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Genomewide and Enzymatic Analysis Reveals Efficient d-Galacturonic Acid Metabolism in the Basidiomycete Yeast Rhodosporidium toruloides. mSystems 2019; 4:4/6/e00389-19. [PMID: 31848309 PMCID: PMC6918025 DOI: 10.1128/msystems.00389-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Biorefining of renewable feedstocks is one of the most promising routes to replace fossil-based products. Since many common fermentation hosts, such as Saccharomyces cerevisiae, are naturally unable to convert many component plant cell wall polysaccharides, the identification of organisms with broad catabolism capabilities represents an opportunity to expand the range of substrates used in fermentation biorefinery approaches. The red basidiomycete yeast Rhodosporidium toruloides is a promising and robust host for lipid- and terpene-derived chemicals. Previous studies demonstrated assimilation of a range of substrates, from C5/C6 sugars to aromatic molecules similar to lignin monomers. In the current study, we analyzed the potential of R. toruloides to assimilate d-galacturonic acid, a major sugar in many pectin-rich agricultural waste streams, including sugar beet pulp and citrus peels. d-Galacturonic acid is not a preferred substrate for many fungi, but its metabolism was found to be on par with those of d-glucose and d-xylose in R. toruloides A genomewide analysis by combined transcriptome sequencing (RNA-seq) and RB-TDNA-seq revealed those genes with high relevance for fitness on d-galacturonic acid. While R. toruloides was found to utilize the nonphosphorylative catabolic pathway known from ascomycetes, the maximal velocities of several enzymes exceeded those previously reported. In addition, an efficient downstream glycerol catabolism and a novel transcription factor were found to be important for d-galacturonic acid utilization. These results set the basis for use of R. toruloides as a potential host for pectin-rich waste conversions and demonstrate its suitability as a model for metabolic studies with basidiomycetes.IMPORTANCE The switch from the traditional fossil-based industry to a green and sustainable bioeconomy demands the complete utilization of renewable feedstocks. Many currently used bioconversion hosts are unable to utilize major components of plant biomass, warranting the identification of microorganisms with broader catabolic capacity and characterization of their unique biochemical pathways. d-Galacturonic acid is a plant component of bioconversion interest and is the major backbone sugar of pectin, a plant cell wall polysaccharide abundant in soft and young plant tissues. The red basidiomycete and oleaginous yeast Rhodosporidium toruloides has been previously shown to utilize a range of sugars and aromatic molecules. Using state-of-the-art functional genomic methods and physiological and biochemical assays, we elucidated the molecular basis underlying the efficient metabolism of d-galacturonic acid. This study identified an efficient pathway for uronic acid conversion to guide future engineering efforts and represents the first detailed metabolic analysis of pectin metabolism in a basidiomycete fungus.
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Bioprospection of Enzymes and Microorganisms in Insects to Improve Second-Generation Ethanol Production. Ind Biotechnol (New Rochelle N Y) 2019. [DOI: 10.1089/ind.2019.0019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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Smekenov I, Bakhtambayeva M, Bissenbayev K, Saparbayev M, Taipakova S, Bissenbaev AK. Heterologous secretory expression of β-glucosidase from Thermoascus aurantiacus in industrial Saccharomyces cerevisiae strains. Braz J Microbiol 2019; 51:107-123. [PMID: 31776864 DOI: 10.1007/s42770-019-00192-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 11/14/2019] [Indexed: 10/25/2022] Open
Abstract
The use of plant biomass for biofuel production will require efficient utilization of the sugars in lignocellulose, primarily cellobiose, because it is the major soluble by-product of cellulose and acts as a strong inhibitor, especially for cellobiohydrolase, which plays a key role in cellulose hydrolysis. Commonly used ethanologenic yeast Saccharomyces cerevisiae is unable to utilize cellobiose; accordingly, genetic engineering efforts have been made to transfer β-glucosidase genes enabling cellobiose utilization. Nonetheless, laboratory yeast strains have been employed for most of this research, and such strains may be difficult to use in industrial processes because of their generally weaker resistance to stressors and worse fermenting abilities. The purpose of this study was to engineer industrial yeast strains to ferment cellobiose after stable integration of tabgl1 gene that encodes a β-glucosidase from Thermoascus aurantiacus (TaBgl1). The recombinant S. cerevisiae strains obtained in this study secrete TaBgl1, which can hydrolyze cellobiose and produce ethanol. This study clearly indicates that the extent of glycosylation of secreted TaBgl1 depends from the yeast strains used and is greatly influenced by carbon sources (cellobiose or glucose). The recombinant yeast strains showed high osmotolerance and resistance to various concentrations of ethanol and furfural and to high temperatures. Therefore, these yeast strains are suitable for ethanol production processes with saccharified lignocellulose.
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Affiliation(s)
- Izat Smekenov
- Department of Molecular Biology and Genetics, Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan, 050040.,Scientific Research Institute of Biology and Biotechnology Problems, Al-Farabi Kazakh National University, Almaty, Kazakhstan, 050040
| | - Marzhan Bakhtambayeva
- Department of Molecular Biology and Genetics, Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan, 050040.,Scientific Research Institute of Biology and Biotechnology Problems, Al-Farabi Kazakh National University, Almaty, Kazakhstan, 050040
| | - Kudaybergen Bissenbayev
- Scientific Research Institute of Biology and Biotechnology Problems, Al-Farabi Kazakh National University, Almaty, Kazakhstan, 050040.,Nazarbayev Intellectual School, Almaty, Kazakhstan, 050044
| | - Murat Saparbayev
- Gustave Roussy Cancer Campus, CNRS UMR8200, Université Paris-Sud, F-94805, Villejuif Cedex, France
| | - Sabira Taipakova
- Department of Molecular Biology and Genetics, Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan, 050040.,Scientific Research Institute of Biology and Biotechnology Problems, Al-Farabi Kazakh National University, Almaty, Kazakhstan, 050040
| | - Amangeldy K Bissenbaev
- Department of Molecular Biology and Genetics, Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan, 050040. .,Scientific Research Institute of Biology and Biotechnology Problems, Al-Farabi Kazakh National University, Almaty, Kazakhstan, 050040.
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Lin L, Wang S, Li X, He Q, Benz JP, Tian C. STK-12 acts as a transcriptional brake to control the expression of cellulase-encoding genes in Neurospora crassa. PLoS Genet 2019; 15:e1008510. [PMID: 31765390 PMCID: PMC6901240 DOI: 10.1371/journal.pgen.1008510] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 12/09/2019] [Accepted: 11/05/2019] [Indexed: 12/21/2022] Open
Abstract
Cellulolytic fungi have evolved a complex regulatory network to maintain the precise balance of nutrients required for growth and hydrolytic enzyme production. When fungi are exposed to cellulose, the transcript levels of cellulase genes rapidly increase and then decline. However, the mechanisms underlying this bell-shaped expression pattern are unclear. We systematically screened a protein kinase deletion set in the filamentous fungus Neurospora crassa to search for mutants exhibiting aberrant expression patterns of cellulase genes. We observed that the loss of stk-12 (NCU07378) caused a dramatic increase in cellulase production and an extended period of high transcript abundance of major cellulase genes. These results suggested that stk-12 plays a critical role as a brake to turn down the transcription of cellulase genes to repress the overexpression of hydrolytic enzymes and prevent energy wastage. Transcriptional profiling analyses revealed that cellulase gene expression levels were maintained at high levels for 56 h in the Δstk-12 mutant, compared to only 8 h in the wild-type (WT) strain. After growth on cellulose for 3 days, the transcript levels of cellulase genes in the Δstk-12 mutant were 3.3-fold over WT, and clr-2 (encoding a transcriptional activator) was up-regulated in Δstk-12 while res-1 and rca-1 (encoding two cellulase repressors) were down-regulated. Consequently, total cellulase production in the Δstk-12 mutant was 7-fold higher than in the WT. These results strongly suggest that stk-12 deletion results in dysregulation of the cellulase expression machinery. Further analyses showed that STK-12 directly targets IGO-1 to regulate cellulase production. The TORC1 pathway promoted cellulase production, at least partly, by inhibiting STK-12 function, and STK-12 and CRE-1 functioned in parallel pathways to repress cellulase gene expression. Our results clarify how cellulase genes are repressed at the transcriptional level during cellulose induction, and highlight a new strategy to improve industrial fungal strains.
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Affiliation(s)
- Liangcai Lin
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Shanshan Wang
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Xiaolin Li
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Qun He
- State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - J. Philipp Benz
- Technical University of Munich, TUM School of Life Sciences Weihenstephan, Hans-Carl-von-Carlowitz-Platz, Freising, Germany
- Technical University of Munich, Institute for Advanced Study, Lichtenbergstr, Garching, Germany
| | - Chaoguang Tian
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- * E-mail:
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Li J, Gu S, Zhao Z, Chen B, Liu Q, Sun T, Sun W, Tian C. Dissecting cellobiose metabolic pathway and its application in biorefinery through consolidated bioprocessing in Myceliophthora thermophila. Fungal Biol Biotechnol 2019; 6:21. [PMID: 31754437 PMCID: PMC6852783 DOI: 10.1186/s40694-019-0083-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 11/04/2019] [Indexed: 02/08/2023] Open
Abstract
Background Lignocellulosic biomass has long been recognized as a potential sustainable source for industrial applications. The costs associated with conversion of plant biomass to fermentable sugar represent a significant barrier to the production of cost-competitive biochemicals. Consolidated bioprocessing (CBP) is considered a potential breakthrough for achieving cost-efficient production of biomass-based fuels and commodity chemicals. During the degradation of cellulose, cellobiose (major end-product of cellulase activity) is catabolized by hydrolytic and phosphorolytic pathways in cellulolytic organisms. However, the details of the two intracellular cellobiose metabolism pathways in cellulolytic fungi remain to be uncovered. Results Using the engineered malic acid production fungal strain JG207, we demonstrated that the hydrolytic pathway by β-glucosidase and the phosphorolytic pathway by phosphorylase are both used for intracellular cellobiose metabolism in Myceliophthora thermophila, and the yield of malic acid can benefit from the energy advantages of phosphorolytic cleavage. There were obvious differences in regulation of the two cellobiose catabolic pathways depending on whether M. thermophila JG207 was grown on cellobiose or Avicel. Disruption of Mtcpp in strain JG207 led to decreased production of malic acid under cellobiose conditions, while expression levels of all three intracellular β-glucosidase genes were significantly up-regulated to rescue the impairment of the phosphorolytic pathway under Avicel conditions. When the flux of the hydrolytic pathway was reduced, we found that β-glucosidase encoded by bgl1 was the dominant enzyme in the hydrolytic pathway and deletion of bgl1 resulted in significant enhancement of protein secretion but reduction of malate production. Combining comprehensive manipulation of both cellobiose utilization pathways and enhancement of cellobiose uptake by overexpression of a cellobiose transporter, the final strain JG412Δbgl2Δbgl3 produced up to 101.2 g/L and 77.4 g/L malic acid from cellobiose and Avicel, respectively, which corresponded to respective yields of 1.35 g/g and 1.03 g/g, representing significant improvement over the starting strain JG207. Conclusions This is the first report of detailed investigation of intracellular cellobiose catabolism in cellulolytic fungus M. thermophila. These results provide insights that can be applied to industrial fungi for production of biofuels and biochemicals from cellobiose and cellulose.
