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Pinto CM, Schnepper AP, Trindade PHE, Cardoso LH, Fioretto MN, Justulin LA, Zanelli CF, Valente GT. The joint action of yeast eisosomes and membraneless organelles in response to ethanol stress. Heliyon 2024; 10:e31561. [PMID: 38818138 PMCID: PMC11137566 DOI: 10.1016/j.heliyon.2024.e31561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 05/13/2024] [Accepted: 05/17/2024] [Indexed: 06/01/2024] Open
Abstract
Elevated ethanol concentrations in yeast affect the plasma membrane. The plasma membrane in yeast has many lipid-protein complexes, such as Pma1 (MCP), Can1 (MCC), and the eisosome complex. We investigated the response of eisosomes, MCPs, and membraneless structures to ethanol stress. We found a correlation between ethanol stress and proton flux with quick acidification of the medium. Moreover, ethanol stress influences the symporter expression in stressed cells. We also suggest that acute stress from ethanol leads to increases in eisosome size and SG number: we hypothesized that eisosomes may protect APC symporters and accumulate an mRNA decay protein in ethanol-stressed cells. Our findings suggest that the joint action of these factors may provide a protective effect on cells under ethanol stress.
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Affiliation(s)
- Camila Moreira Pinto
- Laboratory of Applied Biotechnology. São Paulo State University (UNESP). Botucatu, Brazil
| | | | - Pedro Henrique Esteves Trindade
- Department of Population Health and Pathobiology College of Veterinary Medicine, North Carolina State University (NCSU) Raleigh, USA
| | - Luiz Henrique Cardoso
- Laboratory of Applied Biotechnology. São Paulo State University (UNESP). Botucatu, Brazil
| | - Matheus Naia Fioretto
- Department of Structural and Functional Biology, Institute of Biosciences. São Paulo State University (UNESP). Botucatu, Brazil
| | - Luís Antônio Justulin
- Department of Structural and Functional Biology, Institute of Biosciences. São Paulo State University (UNESP). Botucatu, Brazil
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Co-expression of an isopropanol synthetic operon and eGFP to monitor the robustness of Cupriavidus necator during isopropanol production. Enzyme Microb Technol 2022; 161:110114. [DOI: 10.1016/j.enzmictec.2022.110114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 07/19/2022] [Accepted: 08/16/2022] [Indexed: 11/19/2022]
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3
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Zhang W, Shao W, Zhang A. Isobutanol tolerance and production of Saccharomyces cerevisiae can be improved by engineering its TATA-binding protein Spt15. Lett Appl Microbiol 2021; 73:694-707. [PMID: 34418130 DOI: 10.1111/lam.13555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 08/10/2021] [Accepted: 08/12/2021] [Indexed: 11/26/2022]
Abstract
Low isobutanol tolerance of Saccharomyces cerevisiae limits its application in isobutanol fermentation. Here, we used global transcription machinery engineering to screen mutants with higher isobutanol tolerance and elevated isobutanol titres. TATA-binding protein Spt15 was used as the target of global transcription machinery engineering for improvement of such complex phenotypes. A random mutagenesis library of S. cerevisiae TATA-binding protein Spt15 was constructed and subjected to screening under isobutanol stress. A mutant strain (denoted as spt15-3) with improved isobutanol tolerance was identified. There were three mutations of Spt15 in strain spt15-3, including deletion of A at position -132 nt upstream of initiation codon, insertion of G at position -65 nt upstream of initiation codon and a synonymous mutation at position 315 nt (T → C) downstream of initiation codon. We then metabolically engineered isobutanol synthesis in strains harbouring plasmids YCplac22 containing these Spt15 mutations. Delta integration was used to overexpress ILV3 gene, and 2μ plasmids carrying PGK1p-ILV2 and PGK1p-ARO10 were used to overexpress ILV2 and ARO10 genes. After 24-h micro-aerobic fermentation, Engi-3 produced 0·556 g l-1 isobutanol, which was 404% and 25·3% greater than isobutanol produced by control Engi-1 and engineered Engi-2, respectively. After 28 h, Engi-4 produced 0·459 g l-1 isobutanol, which was 315% and 3·2% greater than isobutanol produced Engi-1 and Engi-2, respectively. RNA-Seq-based transcriptome analysis shows that mutations of Spt15 in strain spt15-3 increased the expression of SPT15. Meanwhile, compared with strain Engi-3, the spt15-3 mutation downregulated the expression of genes involved in the TCA cycle and glyoxylic acid cycle, but increased the expression of genes related to cell stability. This work demonstrates that isobutanol tolerance and production of S. cerevisiae can be improved by engineering its TATA-binding protein Spt15. This study clarified the molecular mechanisms regulating isobutanol production and tolerance in S. cerevisiae.
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Affiliation(s)
- W Zhang
- School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin, China
| | - W Shao
- School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin, China
| | - A Zhang
- School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin, China
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Detection of Red Wine Faults over Time with Flash Profiling and the Electronic Tongue. BEVERAGES 2021. [DOI: 10.3390/beverages7030052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Wine faults, often caused by spoilage microorganisms, are considered negative sensory attributes, and may result in substantial economic losses. The objective of this study was to use the electronic tongue (e-tongue) and flash sensory profiling (FP) to evaluate changes in red wine over time due to the presence of different spoilage microorganisms. Merlot wine was inoculated with one of the following microorganisms: Brettanomyces bruxellensis, Lactobacillus brevis, Pediococcus parvulus, or Acetobacter pasteurianus. These wines were analyzed weekly until Day 42 using the e-tongue and FP, with microbial plate counts. Over time, both FP and e-tongue differentiated the wines. The e-tongue showed a low discrimination among microorganisms up to Day 14 of storage. However, at Day 21 and continuing to Day 42, the e-tongue discriminated among the samples with a discrimination index of 91. From the sensory FP data, assessors discriminated among the wines starting at Day 28. Non-spoilage terms were used to describe the wines at significantly higher frequency for all time points until Day 42, at which point the use of spoilage terms was significantly higher (p < 0.05). These results suggest that application of these novel techniques may be the key to detecting and limiting financial losses associated with wine faults.
