Inactivation and Augmentation of the Primary 3-Ketosteroid-Δ1-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.