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Affiliation(s)
- Jingen Li
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Shuying Gu
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Zhen Zhao
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Bingchen Chen
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Qian Liu
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Tao Sun
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Wenliang Sun
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Chaoguang Tian
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
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Eliodório KP, Cunha GCDGE, Müller C, Lucaroni AC, Giudici R, Walker GM, Alves SL, Basso TO. Advances in yeast alcoholic fermentations for the production of bioethanol, beer and wine. ADVANCES IN APPLIED MICROBIOLOGY 2019; 109:61-119. [PMID: 31677647 DOI: 10.1016/bs.aambs.2019.10.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Yeasts have a long-standing relationship with humankind that has widened in recent years to encompass production of diverse foods, beverages, fuels and medicines. Here, key advances in the field of yeast fermentation applied to alcohol production, which represents the predominant product of industrial biotechnology, will be presented. More specifically, we have selected industries focused in producing bioethanol, beer and wine. In these bioprocesses, yeasts from the genus Saccharomyces are still the main players, with Saccharomyces cerevisiae recognized as the preeminent industrial ethanologen. However, the growing demand for new products has opened the door to diverse yeasts, including non-Saccharomyces strains. Furthermore, the development of synthetic media that successfully simulate industrial fermentation medium will be discussed along with a general overview of yeast fermentation modeling.
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Affiliation(s)
| | | | - Caroline Müller
- Laboratory of Biochemistry and Genetics, Federal University of Fronteira Sul, Chapecó, SC, Brazil
| | - Ana Carolina Lucaroni
- Laboratory of Biochemistry and Genetics, Federal University of Fronteira Sul, Chapecó, SC, Brazil
| | - Reinaldo Giudici
- Department of Chemical Engineering, University of São Paulo, São Paulo, SP, Brazil
| | | | - Sérgio Luiz Alves
- Laboratory of Biochemistry and Genetics, Federal University of Fronteira Sul, Chapecó, SC, Brazil
| | - Thiago Olitta Basso
- Department of Chemical Engineering, University of São Paulo, São Paulo, SP, Brazil.
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Kim HJ, Lee WH, Turner TL, Kwak S, Jin YS. An extra copy of the β-glucosidase gene improved the cellobiose fermentation capability of an engineered Saccharomyces cerevisiae strain. 3 Biotech 2019; 9:367. [PMID: 31588391 DOI: 10.1007/s13205-019-1899-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Accepted: 09/16/2019] [Indexed: 01/06/2023] Open
Abstract
In a previously engineered Saccharomyces cerevisiae recombinant, the cellobiose fermentation rate was significantly lower than the glucose fermentation rate. Thus, we implemented a genome-wide perturbation library to find gene targets for improving the cellobiose fermentation capability of the yeast strain. Unexpectedly, we discovered a transformant that contained an additional β-glucosidase gene (gh1-1), possibly through homologous recombination between the plasmids. The additional β-glucosidase led to the fastest cellobiose fermentation activity among all the transformants evaluated, and the strain demonstrated significantly higher β-glucosidase activity than the control strain, especially during the initial exponential growth phase. The present work revealed the benefit of the extra gh1-1 copy for efficient cellobiose fermentation in the engineered S. cerevisiae strain.
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Affiliation(s)
- Hyo Jin Kim
- 1Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
- 2Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
- 3Graduate School of International Agricultural Technology, Seoul National University, Pyeongchang, 25354 Republic of Korea
- 4Institutes of Green Bio Science and Technology, Seoul National University, Pyeongchang, 25354 Republic of Korea
| | - Won-Heong Lee
- 1Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
- 2Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
- 5Bioenergy Science and Technology, Chonnam National University, Gwangju, 61186 Korea
| | - Timothy Lee Turner
- 1Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
- 2Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
- 6Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611 USA
| | - Suryang Kwak
- 1Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
- 2Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
| | - Yong-Su Jin
- 1Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
- 2Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
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Tarraran L, Mazzoli R. Alternative strategies for lignocellulose fermentation through lactic acid bacteria: the state of the art and perspectives. FEMS Microbiol Lett 2019; 365:4995910. [PMID: 30007320 DOI: 10.1093/femsle/fny126] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 05/11/2018] [Indexed: 12/22/2022] Open
Abstract
Lactic acid bacteria (LAB) have a long history in industrial processes as food starters and biocontrol agents, and also as producers of high-value compounds. Lactic acid, their main product, is among the most requested chemicals because of its multiple applications, including the synthesis of biodegradable plastic polymers. Moreover, LAB are attractive candidates for the production of ethanol, polyhydroalkanoates, sweeteners and exopolysaccharides. LAB generally have complex nutritional requirements. Furthermore, they cannot directly ferment inexpensive feedstocks such as lignocellulose. This significantly increases the cost of LAB fermentation and hinders its application in the production of high volumes of low-cost chemicals. Different strategies have been explored to extend LAB fermentation to lignocellulosic biomass. Fermentation of lignocellulose hydrolysates by LAB has been frequently reported and is the most mature technology. However, current economic constraints of this strategy have driven research for alternative approaches. Co-cultivation of LAB with native cellulolytic microorganisms may reduce the high cost of exogenous cellulase supplementation. Special attention is given in this review to the construction of recombinant cellulolytic LAB by metabolic engineering, which may generate strains able to directly ferment plant biomass. The state of the art of these strategies is illustrated along with perspectives of their applications to industrial second generation biorefinery processes.
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Affiliation(s)
- Loredana Tarraran
- Structural and Functional Biochemistry, Laboratory of Proteomics and Metabolic Engineering of Prokaryotes, Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123 Torino, Italy
| | - Roberto Mazzoli
- Structural and Functional Biochemistry, Laboratory of Proteomics and Metabolic Engineering of Prokaryotes, Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123 Torino, Italy
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Deficiency of β-Glucosidase Beneficial for the Simultaneous Saccharification and Lipid Production by the Oleaginous Yeast Lipomyces starkeyi. Appl Biochem Biotechnol 2019; 190:745-757. [PMID: 31485895 DOI: 10.1007/s12010-019-03129-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 08/25/2019] [Indexed: 10/26/2022]
Abstract
It is inevitably for cellobiose to be co-generated during enzymatic hydrolysis of cellulose, especially when the cellulase is lack of β-glucosidase activity. In the present study, cellobiose was found superior to glucose for cell growth by L. starkeyi, regardless of the sugar concentrations. Glucose was assimilated preferentially when cellobiose and glucose were co-fermented. Deficiency of β-glucosidase was observed to be beneficial for the simultaneous saccharification and lipid production (SSLP). High lipid titer and cellulose conversion of 9.1 g/L and 92.4%, respectively, were achieved when cellulase with low β-glucosidase activity was supplemented. The SSLP achieved higher lipid titer of 9.5 g/L when a pre-hydrolysis process was introduced. The glucosidase generated by L. starkeyi was primarily cell-bound, which contributed significantly to the cellobiose utilization and the high lipid production. These results provided a novel scheme for enhanced lipid production from lignocellulosic biomass with reduced enzyme usage, which is believed to facilitate the design of a more cost-effective lignocellulose-to-lipid route.
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Turner TL, Lane S, Jayakody LN, Zhang GC, Kim H, Cho W, Jin YS. Deletion of JEN1 and ADY2 reduces lactic acid yield from an engineered Saccharomyces cerevisiae, in xylose medium, expressing a heterologous lactate dehydrogenase. FEMS Yeast Res 2019; 19:5556531. [DOI: 10.1093/femsyr/foz050] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 08/27/2019] [Indexed: 11/14/2022] Open
Abstract
ABSTRACT
Microorganisms have evolved to produce specific end products for many reasons, including maintaining redox balance between NAD+ and NADH. The yeast Saccharomyces cerevisiae, for example, produces ethanol as a primary end product from glucose for the regeneration of NAD+. Engineered S. cerevisiae strains have been developed to ferment lignocellulosic sugars, such as xylose, to produce lactic acid by expression of a heterologous lactate dehydrogenase (ldhA from Rhizopus oryzae) without genetic perturbation to the native ethanol pathway. Surprisingly, the engineered yeast strains predominantly produce ethanol from glucose, but produce lactic acid as the major product from xylose. Here, we provide initial evidence that the shift in product formation from ethanol to lactic acid during xylose fermentation is at least partially dependent on the presence of functioning monocarboxylate transporter genes/proteins, including JEN1 and ADY2, which are downregulated and unstable in the presence of glucose, but upregulated/stable on xylose. Future yeast metabolic engineering studies may find the feedstock/carbon selection, such as xylose, an important step toward improving the yield of target end products.