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Ethanol addition elevates cell respiratory activity and causes overproduction of natural yellow pigments in submerged fermentation of Monascus purpureus. Lebensm Wiss Technol 2021. [DOI: 10.1016/j.lwt.2020.110534] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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6
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Calumba KF, Reyes V, Bonilla F, Villasmil E, Sathivel S. Ale beer containing free and immobilized Lactobacillus brevis, a potential delivery system for probiotics. FOOD PRODUCTION, PROCESSING AND NUTRITION 2021. [DOI: 10.1186/s43014-021-00051-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Abstract
Probiotics in ale beer may be attractive to health-conscious consumers. However, beer conditions may decrease probiotic viability. Powder produced from durian (Durio zibethinus) rind, a by-product that is currently unutilized, can be used for the immobilization of probiotics. MRS medium was incubated with Lactobacillus brevis and periodically sampled to obtain the growth curve. Ale beer with free L. brevis and cells immobilized in durian rind powder was produced and separately assessed during storage at 21 °C for 24 days. The physico-chemical parameters of both beers did not differ significantly. Durian rind powder conferred protection up to 12 days of storage with the immobilized cells in the beer having a significantly higher count than the free cells, which can be due to the acid detergent fiber content (19.67%). Free and immobilized cells remained viable with counts of 4.89 and 5.00 log CFU/mL of beer, respectively, at the end of the storage period. Both treatments had approximate counts of 5 log CFU/mL after 120 min in simulated gastric and intestinal fluids. The predominant bacterial species present at the end of storage were L. brevis and L. farciminis. This study suggests that ale beer could be a potential delivery system for free and immobilized probiotic bacteria. This is one of the few studies demonstrating the use of probiotic lactic acid bacteria in beer brewing.
Graphical abstract
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Gao Y, Zhou X, Zhang MM, Liu YJ, Guo XP, Lei CR, Li WJ, Lu D. Response characteristics of the membrane integrity and physiological activities of the mutant strain Y217 under exogenous butanol stress. Appl Microbiol Biotechnol 2021; 105:2455-2472. [PMID: 33606076 DOI: 10.1007/s00253-021-11174-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 01/30/2021] [Accepted: 02/10/2021] [Indexed: 01/05/2023]
Abstract
Butanol inhibits bacterial activity by destroying the cell membrane of Clostridium acetobutylicum strains and altering functionality. Butanol toxicity also results in destruction of the phosphoenolpyruvate-carbohydrate phosphotransferase system (PTS), thereby preventing glucose transport and phosphorylation and inhibiting transmembrane transport and assimilation of sugars, amino acids, and other nutrients. In this study, based on the addition of exogenous butanol, the tangible macro indicators of changes in the carbon ion beam irradiation-mutant Y217 morphology were observed using scanning electron microscopy (SEM). The mutant has lower microbial adhesion to hydrocarbon (MATH) value than C. acetobutylicum ATCC 824 strain. FDA fluorescence intensity and conductivity studies demonstrated the intrinsically low membrane permeability of the mutant membrane, with membrane potential remaining relatively stable. Monounsaturated FAs (MUFAs) accounted for 35.17% of the mutant membrane, and the saturated fatty acids (SFA)/unsaturated fatty acids (UFA) ratio in the mutant cell membrane was 1.65. In addition, we conducted DNA-level analysis of the mutant strain Y217. Expectedly, through screening, we found gene mutant sites encoding membrane-related functions in the mutant, including ATP-binding cassette (ABC) transporter-related genes, predicted membrane proteins, and the PTS transport system. It is noteworthy that an unreported predicted membrane protein (CAC 3309) may be related to changes in mutant cell membrane properties. KEY POINTS: • Mutant Y217 exhibited better membrane integrity and permeability. • Mutant Y217 was more resistant to butanol toxicity. • Some membrane-related genes of mutant Y217 were mutated.
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Affiliation(s)
- Yue Gao
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000, China.,University of Chinese Academy of Sciences, Chinese Academy of Science, Beijing, 100049, China
| | - Xiang Zhou
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000, China.,University of Chinese Academy of Sciences, Chinese Academy of Science, Beijing, 100049, China
| | - Miao-Miao Zhang
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000, China.,University of Chinese Academy of Sciences, Chinese Academy of Science, Beijing, 100049, China.,Gansu Key Laboratory of Microbial Resources Exploitation and Application, Lanzhou, 730070, China
| | - Ya-Jun Liu
- University of Chinese Academy of Sciences, Chinese Academy of Science, Beijing, 100049, China.,Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
| | - Xiao-Peng Guo
- School of Life Science and Engineering, Lanzhou University of Technology, Lanzhou, China
| | - Cai-Rong Lei
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000, China.,University of Chinese Academy of Sciences, Chinese Academy of Science, Beijing, 100049, China
| | - Wen-Jian Li
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000, China.,University of Chinese Academy of Sciences, Chinese Academy of Science, Beijing, 100049, China.,Gansu Key Laboratory of Microbial Resources Exploitation and Application, Lanzhou, 730070, China
| | - Dong Lu
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000, China. .,University of Chinese Academy of Sciences, Chinese Academy of Science, Beijing, 100049, China. .,Gansu Key Laboratory of Microbial Resources Exploitation and Application, Lanzhou, 730070, China.
