Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10235276 | Process Biochemistry | 2014 | 5 Pages |
Abstract
Bacitracin fermentation by Bacillus licheniformis in this work showed three characteristics: (1) the extracellular propionate, butyrate, acetoin and 2,3-butanediol accumulates under conditions of low dissolved oxygen (zero after 4Â h cultivation), reaching a total content of approximately 11.1Â g/L; (2) cell growth occurs quickly subsequent to cell autolysis and the second growth; and (3) there is a low content of 2,3-butanediol, a reduced product of acetoin catalyzed by acetoin reductase, in the culture process. In this study, addition of MnCl2 (0.3Â mg/L) to the production medium increased the acetoin reductase activity, redirected the NADH oxidation partly from the propionate- and butyrate-production pathways to the 2,3-butanediol synthesis pathway, reduced the intracellular NADH/NAD+ ratio, and facilitated cell growth, ultimately achieving a 11.6% increase in bacitracin production (1076Â U/mL) versus the control. The results provide useful information regarding large-scale bacitracin production by B. licheniformis.
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Authors
Zhi Wang, Yong Wang, Fuli Xie, Shouwen Chen, Junhui Li, Dongsheng Li, Xiong Chen,