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Affiliation(s)
- Timothy L Turner
- Department of Food Science and Human Nutrition, 260 Bevier Hall, 905 South Goodwin Avenue, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Stephan Lane
- Department of Food Science and Human Nutrition, 260 Bevier Hall, 905 South Goodwin Avenue, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Carl R. Woese Institute for Genomic Biology, 1206 West Gregory Avenue, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Lahiru N Jayakody
- Department of Food Science and Human Nutrition, 260 Bevier Hall, 905 South Goodwin Avenue, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Guo-Chang Zhang
- Department of Food Science and Human Nutrition, 260 Bevier Hall, 905 South Goodwin Avenue, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Heejin Kim
- Department of Food Science and Human Nutrition, 260 Bevier Hall, 905 South Goodwin Avenue, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Carl R. Woese Institute for Genomic Biology, 1206 West Gregory Avenue, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Whiyeon Cho
- Department of Food Science and Human Nutrition, 260 Bevier Hall, 905 South Goodwin Avenue, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Yong-Su Jin
- Department of Food Science and Human Nutrition, 260 Bevier Hall, 905 South Goodwin Avenue, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Carl R. Woese Institute for Genomic Biology, 1206 West Gregory Avenue, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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Guirimand GGY, Bamba T, Matsuda M, Inokuma K, Morita K, Kitada Y, Kobayashi Y, Yukawa T, Sasaki K, Ogino C, Hasunuma T, Kondo A. Combined Cell Surface Display of β‐
d
‐Glucosidase (BGL), Maltose Transporter (MAL11), and Overexpression of Cytosolic Xylose Reductase (XR) in
Saccharomyces cerevisiae
Enhance Cellobiose/Xylose Coutilization for Xylitol Bioproduction from Lignocellulosic Biomass. Biotechnol J 2019; 14:e1800704. [DOI: 10.1002/biot.201800704] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 06/10/2019] [Indexed: 12/28/2022]
Affiliation(s)
- Gregory G. Y. Guirimand
- Graduate School of Science, Technology and InnovationKobe University 1‐1 Rokkodai 657‐8501 Nada Kobe Japan
- Engineering Biology Research CenterKobe University 1‐1 Rokkodai 657‐8501 Nada Kobe Japan
| | - Takahiro Bamba
- Graduate School of Science, Technology and InnovationKobe University 1‐1 Rokkodai 657‐8501 Nada Kobe Japan
| | - Mami Matsuda
- Graduate School of Science, Technology and InnovationKobe University 1‐1 Rokkodai 657‐8501 Nada Kobe Japan
| | - Kentaro Inokuma
- Graduate School of Science, Technology and InnovationKobe University 1‐1 Rokkodai 657‐8501 Nada Kobe Japan
- Engineering Biology Research CenterKobe University 1‐1 Rokkodai 657‐8501 Nada Kobe Japan
| | - Kenta Morita
- Department of Chemical Science and Engineering, Graduate School of EngineeringKobe University 1‐1 Rokkodai 657‐8501 Nada Kobe Japan
- Research Facility Center for Science and TechnologyKobe University 1‐1 Rokkodai 657‐8501 Nada Kobe Japan
| | - Yuki Kitada
- Graduate School of Science, Technology and InnovationKobe University 1‐1 Rokkodai 657‐8501 Nada Kobe Japan
| | - Yuma Kobayashi
- Graduate School of Science, Technology and InnovationKobe University 1‐1 Rokkodai 657‐8501 Nada Kobe Japan
| | - Takahiro Yukawa
- Graduate School of Science, Technology and InnovationKobe University 1‐1 Rokkodai 657‐8501 Nada Kobe Japan
| | - Kengo Sasaki
- Graduate School of Science, Technology and InnovationKobe University 1‐1 Rokkodai 657‐8501 Nada Kobe Japan
- Engineering Biology Research CenterKobe University 1‐1 Rokkodai 657‐8501 Nada Kobe Japan
| | - Chiaki Ogino
- Engineering Biology Research CenterKobe University 1‐1 Rokkodai 657‐8501 Nada Kobe Japan
- Department of Chemical Science and Engineering, Graduate School of EngineeringKobe University 1‐1 Rokkodai 657‐8501 Nada Kobe Japan
| | - Tomohisa Hasunuma
- Graduate School of Science, Technology and InnovationKobe University 1‐1 Rokkodai 657‐8501 Nada Kobe Japan
- Engineering Biology Research CenterKobe University 1‐1 Rokkodai 657‐8501 Nada Kobe Japan
| | - Akihiko Kondo
- Graduate School of Science, Technology and InnovationKobe University 1‐1 Rokkodai 657‐8501 Nada Kobe Japan
- Engineering Biology Research CenterKobe University 1‐1 Rokkodai 657‐8501 Nada Kobe Japan
- Department of Chemical Science and Engineering, Graduate School of EngineeringKobe University 1‐1 Rokkodai 657‐8501 Nada Kobe Japan
- Biomass Engineering ProgramRIKEN 1‐7‐22 Suehiro‐cho 230‐0045 Tsurumi‐ku, Yokohama Kanagawa Japan
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Crosstalk of Cellulose and Mannan Perception Pathways Leads to Inhibition of Cellulase Production in Several Filamentous Fungi. mBio 2019; 10:mBio.00277-19. [PMID: 31266859 PMCID: PMC6606794 DOI: 10.1128/mbio.00277-19] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In fungi, the production of enzymes for polysaccharide degradation is controlled by complex signaling networks. Previously, these networks were studied in response to simple sugars or single polysaccharides. Here, we tackled for the first time the molecular interplay between two seemingly unrelated perception pathways: those for cellulose and the hemicellulose (gluco)mannan. We identified a so far unknown competitive inhibition between the respective degradation products acting as signaling molecules. Competition was detected both at the level of the uptake and intracellularly, upstream of the main transcriptional regulator CLR-2. Our findings provide novel insights into the molecular communication between perception pathways. Also, they present possible targets for the improvement of industrial strains for higher cellulase production through the engineering of mannan insensitivity. It is essential for microbes to acquire information about their environment. Fungi use soluble degradation products of plant cell wall components to understand the substrate composition they grow on. Individual perception pathways have been well described. However, the interconnections between pathways remain poorly understood. In the present work, we provide evidence of crosstalk between the perception pathways for cellulose and the hemicellulose mannan being conserved in several filamentous fungi and leading to the inhibition of cellulase expression. We used the functional genomics tools available for Neurospora crassa to investigate this overlap at the molecular level. Crosstalk and competitive inhibition could be identified both during uptake by cellodextrin transporters and intracellularly. Importantly, the overlap is independent of CRE-1-mediated catabolite repression. These results provide novel insights into the regulatory networks of lignocellulolytic fungi and will contribute to the rational optimization of fungal enzyme production for efficient plant biomass depolymerization and utilization.
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63
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Effects of intron retention on properties of β-glucosidase in Aspergillus niger. Fungal Biol 2019; 123:465-470. [DOI: 10.1016/j.funbio.2019.04.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 02/03/2019] [Accepted: 04/09/2019] [Indexed: 01/20/2023]
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64
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Wu J, Dong L, Zhou C, Liu B, Feng L, Wu C, Qi Z, Cao G. Developing a coculture for enhanced butanol production by Clostridium beijerinckii and Saccharomyces cerevisiae. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.biteb.2019.03.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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65
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Wilken SE, Swift CL, Podolsky IA, Lankiewicz TS, Seppälä S, O'Malley MA. Linking ‘omics’ to function unlocks the biotech potential of non-model fungi. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.coisb.2019.02.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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66
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Cui J, Mai G, Wang Z, Liu Q, Zhou Y, Ma Y, Liu C. Metagenomic Insights Into a Cellulose-Rich Niche Reveal Microbial Cooperation in Cellulose Degradation. Front Microbiol 2019; 10:618. [PMID: 30984144 PMCID: PMC6447707 DOI: 10.3389/fmicb.2019.00618] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Accepted: 03/11/2019] [Indexed: 11/22/2022] Open
Abstract
Background Cellulose is the most abundant organic polymer mainly produced by plants in nature. It is insoluble and highly resistant to enzymatic hydrolysis. Cellulolytic microorganisms that are capable of producing a battery of related enzymes play an important role in recycling cellulose-rich plant biomass. Effective cellulose degradation by multiple synergic microorganisms has been observed within a defined microbial consortium in the lab culture. Metagenomic analysis may enable us to understand how microbes cooperate in cellulose degradation in a more complex microbial free-living ecosystem in nature. Results Here we investigated a typical cellulose-rich and alkaline niche where constituent microbes survive through inter-genera cooperation in cellulose utilization. The niche has been generated in an ancient paper-making plant, which has served as an isolated habitat for over 7 centuries. Combined amplicon-based sequencing of 16S rRNA genes and metagenomic sequencing, our analyses showed a microbial composition with 6 dominant genera including Cloacibacterium, Paludibacter, Exiguobacterium, Acetivibrio, Tolumonas, and Clostridium in this cellulose-rich niche; the composition is distinct from other cellulose-rich niches including a modern paper mill, bamboo soil, wild giant panda guts, and termite hindguts. In total, 11,676 genes of 96 glucoside hydrolase (GH) families, as well as 1,744 genes of carbohydrate transporters were identified, and modeling analysis of two representative genes suggested that these glucoside hydrolases likely evolved to adapt to alkaline environments. Further reconstruction of the microbial draft genomes by binning the assembled contigs predicted a mutualistic interaction between the dominant microbes regarding the cellulolytic process in the niche, with Paludibacter and Clostridium acting as helpers that produce endoglucanases, and Cloacibacterium, Exiguobacterium, Acetivibrio, and Tolumonas being beneficiaries that cross-feed on the cellodextrins by oligosaccharide uptake. Conclusion The analysis of the key genes involved in cellulose degradation and reconstruction of the microbial draft genomes by binning the assembled contigs predicted a mutualistic interaction based on public goods regarding the cellulolytic process in the niche, suggesting that in the studied microbial consortium, free-living bacteria likely survive on each other by acquisition and exchange of metabolites. Knowledge gained from this study will facilitate the design of complex microbial communities with a better performance in industrial bioprocesses.
