No abstract

No abstract

No abstract

The spirosolane side chain of solasodine has been cleaved by cholesterol preinduced Mycobacterium sp. NRRL B‐3805 to yield 1‐androstene‐3,17‐dione (AD), a key intermediate for the synthesis of androgenic drugs. Conversion up to 34% has been recorded in shake flask culture after 192 h incubation period using dimethyl‐formamide as carrier for solasodine addition.

Bioconversion of 16-dehydropregnenolone acetate (16-DPA) to androsta-1,4-diene-3,17-dione (ADD), an intermediate for the production of female sex hormones, by mixed culture of Pseudomonas diminuta MTCC 3361 and Comamonas acidovorans MTCC 3362 is reported. Various physicochemical parameters for the bioconversion of 16-DPA to ADD have been optimized in shake flask cultures. Nutrient broth inoculated with actively growing co-culture proved ideal for bacterial growth and bioconversion. A temperature range of 35-40 degrees C was most suitable; higher or lower temperatures adversely affected the bioconversion. Dimethylformamide below 2% concentration was the most suitable carrier solvent. Maximum conversion was recorded at 0.5 mg mL(-1) 16-DPA. A pH of 5.0 yielded a peak conversion of 62 mol % in 120 h incubation period. Addition of 9alpha-hydroxylase inhibitors failed to prevent further breakdown of ADD to nonsteroidal products. 16-DPA conversion in a 5 L fermenter followed a similar trend.

Aims: To isolate a bacterium capable of degrading 3b-acetoxypregna-5,16-diene-20-one (16-DPA) to androsta-1,4-diene-3,17-dione (ADD) and to decipher the biodegradation pathway. Methods and Results: Isolation on mineral salt agar containing 16-DPA as sole carbon source yielded two bacteria identified as Pseudomonas diminuta and Comamonas acidovorons. These bacteria failed to degrade 16-DPA individually in pure cultures but converted 16-DPA to ADD in a mixed culture. The intermediates accumulated during the bioconversion were identified as pregna-4,16-diene-3,20-dione and pregna-1,4,16-triene-3,20-dione. Conclusions: The degradation pattern of 16-DPA by mixed bacterial culture revealed the reaction sequence as (i) cleavage of C-3 acetyl function, (ii) dehydrogenation at C-1 and C-2 positions and (iii) cleavage of C-17 side-chain. Significance and Impact of the Study: The present work opens a new approach towards the production of a female sex hormone precursor and elucidates the biodegradation pathway of 16-DPA by mixed bacterial culture.

No abstract

No abstract