title: Enhanced conversion of soluble starch to trehalose by a mutant of Saccharomycopsis fibuligera sdu.
abstract: In our previous studies, it was found that Saccharomycopsis fibuligera sdu cells could accumulate 18.0% (gg(-1)) trehalose from soluble starch in SSY medium. However, the yeast strain contained high activities of acid and neutral trehalases, which were reported to mobilize trehalose accumulated by the cells during fermentation. In order to enhance the yield of trehalose, it is necessary to remove the trehalase activities from the cells. By mutagenesis of ethylmethanesulfonate, one mutant that assimilated trehalose very slowly, but grew on other carbon sources as fast as its parent strain, was isolated. In Biostat B2 2-1 fermentation, trehalose accumulation of the mutant was much higher than that of the wild type when grown in YPS medium containing starch. The activities of acid and neutral trehalases of this mutant were much lower than those of the wild type, respectively. We think the reduction of acid and neutral trehalase activities is considered to be responsible for the increased yield of trehalose accumulated by the mutant.
authors.affiliation: The State Key Laboratory of Microbial Technology, Shandong University, Jinan, Shandong 250100, China. zhenming@sdu.edu.cn
authors.forename: Zhenming
authors.initials: Z
authors.lastname: Chi
authors.forename: Juan
authors.initials: J
authors.lastname: Liu
authors.forename: Jianrong
authors.initials: J
authors.lastname: Ji
authors.forename: Zhaolei
authors.initials: Z
authors.lastname: Meng
mesh_terms: D019149:Bioreactors; D005020:Ethyl Methanesulfonate / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D024861:Genetic Enhancement / Q000379:methods*; D016297:Mutagenesis, Site-Directed; D012442:Saccharomycopsis / Q000187:drug effects / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D013045:Species Specificity; D013213:Starch / Q000378:metabolism*; D014198:Trehalase / Q000235:genetics / Q000378:metabolism; D014199:Trehalose / Q000096:biosynthesis*
chemical_list: D013213:Starch; D005020:Ethyl Methanesulfonate; D014199:Trehalose; D014198:Trehalase