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Affiliation(s)
- Jinming Cui
- Institute of Synthetic Biology - Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,Guangzhou Institute of Advanced Technology, Chinese Academy of Sciences, Guangzhou, China.,Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Guoqin Mai
- Institute of Synthetic Biology - Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Zuowei Wang
- Guangzhou Institute of Advanced Technology, Chinese Academy of Sciences, Guangzhou, China.,Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Quan Liu
- Institute of Synthetic Biology - Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Yan Zhou
- Institute of Synthetic Biology - Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Yingfei Ma
- Institute of Synthetic Biology - Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Chenli Liu
- Institute of Synthetic Biology - Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,Guangzhou Institute of Advanced Technology, Chinese Academy of Sciences, Guangzhou, China.,Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
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67
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Podolsky IA, Seppälä S, Lankiewicz TS, Brown JL, Swift CL, O'Malley MA. Harnessing Nature's Anaerobes for Biotechnology and Bioprocessing. Annu Rev Chem Biomol Eng 2019; 10:105-128. [PMID: 30883214 DOI: 10.1146/annurev-chembioeng-060718-030340] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Industrial biotechnology has the potential to decrease our reliance on petroleum for fuel and bio-based chemical production and also enable valorization of waste streams. Anaerobic microorganisms thrive in resource-limited environments and offer an array of novel bioactivities in this regard that could revolutionize biomanufacturing. However, they have not been adopted for widespread industrial use owing to their strict growth requirements, limited number of available strains, difficulty in scale-up, and genetic intractability. This review provides an overview of current and future uses for anaerobes in biotechnology and bioprocessing in the postgenomic era. We focus on the recently characterized anaerobic fungi (Neocallimastigomycota) native to the digestive tract of large herbivores, which possess a trove of enzymes, pathways, transporters, and other biomolecules that can be harnessed for numerous biotechnological applications. Resolving current genetic intractability, scale-up, and cultivation challenges will unlock the potential of these lignocellulolytic fungi and other nonmodel micro-organisms to accelerate bio-based production.
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Affiliation(s)
- Igor A Podolsky
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA; , , , , ,
| | - Susanna Seppälä
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA; , , , , ,
| | - Thomas S Lankiewicz
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA; , , , , ,
| | - Jennifer L Brown
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA; , , , , ,
| | - Candice L Swift
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA; , , , , ,
| | - Michelle A O'Malley
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA; , , , , ,
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68
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Li X, Chen Y, Nielsen J. Harnessing xylose pathways for biofuels production. Curr Opin Biotechnol 2019; 57:56-65. [PMID: 30785001 DOI: 10.1016/j.copbio.2019.01.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 01/04/2019] [Accepted: 01/15/2019] [Indexed: 01/02/2023]
Abstract
Energy security, environmental pollution, and economic development drive the development of alternatives to fossil fuels as an urgent global priority. Lignocellulosic biomass has the potential to contribute to meeting the demand for biofuel production via hydrolysis and fermentation of released sugars, such as glucose, xylose, and arabinose. Construction of robust cell factories requires introducing and rewiring of their metabolism to efficiently use all these sugars. Here, we review recent advances in re-constructing pathways for metabolism of pentoses, with special focus on xylose metabolism in the most widely used cell factories Saccharomyces cerevisiae and Escherichia coli. We also highlight engineering advanced biofuels-synthesis pathways and describes progress toward overcoming the challenges facing adoption of large-scale biofuel production.
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Affiliation(s)
- Xiaowei Li
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden; Novo Nordisk Foundation Center for Biosustainability, Chalmers University of Technology, Gothenburg, Sweden
| | - Yun Chen
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden; Novo Nordisk Foundation Center for Biosustainability, Chalmers University of Technology, Gothenburg, Sweden
| | - Jens Nielsen
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden; Novo Nordisk Foundation Center for Biosustainability, Chalmers University of Technology, Gothenburg, Sweden; Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark; Wallenberg Center for Protein Research, Chalmers University of Technology, Gothenburg, Sweden.
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69
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Kong II, Turner TL, Kim H, Kim SR, Jin YS. Phenotypic evaluation and characterization of 21 industrial Saccharomyces cerevisiae yeast strains. FEMS Yeast Res 2019; 18:4794945. [PMID: 29325040 DOI: 10.1093/femsyr/foy001] [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: 10/15/2017] [Accepted: 01/08/2018] [Indexed: 12/18/2022] Open
Abstract
Microorganisms have been studied and used extensively to produce value-added fuels and chemicals. Yeasts, specifically Saccharomyces cerevisiae, receive industrial attention because of their well-known ability to ferment glucose and produce ethanol. Thousands of natural or genetically modified S. cerevisiae have been found in industrial environments for various purposes. These industrial strains are isolated from industrial fermentation sites, and they are considered as potential host strains for superior fermentation processes. In many cases, industrial yeast strains have higher thermotolerance, increased resistances towards fermentation inhibitors and increased glucose fermentation rates under anaerobic conditions when compared with laboratory yeast strains. Despite the advantages of industrial strains, they are often not well characterized. Through screening and phenotypic characterization of commercially available industrial yeast strains, industrial fermentation processes requiring specific environmental conditions may be able to select an ideal starting yeast strain to be further engineered. Here, we have characterized and compared 21 industrial S. cerevisiae strains under multiple conditions, including their tolerance to varying pH conditions, resistance to fermentation inhibitors, sporulation efficiency and ability to ferment lignocellulosic sugars. These data may be useful for the selection of a parental strain for specific biotechnological applications of engineered yeast.
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Affiliation(s)
- In Iok Kong
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Timothy Lee Turner
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Heejin Kim
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Soo Rin Kim
- School of Food Science and Biotechnology, Kyungpook National University, Daegu, Korea
| | - Yong-Su Jin
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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70
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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: 28] [Impact Index Per Article: 5.6] [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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71
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Zhang K, Lu X, Li Y, Jiang X, Liu L, Wang H. New technologies provide more metabolic engineering strategies for bioethanol production in Zymomonas mobilis. Appl Microbiol Biotechnol 2019; 103:2087-2099. [PMID: 30661108 DOI: 10.1007/s00253-019-09620-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 01/02/2019] [Accepted: 01/03/2019] [Indexed: 02/06/2023]
Abstract
Bioethanol has been considered as a potentially renewable energy source, and metabolic engineering plays an important role in the production of biofuels. As an efficient ethanol-producing bacterium, Zymomonas mobilis has garnered special attention due to its high sugar uptake, ethanol yield, and tolerance. Different metabolic engineering strategies have been used to establish new metabolic pathways for Z. mobilis to broaden its substrate range, remove competing pathways, and enhance its tolerance to ethanol and lignocellulosic hydrolysate inhibitors. Recent advances in omics technology, computational modeling and simulation, system biology, and synthetic biology contribute to the efficient re-design and manipulation of microbes via metabolic engineering at the whole-cell level. In this review, we summarize the progress of some new technologies used for metabolic engineering to improve bioethanol production and tolerance in Z. mobilis. Some successful examples of metabolic engineering used to develop strains for ethanol production are described in detail. Lastly, some important strategies for future metabolic engineering efforts are also highlighted.
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Affiliation(s)
- Kun Zhang
- Henan Province Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Xinxin Lu
- Henan Province Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Yi Li
- Henan Province Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Xiaobing Jiang
- Henan Province Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Lei Liu
- Henan Province Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Hailei Wang
- Henan Province Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang, 453007, Henan, China.
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72
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Hemansi, Gupta R, Yadav G, Kumar G, Yadav A, Saini JK, Kuhad RC. Second Generation Bioethanol Production: The State of Art. BIOFUEL AND BIOREFINERY TECHNOLOGIES 2019. [DOI: 10.1007/978-3-319-94797-6_8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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73
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Cellobiose fermentation by Saccharomyces cerevisiae: Comparative analysis of intra versus extracellular sugar hydrolysis. Process Biochem 2018. [DOI: 10.1016/j.procbio.2018.09.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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74
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Salgado JCS, Meleiro LP, Carli S, Ward RJ. Glucose tolerant and glucose stimulated β-glucosidases - A review. BIORESOURCE TECHNOLOGY 2018; 267:704-713. [PMID: 30093225 DOI: 10.1016/j.biortech.2018.07.137] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 07/24/2018] [Accepted: 07/26/2018] [Indexed: 05/22/2023]
Abstract
The β-glucosidases (β-D-glucoside glucohydrolase, EC 3.2.1.21) hydrolyze glycosidic bonds of alkyl-, amino-, or aryl-β-D-glucosides, cyanogenic glucosides, disaccharides and short oligosaccharides and can also catalyze the synthesis of glycosyl-bonds between different molecules via transglycosylation. Due to their ubiquitous phylogenetic distribution, substrate diversity and ability to both hydrolyze and synthesize glycosidic bonds, the catalysis and regulation of β-glucosidases have been extensively studied. Many β-glucosidases are inhibited by the reaction product glucose, and reduced catalytic activity may limit the biotechnological and industrial applications of these enzymes and this has stimulated the search for β-glucosidases that maintain their activity at high glucose concentrations. Studies of many glucose tolerant enzymes have been reported and due to the ongoing interest in these enzymes, here it has been reviewed this accumulated body of knowledge which provides valuable insights as to the kinetics, structure, regulation and evolution of glucose tolerant and glucose stimulated β-glucosidases.
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Affiliation(s)
- José Carlos Santos Salgado
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Luana Parras Meleiro
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil.
| | - Sibeli Carli
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Richard John Ward
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
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75
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Vogler BW, Starkenburg SR, Sudasinghe N, Schambach JY, Rollin JA, Pattathil S, Barry AN. Characterization of plant carbon substrate utilization by Auxenochlorella protothecoides. ALGAL RES 2018. [DOI: 10.1016/j.algal.2018.07.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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76
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Lane S, Dong J, Jin YS. Value-added biotransformation of cellulosic sugars by engineered Saccharomyces cerevisiae. BIORESOURCE TECHNOLOGY 2018; 260:380-394. [PMID: 29655899 DOI: 10.1016/j.biortech.2018.04.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2018] [Revised: 03/31/2018] [Accepted: 04/02/2018] [Indexed: 05/26/2023]
Abstract
The substantial research efforts into lignocellulosic biofuels have generated an abundance of valuable knowledge and technologies for metabolic engineering. In particular, these investments have led to a vast growth in proficiency of engineering the yeast Saccharomyces cerevisiae for consuming lignocellulosic sugars, enabling the simultaneous assimilation of multiple carbon sources, and producing a large variety of value-added products by introduction of heterologous metabolic pathways. While microbial conversion of cellulosic sugars into large-volume low-value biofuels is not currently economically feasible, there may still be opportunities to produce other value-added chemicals as regulation of cellulosic sugar metabolism is quite different from glucose metabolism. This review summarizes these recent advances with an emphasis on employing engineered yeast for the bioconversion of lignocellulosic sugars into a variety of non-ethanol value-added products.
