title: Engineering Saccharomyces cerevisiae for improvement in ethanol tolerance by accumulation of trehalose.
abstract: A genetic recombinant Saccharomyces cerevisiae starter with high ethanol tolerance capacities was constructed. In this study, the gene of trehalose-6-phosphate synthase (encoded by tps1), which catalyzes the first step in trehalose synthesis, was cloned and overexpressed in S. cerevisiae. Moreover, the gene of neutral trehalase (encoded by nth1, trehalose degrading enzyme) was deleted by using a disruption cassette, which contained long flanking homology regions of nth1 gene (the upstream 0.26 kb and downstream 0.4 kb). The engineered strain increased its tolerance against ethanol and glucose stress. The growth of the wild strain was inhibited when the medium contained 6 % or more ethanol, whereas growth of the engineered strain was affected when the medium contained 10 % or more ethanol. There was no significant difference in the ethanol yield between the wild strain and the engineered strain when the fermentation broth contained 10 % glucose (p > 0.05). The engineered strain showed greater ethanol yield than the wild type strain when the medium contained more than 15 % glucose (p < 0.05). Higher intracellular trehalose accumulation by overexpression of tps1 and deletion of nth1 might provide the ability for yeast to protect against environmental stress.
authors.affiliation: a Department of Food and Nutrition , Providence University , Taichung , Republic of China (Taiwan).
authors.forename: Nileema R
authors.initials: NR
authors.lastname: Divate
authors.affiliation: b Department of Cosmetic Science , Providence University , Taichung , Republic of China (Taiwan).
authors.forename: Gen-Hung
authors.initials: GH
authors.lastname: Chen
authors.affiliation: a Department of Food and Nutrition , Providence University , Taichung , Republic of China (Taiwan).
authors.forename: Pei-Ming
authors.initials: PM
authors.lastname: Wang
authors.affiliation: c Department of Animal Science and Biotechnology , Tunghai University , Taichung , Republic of China (Taiwan).
authors.forename: Bor-Rung
authors.initials: BR
authors.lastname: Ou
authors.affiliation: a Department of Food and Nutrition , Providence University , Taichung , Republic of China (Taiwan).
authors.forename: Yun-Chin
authors.initials: YC
authors.lastname: Chung
mesh_terms: D000431:Ethanol / Q000737:chemistry*; D005285:Fermentation; D017353:Gene Deletion; D005818:Genetic Engineering; D005947:Glucose / Q000378:metabolism; D005964:Glucosyltransferases / Q000235:genetics* / Q000378:metabolism; D007218:Industrial Microbiology; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D013312:Stress, Physiological; D014198:Trehalase / Q000235:genetics* / Q000378:metabolism; D014199:Trehalose / Q000378:metabolism*
chemical_list: D029701:Saccharomyces cerevisiae Proteins; D000431:Ethanol; D014199:Trehalose; D005964:Glucosyltransferases; C023180:trehalose-6-phosphate synthase; C000614366:NTH1 protein, S cerevisiae; D014198:Trehalase; D005947:Glucose
keywords: Ethanol tolerance; PCR-based gene disruption; Saccharomyces cerevisiae; Trehalose; neutral trehalase; trehalose-6-phosphate synthase