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Enhanced production of d ‐lactic acid by S porolactobacillus sp. Y 2–8 mutant generated by atmospheric and room temperature plasma
Author(s) -
Sun Jiaduo,
Wang Yan,
Wu Bin,
Bai Zhongzhong,
He Bingfang
Publication year - 2014
Publication title -
biotechnology and applied biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.468
H-Index - 70
eISSN - 1470-8744
pISSN - 0885-4513
DOI - 10.1002/bab.1267
Subject(s) - lactic acid , fermentation , chemistry , biochemistry , food science , pyruvic acid , biology , bacteria , genetics
To improve the production of d ‐lactic acid, atmospheric and room temperature plasma ( ARTP ) was used to generate mutations in S porolactobacillus sp. Y 2–8. An efficient mutant YBS 1–5 was rapidly isolated by implanting ARTP twice with a 100 W radio‐frequency power input, 10 standard liters per minute of the helium flow, and a 2 mm treatment distance. Significant improvement of d ‐lactic acid productivity (1.39 g L −1 H −1 ) by YBS 1–5 was achieved, and it was 41.84% higher than the productivity (0.98 g L −1 H −1 ) of Y 2–8. Moreover, the dry cell weight of YBS 1–5 was 16.7% higher than that of Y 2–8. Metabolic activities of concerned substrates related with key enzymes of d ‐lactic acid fermentation were analyzed by Biolog approach. Results showed that the activities of the key enzymes glucokinase and d ‐lactate dehydrogenase in mutant YBS 1–5 were increased by approximately 45% and 66%, respectively, in comparison with those of the strain Y 2–8. Fed‐batch fermentation further improved the productivity; 127 g L −1 d ‐lactic acid in 74 H by YBS 1–5 with higher productivity (1.72 g L −1 H −1 ) was achieved. The subculture experiments indicated that YBS 1–5 was genetically stable after eight generations.