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8
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Yao S, Hao L, Zhou R, Jin Y, Huang J, Wu C. Co-culture with Tetragenococcus halophilus improved the ethanol tolerance of Zygosaccharomyces rouxii by maintaining cell surface properties. Food Microbiol 2021; 97:103750. [PMID: 33653523 DOI: 10.1016/j.fm.2021.103750] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 12/31/2020] [Accepted: 01/18/2021] [Indexed: 02/08/2023]
Abstract
The accumulation of ethanol has a negative effect on the viability and fermentation performance of microorganisms during the production of fermented foods because of its toxicity. In this study, we investigated the effect of co-culture with Tetragenococcus halophilus on ethanol stress resistance of Zygosaccharomyces rouxii. The result showed that co-culture with T. halophilus promoted cell survival of Z. rouxii under ethanol stress, and the tolerance improved with increasing co-culture time when ethanol content was 8%. Physiological analysis showed that the co-cultured Z. rouxii cells maintained higher intracellular content of trehalose and amino acids including tyrosine, tryptophan, arginine and proline after 8% ethanol stress for 90 min. The membrane integrity analysis and biophysical analysis of the cell surface indicated that the presence of ethanol resulted in cell membrane damage and changes of Young's modulus value and roughness of cell surface. While the co-cultured Z. rouxii cells exhibited better membrane integrity, stiffer and smoother cell surface than single-cultured cells under ethanol stress. As for transcriptomic analyses, the genes involved in unsaturated fatty acid biosynthesis, trehalose biosynthesis, various types of N-glycan biosynthesis, inositol phosphate metabolism, MAPK signaling pathway and tight junction had higher expression in co-cultured Z. rouxii cells with down-regulation of majority of gene expression after stress. And these genes may function in the improvement of ethanol tolerance of Z. rouxii in co-culture.
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Affiliation(s)
- Shangjie Yao
- College of Biomass Science and Engineering, Sichuan University, Chengdu, 610065, China; Key Laboratory of Leather Chemistry and Engineering, Ministry of Education, Sichuan University, Chengdu, 610065, China
| | - Liying Hao
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Rongqing Zhou
- College of Biomass Science and Engineering, Sichuan University, Chengdu, 610065, China; Key Laboratory of Leather Chemistry and Engineering, Ministry of Education, Sichuan University, Chengdu, 610065, China
| | - Yao Jin
- College of Biomass Science and Engineering, Sichuan University, Chengdu, 610065, China; Key Laboratory of Leather Chemistry and Engineering, Ministry of Education, Sichuan University, Chengdu, 610065, China
| | - Jun Huang
- College of Biomass Science and Engineering, Sichuan University, Chengdu, 610065, China; Key Laboratory of Leather Chemistry and Engineering, Ministry of Education, Sichuan University, Chengdu, 610065, China
| | - Chongde Wu
- College of Biomass Science and Engineering, Sichuan University, Chengdu, 610065, China; Key Laboratory of Leather Chemistry and Engineering, Ministry of Education, Sichuan University, Chengdu, 610065, China.
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9
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Abstract
Microbial cells that live in the same community can exist in different physiological and morphological states that change as a function of spatiotemporal variations in environmental conditions. This phenomenon is commonly known as phenotypic heterogeneity and/or diversity. Measuring this plethora of cellular expressions is needed to better understand and manage microbial processes. However, most tools to study phenotypic diversity only average the behavior of the sampled community. In this work, we present a way to quantify the phenotypic diversity of microbial samples by inferring the (bio)molecular profile of its constituent cells using Raman spectroscopy. We demonstrate how this tool can be used to quantify the phenotypic diversity that arises after the exposure of microbes to stress. Raman spectroscopy holds potential for the detection of stressed cells in bioproduction. Microbial cells experience physiological changes due to environmental change, such as pH and temperature, the release of bactericidal agents, or nutrient limitation. This has been shown to affect community assembly and physiological processes (e.g., stress tolerance, virulence, or cellular metabolic activity). Metabolic stress is typically quantified by measuring community phenotypic properties such as biomass growth, reactive oxygen species, or cell permeability. However, bulk community measurements do not take into account single-cell phenotypic diversity, which is important for a better understanding and the subsequent management of microbial populations. Raman spectroscopy is a nondestructive alternative that provides detailed information on the biochemical makeup of each individual cell. Here, we introduce a method for describing single-cell phenotypic diversity using the Hill diversity framework of Raman spectra. Using the biomolecular profile of individual cells, we obtained a metric to compare cellular states and used it to study stress-induced changes. First, in two Escherichia coli populations either treated with ethanol or nontreated and then in two Saccharomyces cerevisiae subpopulations with either high or low expression of a stress reporter. In both cases, we were able to quantify single-cell phenotypic diversity and to discriminate metabolically stressed cells using a clustering algorithm. We also described how the lipid, protein, and nucleic acid compositions changed after the exposure to the stressor using information from the Raman spectra. Our results show that Raman spectroscopy delivers the necessary resolution to quantify phenotypic diversity within individual cells and that this information can be used to study stress-driven metabolic diversity in microbial populations. IMPORTANCE Microbial cells that live in the same community can exist in different physiological and morphological states that change as a function of spatiotemporal variations in environmental conditions. This phenomenon is commonly known as phenotypic heterogeneity and/or diversity. Measuring this plethora of cellular expressions is needed to better understand and manage microbial processes. However, most tools to study phenotypic diversity only average the behavior of the sampled community. In this work, we present a way to quantify the phenotypic diversity of microbial samples by inferring the (bio)molecular profile of its constituent cells using Raman spectroscopy. We demonstrate how this tool can be used to quantify the phenotypic diversity that arises after the exposure of microbes to stress. Raman spectroscopy holds potential for the detection of stressed cells in bioproduction.