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Affiliation(s)
- Stephan Lane
- Carl Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Jia Dong
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Yong-Su Jin
- Carl Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
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77
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Yu S, Liu JJ, Yun EJ, Kwak S, Kim KH, Jin YS. Production of a human milk oligosaccharide 2'-fucosyllactose by metabolically engineered Saccharomyces cerevisiae. Microb Cell Fact 2018; 17:101. [PMID: 29950173 PMCID: PMC6020385 DOI: 10.1186/s12934-018-0947-2] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 06/16/2018] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND 2'-Fucosyllactose (2-FL), one of the most abundant oligosaccharides in human milk, has potential applications in foods due to its health benefits such as the selective promotion of bifidobacterial growth and the inhibition of pathogenic microbial binding to the human gut. Owing to the limited amounts of 2-FL in human milk, alternative microbial production of 2-FL is considered promising. To date, microbial production of 2-FL has been studied mostly in Escherichia coli. In this study, 2-FL was produced alternatively by using a yeast Saccharomyces cerevisiae, which may have advantages over E. coli. RESULTS Fucose and lactose were used as the substrates for the salvage pathway which was constructed with fkp coding for a bifunctional enzyme exhibiting L-fucokinase and guanosine 5'-diphosphate-L-fucose phosphorylase activities, fucT2 coding for α-1,2-fucosyltransferase, and LAC12 coding for lactose permease. Production of 2-FL by the resulting engineered yeast was verified by mass spectrometry. 2-FL titers of 92 and 503 mg/L were achieved from 48-h batch fermentation and 120-h fed-batch fermentation fed with ethanol as a carbon source, respectively. CONCLUSIONS This is the first report on 2-FL production by using yeast S. cerevisiae. These results suggest that S. cerevisiae can be considered as a host engineered for producing 2-FL via the salvage pathway.
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Affiliation(s)
- Sora Yu
- Department of Biotechnology, Graduate School, Korea University, Seoul, 02841 South Korea
| | - Jing-Jing Liu
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
| | - Eun Ju Yun
- Department of Biotechnology, Graduate School, Korea University, Seoul, 02841 South Korea
| | - Suryang Kwak
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
| | - Kyoung Heon Kim
- Department of Biotechnology, Graduate School, Korea University, Seoul, 02841 South Korea
| | - Yong-Su Jin
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
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78
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Co-fermentation of cellobiose and xylose by mixed culture of recombinant Saccharomyces cerevisiae and kinetic modeling. PLoS One 2018; 13:e0199104. [PMID: 29940003 PMCID: PMC6016917 DOI: 10.1371/journal.pone.0199104] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Accepted: 05/31/2018] [Indexed: 11/19/2022] Open
Abstract
Efficient conversion of cellulosic sugars in cellulosic hydrolysates is important for economically viable production of biofuels from lignocellulosic biomass, but the goal remains a critical challenge. The present study reports a new approach for simultaneous fermentation of cellobiose and xylose by using the co-culture consisting of recombinant Saccharomyces cerevisiae specialist strains. The co-culture system can provide competitive advantage of modularity compared to the single culture system and can be tuned to deal with fluctuations in feedstock composition to achieve robust and cost-effective biofuel production. This study characterized fermentation kinetics of the recombinant cellobiose-consuming S. cerevisiae strain EJ2, xylose-consuming S. cerevisiae strain SR8, and their co-culture. The motivation for kinetic modeling was to provide guidance and prediction of using the co-culture system for simultaneous fermentation of mixed sugars with adjustable biomass of each specialist strain under different substrate concentrations. The kinetic model for the co-culture system was developed based on the pure culture models and incorporated the effects of product inhibition, initial substrate concentration and inoculum size. The model simulations were validated by results from independent fermentation experiments under different substrate conditions, and good agreement was found between model predictions and experimental data from batch fermentation of cellobiose, xylose and their mixtures. Additionally, with the guidance of model prediction, simultaneous co-fermentation of 60 g/L cellobiose and 20 g/L xylose was achieved with the initial cell densities of 0.45 g dry cell weight /L for EJ2 and 0.9 g dry cell weight /L SR8. The results demonstrated that the kinetic modeling could be used to guide the design and optimization of yeast co-culture conditions for achieving simultaneous fermentation of cellobiose and xylose with improved ethanol productivity, which is critically important for robust and efficient renewable biofuel production from lignocellulosic biomass.
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Kim H, Oh EJ, Lane ST, Lee WH, Cate JH, Jin YS. Enhanced cellobiose fermentation by engineered Saccharomyces cerevisiae expressing a mutant cellodextrin facilitator and cellobiose phosphorylase. J Biotechnol 2018; 275:53-59. [DOI: 10.1016/j.jbiotec.2018.04.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 08/28/2017] [Accepted: 04/12/2018] [Indexed: 10/17/2022]
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80
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The heterologous expression potential of an acid-tolerant Talaromyces pinophilus β-glucosidase in Saccharomyces cerevisiae. Folia Microbiol (Praha) 2018; 63:725-734. [DOI: 10.1007/s12223-018-0613-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 05/14/2018] [Indexed: 10/16/2022]
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81
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Hara KY, Kobayashi J, Yamada R, Sasaki D, Kuriya Y, Hirono-Hara Y, Ishii J, Araki M, Kondo A. Transporter engineering in biomass utilization by yeast. FEMS Yeast Res 2018; 17:4097189. [PMID: 28934416 DOI: 10.1093/femsyr/fox061] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 08/04/2017] [Indexed: 12/17/2022] Open
Abstract
Biomass resources are attractive carbon sources for bioproduction because of their sustainability. Many studies have been performed using biomass resources to produce sugars as carbon sources for cell factories. Expression of biomass hydrolyzing enzymes in cell factories is an important approach for constructing biomass-utilizing bioprocesses because external addition of these enzymes is expensive. In particular, yeasts have been extensively engineered to be cell factories that directly utilize biomass because of their manageable responses to many genetic engineering tools, such as gene expression, deletion and editing. Biomass utilizing bioprocesses have also been developed using these genetic engineering tools to construct metabolic pathways. However, sugar input and product output from these cells are critical factors for improving bioproduction along with biomass utilization and metabolic pathways. Transporters are key components for efficient input and output activities. In this review, we focus on transporter engineering in yeast to enhance bioproduction from biomass resources.
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Affiliation(s)
- Kiyotaka Y Hara
- Division of Environmental and Life Sciences, Graduate Division of Nutritional and Environmental Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.,School of Food and Nutritional Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan
| | - Jyumpei Kobayashi
- Graduate School of Science, Technology, and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-8501, Japan
| | - Ryosuke Yamada
- Department of Chemical Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan
| | - Daisuke Sasaki
- Graduate School of Science, Technology, and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-8501, Japan
| | - Yuki Kuriya
- Graduate School of Science, Technology, and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-8501, Japan
| | - Yoko Hirono-Hara
- School of Food and Nutritional Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan
| | - Jun Ishii
- Graduate School of Science, Technology, and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-8501, Japan
| | - Michihiro Araki
- Graduate School of Science, Technology, and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-8501, Japan.,Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Syogoin, Sakyo-ku, Kyoto 606-8507, Japan
| | - Akihiko Kondo
- Graduate School of Science, Technology, and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-8501, Japan.,Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-8501, Japan
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Matsu-ura T, Dovzhenok AA, Coradetti ST, Subramanian KR, Meyer DR, Kwon JJ, Kim C, Salomonis N, Glass NL, Lim S, Hong CI. Synthetic Gene Network with Positive Feedback Loop Amplifies Cellulase Gene Expression in Neurospora crassa. ACS Synth Biol 2018; 7:1395-1405. [PMID: 29625007 DOI: 10.1021/acssynbio.8b00011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Second-generation or lignocellulosic biofuels are a tangible source of renewable energy, which is critical to combat climate change by reducing the carbon footprint. Filamentous fungi secrete cellulose-degrading enzymes called cellulases, which are used for production of lignocellulosic biofuels. However, inefficient production of cellulases is a major obstacle for industrial-scale production of second-generation biofuels. We used computational simulations to design and implement synthetic positive feedback loops to increase gene expression of a key transcription factor, CLR-2, that activates a large number of cellulases in a filamentous fungus, Neurospora crassa. Overexpression of CLR-2 reveals previously unappreciated roles of CLR-2 in lignocellulosic gene network, which enabled simultaneous induction of approximately 50% of 78 lignocellulosic degradation-related genes in our engineered Neurospora strains. This engineering results in dramatically increased cellulase activity due to cooperative orchestration of multiple enzymes involved in the cellulose degradation pathway. Our work provides a proof of principle in utilizing mathematical modeling and synthetic biology to improve the efficiency of cellulase synthesis for second-generation biofuel production.
