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Bioprocess Biosyst Eng. 2008 Oct;31(6):605-10. doi: 10.1007/s00449-008-0209-5. Epub 2008 Mar 5.

An effective and simplified pH-stat control strategy for the industrial fermentation of vitamin B(12) by Pseudomonas denitrificans.

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State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, People's Republic of China.


In order to improve the productivity of vitamin B(12) by Pseudomonas denitrificans carried out in a 120-m(3) fermenter, the effect of pH on vitamin B(12) biosynthesis was investigated. Results obtained from shake flask experiments showed that the feeding of carbon source (beet molasses or glucose) and methyl-group donor (betaine or choline chloride) significantly influenced the pH and the biosynthesis of vitamin B(12). In contrast to beet molasses or choline chloride, using glucose as a feed medium and betaine as a methyl-group donor, pH could be maintained at a stable range. As a result, higher vitamin B(12) production was achieved. Accordingly, an effective and simplified pH-stat control strategy was established for the fermentation of vitamin B(12) in a 120-m(3) industrial fermenter. When the new pH control strategy was applied, pH was stably kept in the range of 7.15-7.30 during fermentation. Thus, 214.3 microg/mL of vitamin B(12) was achieved.

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