[Combination of growing culture transformation and resting cells transformation of Pseudomonas putida NA-1 for production of 6-hydroxynicotinic acid].

The current technology for microbial hydroxylation of nicotinic acid is a procedure of resting cells transformation. Here it was reported that non-degradation of 6-hydroxynicotinic acid during hydroxylation of nicotinic acid by resting cells was due to existing of nicotinic acid in the transformation mixture, not the death of cells. Therefore it was attempted that the induced cultivation of Pseudomonas putida NA-1 for hydroxylation activity by nicotinic acid was used for accumulation of 6-hydroxynicotinic acid to establish a new technology, a combined technology of growing culture transformation and resting cells transformation. In the combination technology, when 1% of nicotinic acid was kept in cultivation medium by supplement of nicotinic acid at intervals during cultivation of Pseudomonas putida NA-1, the growing culture could consistently hydroxylate nicotinic acid without degradation of its product which was accumulated linearly in the cultivation medium with progress of cultivation; the resting cells obtained from cultivation broth after growing culture transformation still processed a very high hydroxylation activity and could be used to next resting transformation of nicotinic acid. By using of the combined technology, the inducer was saved and the production yield of 6-hydroxynicotinic acid increased above 65%.