Inactivation and augmentation of the primary 3-ketosteroid-{delta}1- dehydrogenase in Mycobacterium neoaurum NwIB-01: biotransformation of soybean phytosterols to 4-androstene- 3,17-dione or 1,4-androstadiene-3,17-dione.

3-Ketosteroid-Delta(1)-dehydrogenase, KsdD(M), was identified by targeted gene disruption and augmentation from Mycobacterium neoaurum NwIB-01, a newly isolated strain. The difficulty of separating 4-androstene-3,17-dione (AD) from 1,4-androstadiene-3,17-dione (ADD) is a key bottleneck to the microbial transformation of phytosterols in industry. This problem was tackled via genetic manipulation of the KsdD-encoding gene. Mutants in which KsdD(M) was inactivated or augmented proved to be good AD(D)-producing strains.