Production of testosterone from cholesterol using a single-step microbial transformation of Mycobacterium sp

A novel single-step microbial transformation process for the production of testosterone (TS) from cholesterol by Mycobacterium sp was investigated. It was found that the supply of reducing power, NADH, from the metabolism of glucose was necessary for the reduction of androst-4-en-3,17-dione (AD) to TS. The cultivation time for the maximum accumulation of TS and the residual glucose increased in parallel with the amount of glucose supplemented in fermentation cultures. After the glucose in the fermentation culture was completely consumed, most of the TS was oxidized to AD. Adding a larger amount of glucose could prevent oxidation of TS to AD. Under optimal fermentation conditions, the maximum molar conversion rate of TS from cholesterol was 51% in a 5-L surface-aerated fermentor after 120 h cultivation.