화학공학소재연구정보센터
Applied Microbiology and Biotechnology, Vol.98, No.3, 1291-1299, 2014
Biotechnological transformation of hydrocortisone to 16 alpha-hydroxy hydrocortisone by Streptomyces roseochromogenes
Streptomyces roseochromogenes is able to hydroxylate steroid compounds in different positions of their cycloalkane rings thanks to a cytochrome P-450 multi-enzyme complex. In this paper, the hydroxylation of the hydrocortisone in the 16 alpha position, performed by bacterial whole cells, was investigated in both shake flask and fermentation conditions; the best settings for both cellular growth and transformation reaction were studied by investigating the optimal medium composition, the kinetic of conversion, the most suitable substrate concentration and the preferred addition timing. Using newly formulated malt extract- and yeast extract-based media, a 16 alpha-hydrohydrocortisone concentration of 0.2 +/- 0.01 g L-1 was reached in shake flasks. Batch experiments in a 2-L fermentor established the reproducibility and robustness of the biotransformation, while a pulsed batch fermentation strategy allowed the production to increase up to 0.508 +/- 0.01 g L-1. By-product formation was investigated, and two new derivates of the hydrocortisone obtained during the bacterial transformation reaction and unknown so far, a C-20 hydroxy derivate and a C-21 N-acetamide one, were determined by NMR analyses.