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Enhancement of pyruvate production by osmotic‐tolerant mutant of Torulopsis glabrata
Author(s) -
Liu Liming,
Xu Qinglong,
Li Yin,
Shi Zhongpin,
Zhu Yang,
Du Guocheng,
Chen Jian
Publication year - 2007
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.21290
Subject(s) - sorbitol , fermentation , mutant , strain (injury) , osmotic shock , biochemistry , osmotic concentration , yield (engineering) , chemistry , sodium pyruvate , food science , yeast , biology , materials science , anatomy , metallurgy , gene
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. Biotechnol. Bioeng. 2007;97: 825–832. © 2006 Wiley Periodicals, Inc.