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Affiliation(s)
- Toru Matsu-ura
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, Ohio 45267-0529, United States
| | - Andrey A. Dovzhenok
- Department of Mathematical Sciences, University of Cincinnati, Cincinnati, Ohio 45221-0025, United States
| | - Samuel T. Coradetti
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, United States
| | - Krithika R. Subramanian
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, Ohio 45267-0529, United States
- Department of Biomedical Informatics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio 45229-3039, United States
| | - Daniel R. Meyer
- Department of Biomedical, Chemical, and Environmental Engineering, University of Cincinnati, Cincinnati, Ohio 45221-0012, United States
| | - Jaesang J. Kwon
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, Ohio 45267-0529, United States
| | - Caleb Kim
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, Ohio 45267-0529, United States
| | - Nathan Salomonis
- Department of Biomedical Informatics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio 45229-3039, United States
- Division of Developmental Biology, Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio 45229-3039, United States
| | - N. Louise Glass
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, United States
| | - Sookkyung Lim
- Department of Mathematical Sciences, University of Cincinnati, Cincinnati, Ohio 45221-0025, United States
| | - Christian I. Hong
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, Ohio 45267-0529, United States
- Division of Developmental Biology, Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio 45229-3039, United States
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Turner TL, Kim H, Kong II, Liu JJ, Zhang GC, Jin YS. Engineering and Evolution of Saccharomyces cerevisiae to Produce Biofuels and Chemicals. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2018; 162:175-215. [PMID: 27913828 DOI: 10.1007/10_2016_22] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
To mitigate global climate change caused partly by the use of fossil fuels, the production of fuels and chemicals from renewable biomass has been attempted. The conversion of various sugars from renewable biomass into biofuels by engineered baker's yeast (Saccharomyces cerevisiae) is one major direction which has grown dramatically in recent years. As well as shifting away from fossil fuels, the production of commodity chemicals by engineered S. cerevisiae has also increased significantly. The traditional approaches of biochemical and metabolic engineering to develop economic bioconversion processes in laboratory and industrial settings have been accelerated by rapid advancements in the areas of yeast genomics, synthetic biology, and systems biology. Together, these innovations have resulted in rapid and efficient manipulation of S. cerevisiae to expand fermentable substrates and diversify value-added products. Here, we discuss recent and major advances in rational (relying on prior experimentally-derived knowledge) and combinatorial (relying on high-throughput screening and genomics) approaches to engineer S. cerevisiae for producing ethanol, butanol, 2,3-butanediol, fatty acid ethyl esters, isoprenoids, organic acids, rare sugars, antioxidants, and sugar alcohols from glucose, xylose, cellobiose, galactose, acetate, alginate, mannitol, arabinose, and lactose.
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Affiliation(s)
- Timothy L Turner
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Heejin Kim
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - In Iok Kong
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Jing-Jing Liu
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Guo-Chang Zhang
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Yong-Su Jin
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA. .,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
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84
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Nogueira KMV, de Paula RG, Antoniêto ACC, dos Reis TF, Carraro CB, Silva AC, Almeida F, Rechia CGV, Goldman GH, Silva RN. Characterization of a novel sugar transporter involved in sugarcane bagasse degradation in Trichoderma reesei. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:84. [PMID: 29619080 PMCID: PMC5879799 DOI: 10.1186/s13068-018-1084-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 03/17/2018] [Indexed: 05/05/2023]
Abstract
BACKGROUND Trichoderma reesei is a saprophytic fungus implicated in the degradation of polysaccharides present in the cell wall of plants. T. reesei has been recognized as the most important industrial fungus that secretes and produces cellulase enzymes that are employed in the production of second generation bioethanol. A few of the molecular mechanisms involved in the process of biomass deconstruction by T. reesei; in particular, the effect of sugar transporters and induction of xylanases and cellulases expression are yet to be known. RESULTS In our study, we characterized a novel sugar transporter, which was previously identified by our group through in silico analysis of RNA-seq data. The novel T. reesei 69957-sugar transport system (Tr69957) is capable of transporting xylose, mannose, and cellobiose using a T. reesei 69957-sugar transport system in Saccharomyces cerevisiae. The deletion of Tr69957 in T. reesei affected the fungal growth and biomass accumulation, and the sugar uptake in the presence of mannose, cellobiose, and xylose. Molecular docking studies revealed that Tr69957 shows reduced protein-ligand binding energy for interactions towards disaccharides in comparison with monosaccharides. Furthermore, the deletion of Tr69957 affected the gene expression of cellobiohydrolases (cel7a and cel6a), β-glucosidases (cel3a and cel1a), and xylanases (xyn1 and xyn2) in the cultures of parental and mutant strains in the presence of cellobiose and sugarcane bagasse (SCB). CONCLUSION The transporter Tr69957 of T. reesei can transport cellobiose, xylose, and mannose, and can affect the expression of a few genes encoding enzymes, such as cellulases and xylanases, in the presence of SCB. We showed for the first time that a filamentous fungus (T. reesei) contains a potential mannose transporter that may be involved in the degradation of cellulose.
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Affiliation(s)
- Karoline M. V. Nogueira
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP Brazil
| | - Renato Graciano de Paula
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP Brazil
| | | | - Thaila F. dos Reis
- Department of Pharmaceutical Sciences, Faculty of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP Brazil
| | - Cláudia Batista Carraro
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP Brazil
| | - Alinne Costa Silva
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP Brazil
| | - Fausto Almeida
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP Brazil
| | - Carem Gledes Vargas Rechia
- Department of Pharmaceutical Sciences, Faculty of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP Brazil
| | - Gustavo H. Goldman
- Department of Pharmaceutical Sciences, Faculty of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP Brazil
| | - Roberto N. Silva
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP Brazil
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85
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Chang JJ, Lin YJ, Lay CH, Thia C, Wu YC, Hou YH, Huang CC, Li WH. Constructing a cellulosic yeast host with an efficient cellulase cocktail. Biotechnol Bioeng 2017; 115:751-761. [PMID: 29197184 DOI: 10.1002/bit.26507] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 10/26/2017] [Accepted: 11/28/2017] [Indexed: 01/13/2023]
Abstract
Cellulose is a renewable feedstock for green industry. It is therefore important to develop a technique to construct a host with a high cellulolytic efficiency to digest cellulose. In this study, we developed a convenient host-engineering technique to adjust the expression levels of heterologous genes in the host by promoter rearrangement and gene copy number adjustment. Using genes from different glycoside hydrolase (GH) families including GH2, GH3, GH5, GH6, GH7, and GH12 from Aspergillus niger, Trichoderma reesei, and Neocallimastix patriciarum, we constructed a cellulolytic Kluyveromyces marxianus with eight cellulase gene-cassettes that produced a cellulase cocktail with a high cellulolytic efficiency, leading to a significant reduction in enzyme cost in a rice straw saccharification process. Our technique can be used to design a host that can efficiently convert biomass feedstock to biofuel.
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Affiliation(s)
- Jui-Jen Chang
- Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan.,Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
| | - Yu-Ju Lin
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan.,Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan
| | - Chyi-How Lay
- Master Program of Green Energy Science and Technology, Feng Chia University, Taichung, Taiwan.,Green Energy Development Center, Feng Chia University, Taichung, Taiwan
| | - Caroline Thia
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
| | - Yueh-Chin Wu
- Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan
| | - Yu-Han Hou
- Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan
| | - Chieh-Chen Huang
- Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan
| | - Wen-Hsiung Li
- Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan.,Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
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86
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Oh EJ, Kwak S, Kim H, Jin YS. Transporter engineering for cellobiose fermentation under lower pH conditions by engineered Saccharomyces cerevisiae. BIORESOURCE TECHNOLOGY 2017; 245:1469-1475. [PMID: 28583406 DOI: 10.1016/j.biortech.2017.05.138] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Revised: 05/19/2017] [Accepted: 05/21/2017] [Indexed: 06/07/2023]
Abstract
The aim of this study was to engineer cellodextrin transporter 2 (CDT-2) from Neurospora crassa for improved cellobiose fermentation under lower pH conditions by Saccharomyces cerevisiae. Through directed evolution, a mutant CDT-2 capable of facilitating cellobiose fermentation under lower pH conditions was obtained. Specifically, a library of CDT-2 mutants with GFP fusion was screened by flow cytometry and then serial subcultured to isolate a CDT-2 mutant capable of transporting cellobiose under acidic conditions. The engineered S. cerevisiae expressing the isolated mutant CDT-2 (I96N/T487A) produced ethanol with a specific cellobiose consumption rate of 0.069g/gcell/h, which was 51% and 55% higher than those of the strains harboring wild-type CDT-1 and CDT-2 in a minimal medium with 2g/L of acetic acid.
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Affiliation(s)
- Eun Joong Oh
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Suryang Kwak
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Heejin Kim
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Yong-Su Jin
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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87
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Jin YS, Cate JHD. Metabolic engineering of yeast for lignocellulosic biofuel production. Curr Opin Chem Biol 2017; 41:99-106. [DOI: 10.1016/j.cbpa.2017.10.025] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 10/16/2017] [Accepted: 10/20/2017] [Indexed: 01/04/2023]
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88
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Li Z, Liu G, Qu Y. Improvement of cellulolytic enzyme production and performance by rational designing expression regulatory network and enzyme system composition. BIORESOURCE TECHNOLOGY 2017; 245:1718-1726. [PMID: 28684177 DOI: 10.1016/j.biortech.2017.06.120] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 06/19/2017] [Accepted: 06/20/2017] [Indexed: 06/07/2023]
Abstract
Filamentous fungi are considered as the most efficient producers expressing lignocellulose-degrading enzymes. Penicillium oxalicum strains possess extraordinary fungal lignocellulolytic enzyme systems and can efficiently utilize plant biomass. In recent years, the regulatory aspects of production of hydrolytic enzymes by P. oxalicum have been well established. This review aims to discuss the recent developments for the production of lignocellulolytic enzymes by P. oxalicum. The main cellulolytic transcription factors mediating the complex transcriptional-regulatory network are highlighted. The genome-wide identification of cellulolytic transcription factors, the cascade regulation network for cellulolytic gene expression, and the synergistic and dose-controlled regulation by cellulolytic regulators are discussed. A cellulase regulatory network sensitive to inducers in intracellular environments, the cross-talk of regulation of lignocellulose-degrading enzyme and amylase, and accessory enzymes are also demonstrated. Finally, strategies for the metabolic engineering of P. oxalicum, which show promising applications in the enzymatic hydrolysis for biochemical production, are established.
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Affiliation(s)
- Zhonghai Li
- State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, China; Shandong Provincial Key Laboratory of Microbial Engineering, Department of Bioengineering, Qi Lu University of Technology, Jinan 250353, China
| | - Guodong Liu
- State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, China
| | - Yinbo Qu
- State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, China.
