title: Enhancement of pyruvate production by osmotic-tolerant mutant of Torulopsis glabrata.
abstract: Pyruvate production by Torulopsis glabrata was used as a model to study the mechanism of product inhibition and the strategy for enhancing pyruvate production. It was found that the concentration of cell growth and pyruvate deceased with the increase of NaCl and sorbitol concentrations. To enhance the osmotic stress resistance of the strain, an NaCl-tolerant mutant RS23 was screened and selected through a pH-controlled continuous culture with 70 g/L NaCl as the selective criterion. Compared with the parent strain, mutant RS23 could grow well on the medium containing 70 g/L NaCl or 0.6 mol/L sorbitol. Pyruvate concentration by the mutant strain RS23 reached 94.3 g/L at 82 h (yield on glucose 0.635 g/g) in a 7-l fermentor with 150 g/L glucose as carbon source. Pyruvate concentration and yield of mutant RS23 were 41.1% and 11.1% higher than those of the parent strain, respectively. The strategy for enhancing pyruvate production by increasing osmotic stress resistance may provide an alternative approach to enhance organic acids production with yeast.
authors.affiliation: The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Southern Yangtze University, Wuxi 214036, China.
authors.forename: Liming
authors.initials: L
authors.lastname: Liu
authors.forename: Qinglong
authors.initials: Q
authors.lastname: Xu
authors.forename: Yin
authors.initials: Y
authors.lastname: Li
authors.forename: Zhongpin
authors.initials: Z
authors.lastname: Shi
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhu
authors.forename: Guocheng
authors.initials: G
authors.lastname: Du
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
mesh_terms: D041221:Candida glabrata / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D005285:Fermentation; D024861:Genetic Enhancement / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D009154:Mutation; D009997:Osmotic Pressure; D019289:Pyruvic Acid / Q000378:metabolism*; D012965:Sodium Chloride / Q000494:pharmacology; D013012:Sorbitol / Q000494:pharmacology
chemical_list: D003470:Culture Media; D012965:Sodium Chloride; D013012:Sorbitol; D019289:Pyruvic Acid