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Zhang J, Zhang X, Mao Y, Jin B, Guo Y, Wang Z, Chen T. Substrate profiling and tolerance testing of Halomonas TD01 suggest its potential application in sustainable manufacturing of chemicals. J Biotechnol 2020; 316:1-5. [PMID: 32311394 DOI: 10.1016/j.jbiotec.2020.04.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 04/10/2020] [Accepted: 04/13/2020] [Indexed: 01/19/2023]
Abstract
Halomonas TD01, which can grow under non-sterile and continuous processes at high pH and high salt concentrations, is a robust platform for PHA production from glucose. For extending other low-cost sustainable substrates and increasing the potential application in other value-added products, a better understanding of substrates utilization and chemicals tolerance is necessary. In this study, the substrate profiling of TD01 was analyzed via Biolog. Phenotype microarray results demonstrated that TD01 has a wide-ranging substrate spectrum and can utilize 140 of the 190 test compounds. Some cheap, abundant carbon sources, such as sodium acetate, glycerol, ethanol and lactate can well support the growth of TD01 in shake-flask, and are therefore suggested to be its alternative low-cost substrates for chemicals production in future. Furthermore, the tolerance of TD01 to various chemicals was tested. The results showed that the tolerability of TD01 to high concentrations of organic acid salts is prominent. When adding 75 g/L sodium acetate, 100 g/L succinic acid and 100 g/L itaconic acid in the medium, the growth rate reduced 56.14%, 52.63% and 47.37%, respectively. All these results highlight TD01 as a promising, next generation industrial workhorse in chemicals biomanufacturing from cheap organic acid salts.
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Affiliation(s)
- Jing Zhang
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering of Ministry of Education, SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Xin Zhang
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering of Ministry of Education, SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Yufeng Mao
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Biao Jin
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering of Ministry of Education, SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Yanmei Guo
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Zhiwen Wang
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering of Ministry of Education, SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Tao Chen
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering of Ministry of Education, SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China.
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11
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Westman JO, Wang R, Novy V, Franzén CJ. Sustaining fermentation in high-gravity ethanol production by feeding yeast to a temperature-profiled multifeed simultaneous saccharification and co-fermentation of wheat straw. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:213. [PMID: 28919926 PMCID: PMC5596858 DOI: 10.1186/s13068-017-0893-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 08/24/2017] [Indexed: 05/17/2023]
Abstract
BACKGROUND Considerable progress is being made in ethanol production from lignocellulosic feedstocks by fermentation, but negative effects of inhibitors on fermenting microorganisms are still challenging. Feeding preadapted cells has shown positive effects by sustaining fermentation in high-gravity simultaneous saccharification and co-fermentation (SSCF). Loss of cell viability has been reported in several SSCF studies on different substrates and seems to be the main reason for the declining ethanol production toward the end of the process. Here, we investigate how the combination of yeast preadaptation and feeding, cell flocculation, and temperature reduction improves the cell viability in SSCF of steam pretreated wheat straw. RESULTS More than 50% cell viability was lost during the first 24 h of high-gravity SSCF. No beneficial effects of adding selected nutrients were observed in shake flask SSCF. Ethanol concentrations greater than 50 g L-1 led to significant loss of viability and prevented further fermentation in SSCF. The benefits of feeding preadapted yeast cells were marginal at later stages of SSCF. Yeast flocculation did not improve the viability but simplified cell harvest and improved the feasibility of the cell feeding strategy in demo scale. Cultivation at 30 °C instead of 35 °C increased cell survival significantly on solid media containing ethanol and inhibitors. Similarly, in multifeed SSCF, cells maintained the viability and fermentation capacity when the temperature was reduced from 35 to 30 °C during the process, but hydrolysis yields were compromised. By combining the yeast feeding and temperature change, an ethanol concentration of 65 g L-1, equivalent to 70% of the theoretical yield, was obtained in multifeed SSCF on pretreated wheat straw. In demo scale, the process with flocculating yeast and temperature profile resulted in 5% (w/w) ethanol, equivalent to 53% of the theoretical yield. CONCLUSIONS Multifeed SSCF was further developed by means of a flocculating yeast and a temperature-reduction profile. Ethanol toxicity is intensified in the presence of lignocellulosic inhibitors at temperatures that are beneficial to hydrolysis in high-gravity SSCF. The counteracting effects of temperature on cell viability and hydrolysis call for more tolerant microorganisms, enzyme systems with lower temperature optimum, or full optimization of the multifeed strategy with temperature profile.