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Acosta-Sampson L, Döring K, Lin Y, Yu VY, Bukau B, Kramer G, Cate JHD. Role for ribosome-associated complex and stress-seventy subfamily B (RAC-Ssb) in integral membrane protein translation. J Biol Chem 2017; 292:19610-19627. [PMID: 28972146 PMCID: PMC5712606 DOI: 10.1074/jbc.m117.813857] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Indexed: 01/04/2023] Open
Abstract
Targeting of most integral membrane proteins to the endoplasmic reticulum is controlled by the signal recognition particle, which recognizes a hydrophobic signal sequence near the protein N terminus. Proper folding of these proteins is monitored by the unfolded protein response and involves protein degradation pathways to ensure quality control. Here, we identify a new pathway for quality control of major facilitator superfamily transporters that occurs before the first transmembrane helix, the signal sequence recognized by the signal recognition particle, is made by the ribosome. Increased rates of translation elongation of the N-terminal sequence of these integral membrane proteins can divert the nascent protein chains to the ribosome-associated complex and stress-seventy subfamily B chaperones. We also show that quality control of integral membrane proteins by ribosome-associated complex-stress-seventy subfamily B couples translation rate to the unfolded protein response, which has implications for understanding mechanisms underlying human disease and protein production in biotechnology.
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Affiliation(s)
| | - Kristina Döring
- the Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, Heidelberg D-69120, Germany
- the German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg D-69120, Germany, and
| | - Yuping Lin
- From the Departments of Molecular and Cell Biology and
| | - Vivian Y Yu
- From the Departments of Molecular and Cell Biology and
| | - Bernd Bukau
- the Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, Heidelberg D-69120, Germany
- the German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg D-69120, Germany, and
| | - Günter Kramer
- the Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, Heidelberg D-69120, Germany
- the German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg D-69120, Germany, and
| | - Jamie H D Cate
- From the Departments of Molecular and Cell Biology and
- Chemistry, University of California, Berkeley, California 94720
- the Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
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90
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Zhang C, Acosta-Sampson L, Yu VY, Cate JHD. Screening of transporters to improve xylodextrin utilization in the yeast Saccharomyces cerevisiae. PLoS One 2017; 12:e0184730. [PMID: 28886200 PMCID: PMC5591001 DOI: 10.1371/journal.pone.0184730] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 08/29/2017] [Indexed: 12/21/2022] Open
Abstract
The economic production of cellulosic biofuel requires efficient and full utilization of all abundant carbohydrates naturally released from plant biomass by enzyme cocktails. Recently, we reconstituted the Neurospora crassa xylodextrin transport and consumption system in Saccharomyces cerevisiae, enabling growth of yeast on xylodextrins aerobically. However, the consumption rate of xylodextrin requires improvement for industrial applications, including consumption in anaerobic conditions. As a first step in this improvement, we report analysis of orthologues of the N. crassa transporters CDT-1 and CDT-2. Transporter ST16 from Trichoderma virens enables faster aerobic growth of S. cerevisiae on xylodextrins compared to CDT-2. ST16 is a xylodextrin-specific transporter, and the xylobiose transport activity of ST16 is not inhibited by cellobiose. Other transporters identified in the screen also enable growth on xylodextrins including xylotriose. Taken together, these results indicate that multiple transporters might prove useful to improve xylodextrin utilization in S. cerevisiae. Efforts to use directed evolution to improve ST16 from a chromosomally-integrated copy were not successful, due to background growth of yeast on other carbon sources present in the selection medium. Future experiments will require increasing the baseline growth rate of the yeast population on xylodextrins, to ensure that the selective pressure exerted on xylodextrin transport can lead to isolation of improved xylodextrin transporters.
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Affiliation(s)
- Chenlu Zhang
- Department of Life Science, Tsinghua University, Beijing, China
| | - Ligia Acosta-Sampson
- Department of Molecular and Cell Biology, University of California, Berkeley, California, United States of America
| | - Vivian Yaci Yu
- Department of Molecular and Cell Biology, University of California, Berkeley, California, United States of America
| | - Jamie H. D. Cate
- Department of Molecular and Cell Biology, University of California, Berkeley, California, United States of America
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
- * E-mail:
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91
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Gandini C, Tarraran L, Kalemasi D, Pessione E, Mazzoli R. RecombinantLactococcus lactisfor efficient conversion of cellodextrins into L-lactic acid. Biotechnol Bioeng 2017; 114:2807-2817. [DOI: 10.1002/bit.26400] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 08/01/2017] [Accepted: 08/07/2017] [Indexed: 12/31/2022]
Affiliation(s)
- Chiara Gandini
- Department of Life Sciences and Systems Biology, Structural and Functional Biochemistry, Laboratory of Proteomics and Metabolic Engineering of Prokaryotes; University of Turin; Torino Italy
| | - Loredana Tarraran
- Department of Life Sciences and Systems Biology, Structural and Functional Biochemistry, Laboratory of Proteomics and Metabolic Engineering of Prokaryotes; University of Turin; Torino Italy
| | - Denis Kalemasi
- Department of Life Sciences and Systems Biology, Structural and Functional Biochemistry, Laboratory of Proteomics and Metabolic Engineering of Prokaryotes; University of Turin; Torino Italy
| | - Enrica Pessione
- Department of Life Sciences and Systems Biology, Structural and Functional Biochemistry, Laboratory of Proteomics and Metabolic Engineering of Prokaryotes; University of Turin; Torino Italy
| | - Roberto Mazzoli
- Department of Life Sciences and Systems Biology, Structural and Functional Biochemistry, Laboratory of Proteomics and Metabolic Engineering of Prokaryotes; University of Turin; Torino Italy
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92
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Parisutham V, Chandran SP, Mukhopadhyay A, Lee SK, Keasling JD. Intracellular cellobiose metabolism and its applications in lignocellulose-based biorefineries. BIORESOURCE TECHNOLOGY 2017; 239:496-506. [PMID: 28535986 DOI: 10.1016/j.biortech.2017.05.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 04/27/2017] [Accepted: 05/01/2017] [Indexed: 05/28/2023]
Abstract
Complete hydrolysis of cellulose has been a key characteristic of biomass technology because of the limitation of industrial production hosts to use cellodextrin, the partial hydrolysis product of cellulose. Cellobiose, a β-1,4-linked glucose dimer, is a major cellodextrin of the enzymatic hydrolysis (via endoglucanase and exoglucanase) of cellulose. Conversion of cellobiose to glucose is executed by β-glucosidase. The complete extracellular hydrolysis of celluloses has several critical barriers in biomass technology. An alternative bioengineering strategy to make the bioprocessing less challenging is to engineer microbes with the abilities to hydrolyze and assimilate the cellulosic-hydrolysate cellodextrin. Microorganisms engineered to metabolize cellobiose rather than the monomeric glucose can provide several advantages for lignocellulose-based biorefineries. This review describes the recent advances and challenges in engineering efficient intracellular cellobiose metabolism in industrial hosts. This review also describes the limitations of and future prospectives in engineering intracellular cellobiose metabolism.
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Affiliation(s)
- Vinuselvi Parisutham
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Sathesh-Prabu Chandran
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Aindrila Mukhopadhyay
- Joint BioEnergy Institute, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Sung Kuk Lee
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea; School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea.
| | - Jay D Keasling
- Joint BioEnergy Institute, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Department of Chemical and Biomolecular Engineering & Department of Bioengineering, UC Berkeley, Berkeley, CA 94720, USA; Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, KogleAllé, DK2970 Hørsholm, Denmark; Synthetic Biology Engineering Research Center (Synberc), Berkeley, CA 94720, USA
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93
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Cellobiose Consumption Uncouples Extracellular Glucose Sensing and Glucose Metabolism in Saccharomyces cerevisiae. mBio 2017; 8:mBio.00855-17. [PMID: 28790206 PMCID: PMC5550752 DOI: 10.1128/mbio.00855-17] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Glycolysis is central to energy metabolism in most organisms and is highly regulated to enable optimal growth. In the yeast Saccharomyces cerevisiae, feedback mechanisms that control flux through glycolysis span transcriptional control to metabolite levels in the cell. Using a cellobiose consumption pathway, we decoupled glucose sensing from carbon utilization, revealing new modular layers of control that induce ATP consumption to drive rapid carbon fermentation. Alterations of the beta subunit of phosphofructokinase-1 (PFK2), H+-plasma membrane ATPase (PMA1), and glucose sensors (SNF3 and RGT2) revealed the importance of coupling extracellular glucose sensing to manage ATP levels in the cell. Controlling the upper bound of cellular ATP levels may be a general mechanism used to regulate energy levels in cells, via a regulatory network that can be uncoupled from ATP concentrations under perceived starvation conditions. Living cells are fine-tuned through evolution to thrive in their native environments. Genome alterations to create organisms for specific biotechnological applications may result in unexpected and undesired phenotypes. We used a minimal synthetic biological system in the yeast Saccharomyces cerevisiae as a platform to reveal novel connections between carbon sensing, starvation conditions, and energy homeostasis.
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94
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Jansen MLA, Bracher JM, Papapetridis I, Verhoeven MD, de Bruijn H, de Waal PP, van Maris AJA, Klaassen P, Pronk JT. Saccharomyces cerevisiae strains for second-generation ethanol production: from academic exploration to industrial implementation. FEMS Yeast Res 2017; 17:3868933. [PMID: 28899031 PMCID: PMC5812533 DOI: 10.1093/femsyr/fox044] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 06/15/2017] [Indexed: 11/18/2022] Open
Abstract
The recent start-up of several full-scale 'second generation' ethanol plants marks a major milestone in the development of Saccharomyces cerevisiae strains for fermentation of lignocellulosic hydrolysates of agricultural residues and energy crops. After a discussion of the challenges that these novel industrial contexts impose on yeast strains, this minireview describes key metabolic engineering strategies that have been developed to address these challenges. Additionally, it outlines how proof-of-concept studies, often developed in academic settings, can be used for the development of robust strain platforms that meet the requirements for industrial application. Fermentation performance of current engineered industrial S. cerevisiae strains is no longer a bottleneck in efforts to achieve the projected outputs of the first large-scale second-generation ethanol plants. Academic and industrial yeast research will continue to strengthen the economic value position of second-generation ethanol production by further improving fermentation kinetics, product yield and cellular robustness under process conditions.
