Steroid transformation by mutants of Mycobacterium sp. with altered response to antibiotics

Mycobacterium sp. NRRLB3683 which is capable to convert β-sitosterol to 1,4-androstadiene-3, 17-dione (ADD) was treated with methyl methane sulfonate and two strains with altered sensitivity to various antibiotics were obtained. One of the strain was steroid 1(2)-dehydrogenase negative and the other positive. Efficiency of utilization of sterols followed the order β-sitosterol > cholesterol > soluble cholesterol. The steroid 1(2)-dehydrogenase negative strain was capable of producing 17KS (AD) from β-sitosterol and converting AD to testosterone and ADD to AD suggesting the negative role of 1(2)-dehydrogenase in sterol side chain cleavage and decrease in hydrogenase activity by mutation. But this enzyme can perform the reverse reaction under aerobic condition.