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Yang H, Zong X, Xu Y, Zeng Y, Zhao H. Improvement of Multiple-Stress Tolerance and Ethanol Production in Yeast during Very-High-Gravity Fermentation by Supplementation of Wheat-Gluten Hydrolysates and Their Ultrafiltration Fractions. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:10233-10241. [PMID: 30203970 DOI: 10.1021/acs.jafc.8b04196] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The effects of wheat-gluten hydrolysates (WGH) and their ultrafiltration fractions on multiple-stress tolerance and ethanol production in yeast during very-high-gravity (VHG) fermentation were examined. The results showed that WGH and WHG-ultrafiltration-fraction supplementations could significantly enhance the growth and viability of yeast and further improve the tolerance of yeast to osmotic stress and ethanol stress. The addition of MW < 1 kDa fractions led to 51.08 and 21.70% enhancements in cell-membrane integrity, 30.74 and 10.43% decreases in intracellular ROS accumulation, and 34.18 and 26.16% increases in mitochondrial membrane potential (ΔΨm) in yeast under osmotic stress and ethanol stress, respectively. Moreover, WGH and WHG-ultrafiltration-fraction supplementations also improved the growth and ethanol production of yeast during VHG fermentation, and supplementation with the <1 kDa fraction resulted in a maximum biomass of 16.47 g/L dry cell and an ethanol content of 18.50% (v/v) after VHG fermentation.
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Affiliation(s)
- Huirong Yang
- School of Food Science and Engineering , South China University of Technology , Guangzhou 510640 , PR China
| | - Xuyan Zong
- School of Biotechnology , Sichuan University of Science and Engineering , Zigong 643000 , PR China
| | - Yingchao Xu
- School of Food Science and Engineering , South China University of Technology , Guangzhou 510640 , PR China
| | - Yingjie Zeng
- School of Food Science and Engineering , South China University of Technology , Guangzhou 510640 , PR China
| | - Haifeng Zhao
- School of Food Science and Engineering , South China University of Technology , Guangzhou 510640 , PR China
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Chen X, Song W, Gao C, Qin W, Luo Q, Liu J, Liu L. Fumarate Production by Torulopsis glabrata: Engineering Heterologous Fumarase Expression and Improving Acid Tolerance. PLoS One 2016; 11:e0164141. [PMID: 27711153 PMCID: PMC5053504 DOI: 10.1371/journal.pone.0164141] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 09/20/2016] [Indexed: 01/12/2023] Open
Abstract
Fumarate is a well-known biomass building block compound. However, the poor catalytic efficiency of fumarase is one of the major factors preventing its widespread production. To address this issue, we selected residues 159HPND162 of fumarase from Rhizopus oryzae as targets for site-directed mutagenesis based on molecular docking analysis. Twelve mutants were generated and characterized in detail. Kinetic studies showed that the Km values of the P160A, P160T, P160H, N161E, and D162W mutants were decreased, whereas Km values of H159Y, H159V, H159S, N161R, N161F, D162K, and D162M mutants were increased. In addition, all mutants displayed decreased catalytic efficiency except for the P160A mutant, whose kcat/Km was increased by 33.2%. Moreover, by overexpressing the P160A mutant, the engineered strain T.G-PMS-P160A was able to produce 5.2 g/L fumarate. To further enhance fumarate production, the acid tolerance of T.G-PMS-P160A was improved by deleting ade12, a component of the purine nucleotide cycle, and the resulting strain T.G(△ade12)-PMS-P160A produced 9.2 g/L fumarate. The strategy generated in this study opens up new avenues for pathway optimization and efficient production of natural products.
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Affiliation(s)
- Xiulai Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China
- Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi, China
| | - Wei Song
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China
- Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi, China
| | - Cong Gao
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China
- Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi, China
| | - Wen Qin
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China
- Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi, China
| | - Qiuling Luo
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China
- Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi, China
| | - Jia Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China
- Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi, China
| | - Liming Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China
- Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi, China
- * E-mail:
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Li S, Liu L, Chen J. Mitochondrial fusion and fission are involved in stress tolerance of Candida glabrata. BIORESOUR BIOPROCESS 2015. [DOI: 10.1186/s40643-015-0041-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Abstract
Background
Recently, cell tolerance toward environmental stresses has become the major problem in the development of industrial microbial fermentation. Acetoin is an important chemical that can be synthesized by microbes. Its toxicity was investigated using Candida glabrata as the model in this study.
Results
A series of physiological and biochemical experiments demonstrated that the organic solvent acetoin can inhibit cell growth by increasing intracellular reactive oxygen species (ROS) production and inducing damage to mitochondria and cell apoptosis. Integrating RT-PCR experiments, the genes fzo1 and dnm1 were overexpressed to regulate the balance between mitochondrial fusion and fission. Enhancement of mitochondrial fusion was shown to significantly increase cell tolerance toward acetoin stress by inhibiting ROS production and increasing the intracellular adenosine triphosphate (ATP) supply, which was also demonstrated by the addition of citrate.
Conclusions
Regulating mitochondrial fusion-fission may be an alternative strategy for rationally improving the growth performance of eukaryotes under high environmental stress conditions, and also expands our knowledge of the mechanisms of cell tolerance through the processes of energy-related metabolic pathways.
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