization by Saccharomyces cerevisiae. A heterogenous transporter Mgt05196p was cloned from Meyerozyma guilliermondii and expressed in Saccharomyces cerevisiae[1]. This data article contains the transport characteristics of Mgt05196p in S. cerevisiae. The fluorescence of fusion protein Mgt05196p-GFP expressing strain was located on the cell surface demonstrated that the heterogenous transporter Mgt05196p was targeted to the plasma membrane of S. cerevisiae. The expressing of Mgt05196p in the hxt null S. cerevisiae endowed the strain with the glucose and d-xylose absorption capacity, as well as expressing the native d-xylose transporter Gal2p. The transmembrane domains of Mgt05196p were predicted and compared with the XylEp, whose crystal structure was revealed. And then, the homologous modeling of Mgt05196p was built basing on the XylEp to find out the crucial amino acid residues for sugars binding and transport.
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Affiliation(s)
- Chengqiang Wang
- The State Key Laboratory of Microbial Technology, Shandong University, Shan Da Nan Road27, Jinan 250100, PR China ; College of Life Sciences, Shandong Agricultural University/Shandong Key Laboratory of Agricultural Microbiology, Daizong Street 61, Taian 271018, PR China
| | - Xiaoming Bao
- The State Key Laboratory of Microbial Technology, Shandong University, Shan Da Nan Road27, Jinan 250100, PR China
| | - Yanwei Li
- Environment Research Institute, Shandong University, Shan Da Nan Road 27, Jinan 250100, PR China
| | - Chunlei Jiao
- The State Key Laboratory of Microbial Technology, Shandong University, Shan Da Nan Road27, Jinan 250100, PR China
| | - Jin Hou
- The State Key Laboratory of Microbial Technology, Shandong University, Shan Da Nan Road27, Jinan 250100, PR China
| | - Qingzhu Zhang
- Environment Research Institute, Shandong University, Shan Da Nan Road 27, Jinan 250100, PR China
| | - Weixin Zhang
- The State Key Laboratory of Microbial Technology, Shandong University, Shan Da Nan Road27, Jinan 250100, PR China
| | - Weifeng Liu
- The State Key Laboratory of Microbial Technology, Shandong University, Shan Da Nan Road27, Jinan 250100, PR China
| | - Yu Shen
- The State Key Laboratory of Microbial Technology, Shandong University, Shan Da Nan Road27, Jinan 250100, PR China
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21
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Functional Analysis of Two l-Arabinose Transporters from Filamentous Fungi Reveals Promising Characteristics for Improved Pentose Utilization in Saccharomyces cerevisiae. Appl Environ Microbiol 2015; 81:4062-70. [PMID: 25841015 DOI: 10.1128/aem.00165-15] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 03/31/2015] [Indexed: 11/20/2022] Open
Abstract
Limited uptake is one of the bottlenecks for l-arabinose fermentation from lignocellulosic hydrolysates in engineered Saccharomyces cerevisiae. This study characterized two novel l-arabinose transporters, LAT-1 from Neurospora crassa and MtLAT-1 from Myceliophthora thermophila. Although the two proteins share high identity (about 83%), they display different substrate specificities. Sugar transport assays using the S. cerevisiae strain EBY.VW4000 indicated that LAT-1 accepts a broad substrate spectrum. In contrast, MtLAT-1 appeared much more specific for l-arabinose. Determination of the kinetic properties of both transporters revealed that the Km values of LAT-1 and MtLAT-1 for l-arabinose were 58.12 ± 4.06 mM and 29.39 ± 3.60 mM, respectively, with corresponding Vmax values of 116.7 ± 3.0 mmol/h/g dry cell weight (DCW) and 10.29 ± 0.35 mmol/h/g DCW, respectively. In addition, both transporters were found to use a proton-coupled symport mechanism and showed only partial inhibition by d-glucose during l-arabinose uptake. Moreover, LAT-1 and MtLAT-1 were expressed in the S. cerevisiae strain BSW2AP containing an l-arabinose metabolic pathway. Both recombinant strains exhibited much faster l-arabinose utilization, greater biomass accumulation, and higher ethanol production than the control strain. In conclusion, because of higher maximum velocities and reduced inhibition by d-glucose, the genes for the two characterized transporters are promising targets for improved l-arabinose utilization and fermentation in S. cerevisiae.
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22
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Challenges for the production of bioethanol from biomass using recombinant yeasts. ADVANCES IN APPLIED MICROBIOLOGY 2015; 92:89-125. [PMID: 26003934 DOI: 10.1016/bs.aambs.2015.02.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Lignocellulose biomass, one of the most abundant renewable resources on the planet, is an alternative sustainable energy source for the production of second-generation biofuels. Energy in the form of simple or complex carbohydrates can be extracted from lignocellulose biomass and fermented by microorganisms to produce bioethanol. Despite 40 years of active and cutting-edge research invested into the development of technologies to produce bioethanol from lignocellulosic biomass, the process remains commercially unviable. This review describes the achievements that have been made in generating microorganisms capable of utilizing both simple and complex sugars from lignocellulose biomass and the fermentation of these sugars into ethanol. We also provide a discussion on the current "roadblocks" standing in the way of making second-generation bioethanol a commercially viable alternative to fossil fuels.