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Affiliation(s)
- Mickel L. A. Jansen
- DSM Biotechnology Centre, Alexander Fleminglaan 1, 2613 AX Delft, The
Netherlands
| | - Jasmine M. Bracher
- Department of Biotechnology, Delft University of Technology, Van der Maasweg
9, 2629 HZ Delft, The Netherlands
| | - Ioannis Papapetridis
- Department of Biotechnology, Delft University of Technology, Van der Maasweg
9, 2629 HZ Delft, The Netherlands
| | - Maarten D. Verhoeven
- Department of Biotechnology, Delft University of Technology, Van der Maasweg
9, 2629 HZ Delft, The Netherlands
| | - Hans de Bruijn
- DSM Biotechnology Centre, Alexander Fleminglaan 1, 2613 AX Delft, The
Netherlands
| | - Paul P. de Waal
- DSM Biotechnology Centre, Alexander Fleminglaan 1, 2613 AX Delft, The
Netherlands
| | - Antonius J. A. van Maris
- Department of Biotechnology, Delft University of Technology, Van der Maasweg
9, 2629 HZ Delft, The Netherlands
| | - Paul Klaassen
- DSM Biotechnology Centre, Alexander Fleminglaan 1, 2613 AX 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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95
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Abstract
To respond to the changing environment, cells must be able to sense external conditions. This is important for many processes including growth, mating, the expression of virulence factors, and several other regulatory effects. Nutrient sensing at the plasma membrane is mediated by different classes of membrane proteins that activate downstream signaling pathways: nontransporting receptors, transceptors, classical and nonclassical G-protein-coupled receptors, and the newly defined extracellular mucin receptors. Nontransporting receptors have the same structure as transport proteins, but have lost the capacity to transport while gaining a receptor function. Transceptors are transporters that also function as a receptor, because they can rapidly activate downstream signaling pathways. In this review, we focus on these four types of fungal membrane proteins. We mainly discuss the sensing mechanisms relating to sugars, ammonium, and amino acids. Mechanisms for other nutrients, such as phosphate and sulfate, are discussed briefly. Because the model yeast Saccharomyces cerevisiae has been the most studied, especially regarding these nutrient-sensing systems, each subsection will commence with what is known in this species.
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96
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Wickramasinghe GHIM, Rathnayake PPAMSI, Chandrasekharan NV, Weerasinghe MSS, Wijesundera RLC, Wijesundera WSS. Trichoderma virens β-glucosidase I (BGLI) gene; expression in Saccharomyces cerevisiae including docking and molecular dynamics studies. BMC Microbiol 2017; 17:137. [PMID: 28637443 PMCID: PMC5480148 DOI: 10.1186/s12866-017-1049-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 06/14/2017] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Cellulose, a linear polymer of β 1-4, linked glucose, is the most abundant renewable fraction of plant biomass (lignocellulose). It is synergistically converted to glucose by endoglucanase (EG) cellobiohydrolase (CBH) and β-glucosidase (BGL) of the cellulase complex. BGL plays a major role in the conversion of randomly cleaved cellooligosaccharides into glucose. As it is well known, Saccharomyces cerevisiae can efficiently convert glucose into ethanol under anaerobic conditions. Therefore, S.cerevisiae was genetically modified with the objective of heterologous extracellular expression of the BGLI gene of Trichoderma virens making it capable of utilizing cellobiose to produce ethanol. RESULTS The cDNA and a genomic sequence of the BGLI gene of Trichoderma virens was cloned in the yeast expression vector pGAPZα and separately transformed to Saccharomyces cerevisiae. The size of the BGLI cDNA clone was 1363 bp and the genomic DNA clone contained an additional 76 bp single intron following the first exon. The gene was 90% similar to the DNA sequence and 99% similar to the deduced amino acid sequence of 1,4-β-D-glucosidase of T. atroviride (AC237343.1). The BGLI activity expressed by the recombinant genomic clone was 3.4 times greater (1.7 x 10-3 IU ml-1) than that observed for the cDNA clone (5 x 10-4 IU ml-1). Furthermore, the activity was similar to the activity of locally isolated Trichoderma virens (1.5 x 10-3 IU ml-1). The estimated size of the protein was 52 kDA. In fermentation studies, the maximum ethanol production by the genomic and the cDNA clones were 0.36 g and 0.06 g /g of cellobiose respectively. Molecular docking results indicated that the bare protein and cellobiose-protein complex behave in a similar manner with considerable stability in aqueous medium. The deduced binding site and the binding affinity of the constructed homology model appeared to be reasonable. Moreover, it was identified that the five hydrogen bonds formed between the amino acid residues of BGLI and cellobiose are mainly involved in the integrity of enzyme-substrate association. CONCLUSIONS The BGLI activity was remarkably higher in the genomic DNA clone compared to the cDNA clone. Cellobiose was successfully fermented into ethanol by the recombinant S.cerevisiae genomic DNA clone. It has the potential to be used in the industrial production of ethanol as it is capable of simultaneous saccharification and fermentation of cellobiose. Homology modeling, docking studies and molecular dynamics simulation studies will provide a realistic model for further studies in the modification of active site residues which could be followed by mutation studies to improve the catalytic action of BGLI.
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97
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A fungal transcription factor essential for starch degradation affects integration of carbon and nitrogen metabolism. PLoS Genet 2017; 13:e1006737. [PMID: 28467421 PMCID: PMC5435353 DOI: 10.1371/journal.pgen.1006737] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 05/17/2017] [Accepted: 04/05/2017] [Indexed: 12/19/2022] Open
Abstract
In Neurospora crassa, the transcription factor COL-26 functions as a regulator of glucose signaling and metabolism. Its loss leads to resistance to carbon catabolite repression. Here, we report that COL-26 is necessary for the expression of amylolytic genes in N. crassa and is required for the utilization of maltose and starch. Additionally, the Δcol-26 mutant shows growth defects on preferred carbon sources, such as glucose, an effect that was alleviated if glutamine replaced ammonium as the primary nitrogen source. This rescue did not occur when maltose was used as a sole carbon source. Transcriptome and metabolic analyses of the Δcol-26 mutant relative to its wild type parental strain revealed that amino acid and nitrogen metabolism, the TCA cycle and GABA shunt were adversely affected. Phylogenetic analysis showed a single col-26 homolog in Sordariales, Ophilostomatales, and the Magnaporthales, but an expanded number of col-26 homologs in other filamentous fungal species. Deletion of the closest homolog of col-26 in Trichoderma reesei, bglR, resulted in a mutant with similar preferred carbon source growth deficiency, and which was alleviated if glutamine was the sole nitrogen source, suggesting conservation of COL-26 and BglR function. Our finding provides novel insight into the role of COL-26 for utilization of starch and in integrating carbon and nitrogen metabolism for balanced metabolic activities for optimal carbon and nitrogen distribution. In nature, filamentous fungi sense nutrient availability in the surrounding environment and adjust their metabolism for optimal utilization, growth and reproduction. Carbon and nitrogen are two of major elements required for life. Within cells, signals from carbon and nitrogen catabolism are integrated, resulting in balanced metabolic activities for optimal carbon and nitrogen distribution. However, coordination of carbon and nitrogen metabolism is often missed in studies that are based on comparisons between single carbon or nitrogen sources. In this study, we performed systematic transcriptional profiling of Neurospora crassa on different components of starch and identified the transcription factor COL-26 to be an essential regulator for starch utilization and needed for coordinating carbon and nitrogen regulation and metabolism. Proteins with sequence similar to COL-26 widely exist among ascomycete fungi. Here we provide experimental evidence for shared function of a col-26 ortholog in Trichoderma reesei. Our finding provides novel insight into how the regulation of carbon and nitrogen metabolism can be integrated in filamentous fungi by the function of COL-26 and which may aid in the rational design of fungal strains for industrial purposes.
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98
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Waters JC, Nixon A, Dwyer M, Biffinger JC, Lee K. Developing elite Neurospora crassa strains for cellulosic ethanol production using fungal breeding. J Ind Microbiol Biotechnol 2017; 44:1137-1144. [PMID: 28429154 PMCID: PMC5511601 DOI: 10.1007/s10295-017-1941-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 03/27/2017] [Indexed: 01/14/2023]
Abstract
The demand for renewable and sustainable energy has generated considerable interest in the conversion of cellulosic biomass into liquid fuels such as ethanol using a filamentous fungus. While attempts have been made to study cellulose metabolism through the use of knock-out mutants, there have been no systematic effort to characterize natural variation for cellulose metabolism in ecotypes adapted to different habitats. Here, we characterized natural variation in saccharification of cellulose and fermentation in 73 ecotypes and 89 laboratory strains of the model fungus Neurospora crassa. We observed significant variation in both traits among natural and laboratory generated populations, with some elite strains performing better than the reference strain. In the F1 population N345, 15% of the population outperformed both parents with the top performing strain having 10% improvement in ethanol production. These results suggest that natural alleles can be exploited through fungal breeding for developing elite industrial strains for bioethanol production.
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Affiliation(s)
- Joshua C Waters
- Department of Biology, Rutgers, The State University of New Jersey, Camden, NJ, 08103, USA
| | - Andrew Nixon
- Center for Computational and Integrative Biology, Rutgers, The State University of New Jersey, Camden, NJ, 08103, USA
| | - Morgan Dwyer
- Department of Biology, Rutgers, The State University of New Jersey, Camden, NJ, 08103, USA
| | - Justin C Biffinger
- Chemistry Department, US Naval Research Laboratory, Washington D.C., 20375, USA
| | - Kwangwon Lee
- Department of Biology, Rutgers, The State University of New Jersey, Camden, NJ, 08103, USA.
- Center for Computational and Integrative Biology, Rutgers, The State University of New Jersey, Camden, NJ, 08103, USA.
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99
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Lee WH, Jin YS. Improved ethanol production by engineered Saccharomyces cerevisiae expressing a mutated cellobiose transporter during simultaneous saccharification and fermentation. J Biotechnol 2017; 245:1-8. [DOI: 10.1016/j.jbiotec.2017.01.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 12/30/2016] [Accepted: 01/27/2017] [Indexed: 10/20/2022]
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100
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Kim SJ, Kim JW, Lee YG, Park YC, Seo JH. Metabolic engineering of Saccharomyces cerevisiae for 2,3-butanediol production. Appl Microbiol Biotechnol 2017; 101:2241-2250. [DOI: 10.1007/s00253-017-8172-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 01/31/2017] [Accepted: 02/02/2017] [Indexed: 01/04/2023]
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