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Affiliation(s)
- Johan O. Westman
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
- Present Address: Chr. Hansen A/S, Bøge Allé 10-12, 2970 Hørsholm, Denmark
| | - Ruifei Wang
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Vera Novy
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, Graz, Austria
- Present Address: Forest Products Biotechnology, Faculty of Forestry, University of British Columbia, Vancouver, BC V6T1Z4 Canada
| | - Carl Johan Franzén
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
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12
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Random sample consensus combined with partial least squares regression (RANSAC-PLS) for microbial metabolomics data mining and phenotype improvement. J Biosci Bioeng 2016; 122:168-75. [DOI: 10.1016/j.jbiosc.2016.01.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 01/12/2016] [Accepted: 01/12/2016] [Indexed: 11/18/2022]
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13
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Vinay-Lara E, Wang S, Bai L, Phrommao E, Broadbent JR, Steele JL. Lactobacillus casei as a biocatalyst for biofuel production. J Ind Microbiol Biotechnol 2016; 43:1205-13. [PMID: 27312380 DOI: 10.1007/s10295-016-1797-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 06/04/2016] [Indexed: 11/28/2022]
Abstract
Microbial fermentation of sugars from plant biomass to alcohols represents an alternative to petroleum-based fuels. The optimal biocatalyst for such fermentations needs to overcome hurdles such as high concentrations of alcohols and toxic compounds. Lactic acid bacteria, especially lactobacilli, have high innate alcohol tolerance and are remarkably adaptive to harsh environments. This study assessed the potential of five Lactobacillus casei strains as biocatalysts for alcohol production. L. casei 12A was selected based upon its innate alcohol tolerance, high transformation efficiency and ability to utilize plant-derived carbohydrates. A 12A derivative engineered to produce ethanol (L. casei E1) was compared to two other bacterial biocatalysts. Maximal growth rate, maximal optical density and ethanol production were determined under conditions similar to those present during alcohol production from lignocellulosic feedstocks. L. casei E1 exhibited higher innate alcohol tolerance, better growth in the presence of corn stover hydrolysate stressors, and resulted in higher ethanol yields.
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Affiliation(s)
- Elena Vinay-Lara
- Department of Food Science, University of Wisconsin-Madison, 127B Babcock Hall, 1605 Linden Drive, Madison, WI, 53706, USA
| | - Song Wang
- College of Food Science, Northeast Agricultural University, Harbin, Heilongjiang, China
| | - Lina Bai
- College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Ekkarat Phrommao
- Department of Food Science, University of Wisconsin-Madison, 127B Babcock Hall, 1605 Linden Drive, Madison, WI, 53706, USA
| | - Jeff R Broadbent
- Department of Nutrition, Dietetics, and Food Sciences, Utah State University, Logan, Utah, 84322-8700, USA
| | - James L Steele
- Department of Food Science, University of Wisconsin-Madison, 127B Babcock Hall, 1605 Linden Drive, Madison, WI, 53706, USA.
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Cray JA, Stevenson A, Ball P, Bankar SB, Eleutherio ECA, Ezeji TC, Singhal RS, Thevelein JM, Timson DJ, Hallsworth JE. Chaotropicity: a key factor in product tolerance of biofuel-producing microorganisms. Curr Opin Biotechnol 2015; 33:228-59. [PMID: 25841213 DOI: 10.1016/j.copbio.2015.02.010] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 02/13/2015] [Accepted: 02/18/2015] [Indexed: 10/23/2022]
Abstract
Fermentation products can chaotropically disorder macromolecular systems and induce oxidative stress, thus inhibiting biofuel production. Recently, the chaotropic activities of ethanol, butanol and vanillin have been quantified (5.93, 37.4, 174kJ kg(-1)m(-1) respectively). Use of low temperatures and/or stabilizing (kosmotropic) substances, and other approaches, can reduce, neutralize or circumvent product-chaotropicity. However, there may be limits to the alcohol concentrations that cells can tolerate; e.g. for ethanol tolerance in the most robust Saccharomyces cerevisiae strains, these are close to both the solubility limit (<25%, w/v ethanol) and the water-activity limit of the most xerotolerant strains (0.880). Nevertheless, knowledge-based strategies to mitigate or neutralize chaotropicity could lead to major improvements in rates of product formation and yields, and also therefore in the economics of biofuel production.
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Affiliation(s)
- Jonathan A Cray
- Institute for Global Food Security, School of Biological Sciences, MBC, Queen's University Belfast, Belfast BT9 7BL, Northern Ireland, UK
| | - Andrew Stevenson
- Institute for Global Food Security, School of Biological Sciences, MBC, Queen's University Belfast, Belfast BT9 7BL, Northern Ireland, UK
| | - Philip Ball
- 18 Hillcourt Road, East Dulwich, London SE22 0PE, UK
| | - Sandip B Bankar
- Department of Chemical Engineering, College of Engineering, Bharati Vidyapeeth University, Pune-Satara Road, Pune 411043, India
| | - Elis C A Eleutherio
- Universidade Federal do Rio de Janeiro, Instituto de Quimica, Programa de Pós-graduação Bioquimica, Rio de Janeiro, RJ, Brazil
| | - Thaddeus C Ezeji
- Department of Animal Sciences and Ohio Agricultural Research and Development Center (OARDC), The Ohio State University, 305 Gerlaugh Hall, 1680 Madison Avenue, Wooster, OH 44691, USA
| | - Rekha S Singhal
- Department of Food Engineering and Technology, Institute of Chemical Technology, N.P. Marg, Matunga, Mumbai, Maharashtra 400019, India
| | - Johan M Thevelein
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven and Department of Molecular Microbiology, VIB, Kasteelpark Arenberg 31, Flanders, Leuven-Heverlee B-3001, Belgium
| | - David J Timson
- Institute for Global Food Security, School of Biological Sciences, MBC, Queen's University Belfast, Belfast BT9 7BL, Northern Ireland, UK
| | - John E Hallsworth
- Institute for Global Food Security, School of Biological Sciences, MBC, Queen's University Belfast, Belfast BT9 7BL, Northern Ireland, UK.
