Bioconversion of 3beta-acetoxypregna-5,16-diene-20-one to androsta-1,4-diene-3,17-dione by mixed bacterial culture

摘要

Aims: To isolate a bacterium capable of degrading 3beta-acetoxypregna-5,16-diene-20-one (16-DPA) to androsta-l,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-l and C-2 positions and (iii) cleavage of C-l7 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.