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23
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Li H, Wu M, Xu L, Hou J, Guo T, Bao X, Shen Y. Evaluation of industrial Saccharomyces cerevisiae strains as the chassis cell for second-generation bioethanol production. Microb Biotechnol 2015; 8:266-74. [PMID: 25616171 PMCID: PMC4353340 DOI: 10.1111/1751-7915.12245] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 10/13/2014] [Accepted: 10/22/2014] [Indexed: 11/26/2022] Open
Abstract
To develop a suitable Saccharomyces cerevisiae industrial strain as a chassis cell for ethanol production using lignocellulosic materials, 32 wild-type strains were evaluated for their glucose fermenting ability, their tolerance to the stresses they might encounter in lignocellulosic hydrolysate fermentation and their genetic background for pentose metabolism. The strain BSIF, isolated from tropical fruit in Thailand, was selected out of the distinctly different strains studied for its promising characteristics. The maximal specific growth rate of BSIF was as high as 0.65 h(-1) in yeast extract peptone dextrose medium, and the ethanol yield was 0.45 g g(-1) consumed glucose. Furthermore, compared with other strains, this strain exhibited superior tolerance to high temperature, hyperosmotic stress and oxidative stress; better growth performance in lignocellulosic hydrolysate; and better xylose utilization capacity when an initial xylose metabolic pathway was introduced. All of these results indicate that this strain is an excellent chassis strain for lignocellulosic ethanol production.
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Affiliation(s)
- Hongxing Li
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100, China
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24
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Wimalasena TT, Greetham D, Marvin ME, Liti G, Chandelia Y, Hart A, Louis EJ, Phister TG, Tucker GA, Smart KA. Phenotypic characterisation of Saccharomyces spp. yeast for tolerance to stresses encountered during fermentation of lignocellulosic residues to produce bioethanol. Microb Cell Fact 2014; 13:47. [PMID: 24670111 PMCID: PMC3986927 DOI: 10.1186/1475-2859-13-47] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 03/19/2014] [Indexed: 12/02/2022] Open
Abstract
Background During industrial fermentation of lignocellulose residues to produce bioethanol, microorganisms are exposed to a number of factors that influence productivity. These include inhibitory compounds produced by the pre-treatment processes required to release constituent carbohydrates from biomass feed-stocks and during fermentation, exposure of the organisms to stressful conditions. In addition, for lignocellulosic bioethanol production, conversion of both pentose and hexose sugars is a pre-requisite for fermentative organisms for efficient and complete conversion. All these factors are important to maximise industrial efficiency, productivity and profit margins in order to make second-generation bioethanol an economically viable alternative to fossil fuels for future transport needs. Results The aim of the current study was to assess Saccharomyces yeasts for their capacity to tolerate osmotic, temperature and ethanol stresses and inhibitors that might typically be released during steam explosion of wheat straw. Phenotypic microarray analysis was used to measure tolerance as a function of growth and metabolic activity. Saccharomyces strains analysed in this study displayed natural variation to each stress condition common in bioethanol fermentations. In addition, many strains displayed tolerance to more than one stress, such as inhibitor tolerance combined with fermentation stresses. Conclusions Our results suggest that this study could identify a potential candidate strain or strains for efficient second generation bioethanol production. Knowledge of the Saccharomyces spp. strains grown in these conditions will aid the development of breeding programmes in order to generate more efficient strains for industrial fermentations.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Katherine A Smart
- Bioenergy & Brewing Science, School of Biosciences, Sutton Bonington Campus, University of Nottingham, Loughborough, Leicestershire LE12 6RD, UK.
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25
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Hou J, Suo F, Wang C, Li X, Shen Y, Bao X. Fine-tuning of NADH oxidase decreases byproduct accumulation in respiration deficient xylose metabolic Saccharomyces cerevisiae. BMC Biotechnol 2014; 14:13. [PMID: 24529074 PMCID: PMC3928090 DOI: 10.1186/1472-6750-14-13] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 02/08/2014] [Indexed: 01/01/2023] Open
Abstract
Background Efficiently utilizing all available carbon from lignocellulosic feedstock presents a major barrier to the production of economically feasible biofuel. Previously, to enable xylose utilization, we introduced a cofactor-dependent xylose reductase (XR) and xylitol dehydrogenase (XDH) pathway, or a cofactor-independent xylose isomerase (XI) pathway, into Saccharomyces cerevisiae. The resulting strains metabolized xylose with high efficiency. However, in both pathway recombinant strains, the cofactor imbalance caused accumulation of the byproducts glycerol and/or xylitol and reduced the ethanol production efficiency. Results In this study, we introduced NADH oxidase from Lactococcus lactis into both XI and XR-XDH pathway recombinant strains. To reduce byproduct accumulation while maintaining xylose metabolism, we optimized the expression level of NADH oxidase by comparing its expression under the control of different promoters and plasmids. In recombinant XI strains, NADH oxidase was expressed at different levels, regulated by the GPD2 promoter or TEF1 promoter in the 2 μ plasmid. The expression under the control of GPD2 promoter decreased glycerol production by 84% and increased the ethanol yield and specific growth rate by 8% and 12%, respectively. In contrast, in the recombinant XR-XDH strains, such expression level was not efficient enough to decrease the byproduct accumulation. Therefore, higher NADH oxidase expression levels were tested. In the strain expressing NADH oxidase under the control of the TEF1 promoter in the centromeric plasmids, xylitol and glycerol production were reduced by 60% and 83%, respectively, without significantly affecting xylose consumption. Conclusions By fine-tuning NADH oxidase expression, we decreased the glycerol or/and xylitol production in both recombinant XI and XR-XDH xylose-metabolizing yeast strains. The optimal NADH oxidase expression levels depend on metabolic pathways. Similar cofactor engineering strategies could maximize the production of other redox dependent metabolites.
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Affiliation(s)
| | | | | | | | | | - Xiaoming Bao
- State Key Laboratory of Microbial Technology, Shandong University, Shanda Nan Road 27, Jinan 250100, China.
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