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Tillich UM, Wolter N, Franke P, Dühring U, Frohme M. Screening and genetic characterization of thermo-tolerant Synechocystis sp. PCC6803 strains created by adaptive evolution. BMC Biotechnol 2014; 14:66. [PMID: 25029912 PMCID: PMC4110520 DOI: 10.1186/1472-6750-14-66] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 07/10/2014] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Temperature tolerance is an important aspect for commercial scale outdoor cultivation of microalgae and cyanobacteria. While various genes are known to be related to Synechocystis sp. PCC6803's heat shock response, there is very limited published data concerning the specific genes involved in long term thermal tolerance. We have previously used random mutagenesis and adaptive evolution to generate a mixture of strains of Synechocystis sp. PCC6803 with significantly increased thermal tolerance. The genetic modifications leading to the phenotypes of the newly generated strains are the focus of this work. RESULTS We used a custom screening platform, based on 96-deepwell microplate culturing in an in house designed cultivation chamber integrated in a liquid handling robot for screening and selection; in addition we also used a more conventional system. The increased thermal tolerances of the isolated monoclonal strains were validated in larger bioreactors and their whole genomes sequenced. Comparison of the sequence information to the parental wild type identified various mutations responsible for the enhanced phenotypes. Among the affected genes identified are clpC, pnp, pyk2, sigF, nlpD, pyrR, pilJ and cya1. CONCLUSIONS The applied methods (random mutagenesis, in vivo selection, screening, validation, whole genome sequencing) were successfully applied to identify various mutations, some of which are very unlikely to have been identified by other approaches. Several of the identified mutations are found in various strains and (due to their distribution) are likely to have occurred independently. This, coupled with the relatively low number of affected genes underscores the significance of these specific mutations to convey thermal tolerance in Synechocystis.
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Affiliation(s)
- Ulrich M Tillich
- Molecular Biotechnology and Functional Genomics, Technical University of Applied Sciences Wildau, Bahnhofstraße 1, 16-2001, D-15745 Wildau, Germany
- Institute of Biology, Humboldt-University Berlin, Berlin, Germany
| | - Nick Wolter
- Molecular Biotechnology and Functional Genomics, Technical University of Applied Sciences Wildau, Bahnhofstraße 1, 16-2001, D-15745 Wildau, Germany
| | - Philipp Franke
- Molecular Biotechnology and Functional Genomics, Technical University of Applied Sciences Wildau, Bahnhofstraße 1, 16-2001, D-15745 Wildau, Germany
| | - Ulf Dühring
- Algenol Biofuels Germany GmbH, Berlin, Germany
| | - Marcus Frohme
- Molecular Biotechnology and Functional Genomics, Technical University of Applied Sciences Wildau, Bahnhofstraße 1, 16-2001, D-15745 Wildau, Germany
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Lütke-Eversloh T. Application of new metabolic engineering tools for Clostridium acetobutylicum. Appl Microbiol Biotechnol 2014; 98:5823-37. [DOI: 10.1007/s00253-014-5785-5] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 04/22/2014] [Accepted: 04/23/2014] [Indexed: 01/30/2023]
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Hennessy RC, Doohan F, Mullins E. Generating phenotypic diversity in a fungal biocatalyst to investigate alcohol stress tolerance encountered during microbial cellulosic biofuel production. PLoS One 2013; 8:e77501. [PMID: 24147009 PMCID: PMC3797763 DOI: 10.1371/journal.pone.0077501] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 09/09/2013] [Indexed: 11/18/2022] Open
Abstract
Consolidated bioprocessing (CBP) of lignocellulosic biomass offers an alternative route to renewable energy. The crop pathogen Fusarium oxysporum is a promising fungal biocatalyst because of its broad host range and innate ability to co-saccharify and ferment lignocellulose to bioethanol. A major challenge for cellulolytic CBP-enabling microbes is alcohol inhibition. This research tested the hypothesis that Agrobacterium tumefaciens--mediated transformation (ATMT) could be exploited as a tool to generate phenotypic diversity in F. oxysporum to investigate alcohol stress tolerance encountered during CBP. A random mutagenesis library of gene disruption transformants (n=1,563) was constructed and screened for alcohol tolerance in order to isolate alcohol sensitive or tolerant phenotypes. Following three rounds of screening, exposure of select transformants to 6% ethanol and 0.75% n-butanol resulted respectively in increased (≥ 11.74%) and decreased (≤ 43.01%) growth compared to the wild -type (WT). Principal component analysis (PCA) quantified the level of phenotypic diversity across the population of genetically transformed individuals and isolated candidate strains for analysis. Characterisation of one strain, Tr. 259, ascertained a reduced growth phenotype under alcohol stress relative to WT and indicated the disruption of a coding region homologous to a putative sugar transporter (FOXG_09625). Quantitative PCR (RT-PCR) showed FOXG_09625 was differentially expressed in Tr. 259 compared to WT during alcohol-induced stress (P<0.05). Phylogenetic analysis of putative sugar transporters suggests diverse functional roles in F. oxysporum and other filamentous fungi compared to yeast for which sugar transporters form part of a relatively conserved family. This study has confirmed the potential of ATMT coupled with a phenotypic screening program to select for genetic variation induced in response to alcohol stress. This research represents a first step in the investigation of alcohol tolerance in F. oxysporum and has resulted in the identification of several novel strains, which will be of benefit to future biofuel research.
