Bioconversion of soysterols to androstenedione by Mycobacterium fortuitum subsp. fortuitum NCIM 5239, a mutant derived from total sterol degrader strain

BACKGROUND: The bioconversion of soysterols to androstenedione (AD) by microbial cleavage of C‐17 side chain is of practical interest since AD serves as the starting compound for the production of the majority of pharmaceutically active steroids. A total soysterols degrader strain was subjected to combined mitomycin C and UV treatments and a mutant designated Mycobacterium fortuitum subsp. fortuitum NCIM 5239 was isolated that accumulated AD as major bioconversion product. RESULTS: The maximum bioconversion of soysterols to AD (71.3 mol %) was obtained at 30 °C, pH 5, 15% inoculum grown for 48 h, glycerol (12.68 g L^?1) and urea (1.06 g L^?1) as carbon and nitrogen sources, respectively, at C:N ratio of 10, the use of 10% polypropylene glycol‐400 (PPG‐400) as soysterols carrier solvent and 3 mg mL^?1 concentration of soysterols after 240 h incubation period in shake flask culture. In a laboratory scale fermentor, a maximum of 64.8 mol % bioconversion of soysterols to AD was recorded after 99 h. CONCLUSION: The mutant Mycobacterium fortuitum subsp. fortuitum NCIM 5239 possesses high potential for industrial production of AD from soysterols. Copyright © 2010 Society of Chemical Industry