Effect of Phosphate Ion and Ammonia-Nitrogen on Colistin Production by Bacillus polymyxa : Studies on Colistin Fermentation (II)

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Factors affecting colistin production by bacillus polymyxa var. KY-7584 were investigated using Morido's fermentation medium (Medium M). The more suitable combination of two kinds of inorganic salts in the medium remarkably affected colistin production, and the initial pH before inoculation was also an important factor for the better production of colistin. Further studies with the modified Morido's medium showed that the correlative factors of inorganic salts were the phosphate ion (PO_4^<3->) and ammonia-nitrogen (NH_4-N). The optimum PO_4^<3-> concentration for colistin production was below 0.01%. The optimum NH_4-H concentration for colistin production was 0.17% at the PO_4^<3-> level that did not inhibit colistin production. B. polymyxa var. KY-7584 showed maximum accumulation of colistin (40,100u/ml) when the PO_4^<3-> and NH_4-N concentrations were both limited at initial pH 7.2. The maximum production was three times more than that in Medium M. Under these conditions the maximum cell concentration showed an increment of about 50% compared with that in Medium M. This study also revealed the correlation between PO_4^<3-> and NH_4-N concentrations in colistin production.
公益社団法人日本生物工学会の論文
1983-08-25