Induction and repression of steroid hydroxylases and dehydrogenases in mixed culture fermentations.
نویسندگان
چکیده
Some factors affecting induction and repression of steroid-transforming enzymes were studied in single and mixed cultures of Arthrobacter simplex, Nocardia restrictus and Streptomyces roseochromogenes. In single or mixed cultures induction and repression of I -dehydrogenase, I 6a-hydroxylase, and 20-ketoreductase were found to be dependent on the type of steroid substrate and the composition of the medium. In mixed cultures patterns of growth as well as enzyme induction and repression were altered by culture interaction. An observation having practical significance was that I 6ahydroxylation and r-dehydrogenation of ga-fluorohydrocortisone to triamcinolone could be done, in a single fermentation operation, by a mixed culture of A. simplex and S. roseochromogenes. The practicality of this transformation derives from the fact that 20-ketoreductase, an enzyme responsible for the production of undesirable by-products in cultures of A. simplex, was completely repressed in the mixed culture system. Although growth of A. simplex was suppressed by metabolites of S. roseochromogenes, conversion of steroids with this mixed culture was reproducible and controllable within a wide range of ratios of organisms in the starting mixtures.
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عنوان ژورنال:
- Journal of general microbiology
دوره 55 1 شماره
صفحات -
تاریخ انتشار 1969