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Affiliation(s)
- Rosanna C. Hennessy
- Department of Crop Science, Teagasc Research Centre, Oak Park, Carlow, Ireland
- Molecular Plant-Microbe Interactions Laboratory, School of Biology and Environmental Science, University College Dublin, Dublin, Ireland
| | - Fiona Doohan
- Molecular Plant-Microbe Interactions Laboratory, School of Biology and Environmental Science, University College Dublin, Dublin, Ireland
| | - Ewen Mullins
- Department of Crop Science, Teagasc Research Centre, Oak Park, Carlow, Ireland
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Improvement of thermostable aldehyde dehydrogenase by directed evolution for application in Synthetic Cascade Biomanufacturing. Enzyme Microb Technol 2013; 53:307-14. [PMID: 24034429 DOI: 10.1016/j.enzmictec.2013.07.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2013] [Revised: 07/06/2013] [Accepted: 07/08/2013] [Indexed: 11/22/2022]
Abstract
The aldehyde dehydrogenase from Thermoplasma acidophilum, which was previously implemented as a key enzyme in a synthetic cell-free reaction cascade for the production of alcohols, was optimized by directed evolution. Improvements have been made to enhance reaction velocity and solubility. Using a random approach followed by site-directed and saturation mutagenesis, three beneficial amino acid mutations were found after screening of ca. 20,000 variants. Mutation Y399C enhanced the protein solubility after recombinant expression in Escherichia coli 6-fold. Two further mutations, F34M and S405N, enhanced enzyme activity with the cofactor NAD(+) by a factor of eight. Impacts on enzyme stability and substrate specificity were negligible. Modeling of the enzyme structure did not reveal any direct interactions between the amino acid substitutions and residues of the active site or the enzyme's substrates. Thus, a directed evolution approach allowed for the generation of improved enzyme variants which were unlikely to be found by rational or semi-rational strategies.
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Tillich UM, Lehmann S, Schulze K, Dühring U, Frohme M. The optimal mutagen dosage to induce point-mutations in Synechocystis sp. PCC6803 and its application to promote temperature tolerance. PLoS One 2012; 7:e49467. [PMID: 23185339 PMCID: PMC3504032 DOI: 10.1371/journal.pone.0049467] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 10/09/2012] [Indexed: 01/18/2023] Open
Abstract
Random mutagenesis is a useful tool to genetically modify organisms for various purposes, such as adaptation to cultivation conditions, the induction of tolerances, or increased yield of valuable substances. This is especially attractive for systems where it is not obvious which genes require modifications. Random mutagenesis has been extensively used to modify crop plants, but even with the renewed interest in microalgae and cyanobacteria for biofuel applications, there is relatively limited current research available on the application of random mutagenesis for these organisms, especially for cyanobacteria. In the presented work we characterized the lethality and rate of non-lethal point mutations for ultraviolet radiation and methyl methanesulphonate on the model cyanobacteria Synechocystis sp. PCC6803. Based on these results an optimal dosage of 10-50 J/m(2) for UV and either 0.1 or 1 v% for MMS was determined. A Synechocystis wildtype culture was then mutagenized and selected for increased temperature tolerance in vivo. During the second round of mutagenesis the viability of the culture was monitored on a cell by cell level from the treatment of the cells up to the growth at an increased temperature. After four distinct rounds of treatment (two with each mutagen) the temperature tolerance of the strain was effectively raised by about 2°C. Coupled with an appropriate in vivo screening, the described methods should be applicable to induce a variety of desirable characteristics in various strains. Coupling random mutagenesis with high-throughput screening methods would additionally allow to select for important characteristics for biofuel production, which do not yield a higher fitness and can not be selected for in vivo, such as fatty acid concentration. In a combined approach with full genome sequencing random mutagenesis could be used to determine suitable target-genes for more focused methods.
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Affiliation(s)
- Ulrich M. Tillich
- Molecular Biotechnology and Functional Genomics, Technical University of Applied Sciences Wildau, Wildau, Germany
- Institute of Biology, Humboldt-University Berlin, Berlin, Germany
| | - Sandra Lehmann
- Molecular Biotechnology and Functional Genomics, Technical University of Applied Sciences Wildau, Wildau, Germany
| | - Katja Schulze
- Molecular Biotechnology and Functional Genomics, Technical University of Applied Sciences Wildau, Wildau, Germany
| | | | - Marcus Frohme
- Molecular Biotechnology and Functional Genomics, Technical University of Applied Sciences Wildau, Wildau, Germany
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Guterl JK, Garbe D, Carsten J, Steffler F, Sommer B, Reiße S, Philipp A, Haack M, Rühmann B, Koltermann A, Kettling U, Brück T, Sieber V. Cell-free metabolic engineering: production of chemicals by minimized reaction cascades. CHEMSUSCHEM 2012; 5:2165-2172. [PMID: 23086730 DOI: 10.1002/cssc.201200365] [Citation(s) in RCA: 174] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2012] [Indexed: 05/28/2023]
Abstract
The limited supply of fossil resources demands the development of renewable alternatives to petroleum-based products. Here, biobased higher alcohols such as isobutanol are versatile platform molecules for the synthesis of chemical commodities and fuels. Currently, their fermentation-based production is limited by the low tolerance of microbial production systems to the end products and also by the low substrate flux into cell metabolism. We developed an innovative cell-free approach, utilizing an artificial minimized glycolytic reaction cascade that only requires one single coenzyme. Using this toolbox the cell-free production of ethanol and isobutanol from glucose was achieved. We also confirmed that these streamlined cascades functioned under conditions at which microbial production would have ceased. Our system can be extended to an array of industrially-relevant molecules. Application of solvent-tolerant biocatalysts potentially allows for high product yields, which significantly simplifies downstream product recovery.
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Affiliation(s)
- Jan-Karl Guterl
- Lehrstuhl für Chemie Biogener Rohstoffe, Technische Universität München, Schulgasse 16, 94315 Straubing, Germany
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Affiliation(s)
- Jan-Karl Guterl
- Lehrstuhl für Chemie Biogener Rohstoffe; Technische Universität München; Straubing; Germany
| | - Volker Sieber
- Lehrstuhl für Chemie Biogener Rohstoffe; Technische Universität München; Straubing; Germany
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Jia K, Zhang Y, Li Y. Identification and characterization of two functionally unknown genes involved in butanol tolerance of Clostridium acetobutylicum. PLoS One 2012; 7:e38815. [PMID: 22768047 PMCID: PMC3387226 DOI: 10.1371/journal.pone.0038815] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2012] [Accepted: 05/11/2012] [Indexed: 01/07/2023] Open
Abstract
Solvents toxicity is a major limiting factor hampering the cost-effective biotechnological production of chemicals. In Clostridium acetobutylicum, a functionally unknown protein (encoded by SMB_G1518) with a hypothetical alcohol interacting domain was identified. Disruption of SMB_G1518 and/or its downstream gene SMB_G1519 resulted in increased butanol tolerance, while overexpression of SMB_G1518-1519 decreased butanol tolerance. In addition, SMB_G1518-1519 also influences the production of pyruvate:ferredoxin oxidoreductase (PFOR) and flagellar protein hag, the maintenance of cell motility. We conclude that the system of SMB_G1518-1519 protein plays a role in the butanol sensitivity/tolerance phenotype of C. acetobutylicum, and can be considered as potential targets for engineering alcohol tolerance.
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Affiliation(s)
- Kaizhi Jia
- Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Yanping Zhang
- Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Yin Li
- Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- * E-mail:
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Zhang H, Chong H, Ching CB, Song H, Jiang R. Engineering global transcription factor cyclic AMP receptor protein of Escherichia coli for improved 1-butanol tolerance. Appl Microbiol Biotechnol 2012; 94:1107-17. [DOI: 10.1007/s00253-012-4012-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Revised: 03/02/2012] [Accepted: 03/06/2012] [Indexed: 11/28/2022]
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Mao S, Jia K, Zhang Y, Li Y. Use of proteomic tools in microbial engineering for biofuel production. Methods Mol Biol 2012; 834:137-51. [PMID: 22144358 DOI: 10.1007/978-1-61779-483-4_10] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The production of biofuels from renewable sources by microbial engineering has gained increased attention due to energy and environmental concerns. Butanol is one of the important gasoline-substitute fuels and can be produced by native microorganism Clostridium acetobutylicum. To develop a fundamental tool to understand C. acetobutylicum, a high resolution proteome reference map for this species has been established. To better understand the relationship between butanol tolerance and butanol yield, we performed a comparative proteomic analysis between the wild-type strain DSM 1731 and its mutant Rh8 at acidogenic and solventogenic phases, respectively. The 102 differentially expressed proteins that are mainly involved in protein folding, solvent formation, amino acid metabolism, protein synthesis, nucleotide metabolism, transport, and others were detected. Hierarchical clustering analysis revealed that over 70% of the 102 differentially expressed proteins in mutant Rh8 were either upregulated (e.g., chaperones and solvent formation related) or downregulated (e.g., amino acid metabolism and protein synthesis related) in both acidogenic and solventogenic phase, which, respectively, are only upregulated or downregulated in solventogenic phase in the wild-type strain.
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Affiliation(s)
- Shaoming Mao
- Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
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Branched-Chain Higher Alcohols. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2011; 128:101-18. [DOI: 10.1007/10_2011_121] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
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Matsuda F, Furusawa C, Kondo T, Ishii J, Shimizu H, Kondo A. Engineering strategy of yeast metabolism for higher alcohol production. Microb Cell Fact 2011; 10:70. [PMID: 21902829 PMCID: PMC3184262 DOI: 10.1186/1475-2859-10-70] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2011] [Accepted: 09/08/2011] [Indexed: 01/27/2023] Open
Abstract
Background While Saccharomyces cerevisiae is a promising host for cost-effective biorefinary processes due to its tolerance to various stresses during fermentation, the metabolically engineered S. cerevisiae strains exhibited rather limited production of higher alcohols than that of Escherichia coli. Since the structure of the central metabolism of S. cerevisiae is distinct from that of E. coli, there might be a problem in the structure of the central metabolism of S. cerevisiae. In this study, the potential production of higher alcohols by S. cerevisiae is compared to that of E. coli by employing metabolic simulation techniques. Based on the simulation results, novel metabolic engineering strategies for improving higher alcohol production by S. cerevisiae were investigated by in silico modifications of the metabolic models of S. cerevisiae. Results The metabolic simulations confirmed that the high production of butanols and propanols by the metabolically engineered E. coli strains is derived from the flexible behavior of their central metabolism. Reducing this flexibility by gene deletion is an effective strategy to restrict the metabolic states for producing target alcohols. In contrast, the lower yield using S. cerevisiae originates from the structurally limited flexibility of its central metabolism in which gene deletions severely reduced cell growth. Conclusions The metabolic simulation demonstrated that the poor productivity of S. cerevisiae was improved by the introduction of E. coli genes to compensate the structural difference. This suggested that gene supplementation is a promising strategy for the metabolic engineering of S. cerevisiae to produce higher alcohols which should be the next challenge for the synthetic bioengineering of S. cerevisiae for the efficient production of higher alcohols.
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Affiliation(s)
- Fumio Matsuda
- Organization of Advanced Science and Technology, Kobe University, Rokkodaicho, Nada-ku, Kobe, Hyogo, Japan
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From systems biology to biosystems engineering. Biotechnol J 2010. [DOI: 10.1002/biot.201000338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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