A mutant, TS-N-121 was obtained by mutation and plate screening from a parent strain Mycobacterium fortuitum MF2 , which could transform sterol into androstanedione as the main product.

从雄的转化产生菌偶分枝杆菌MF2出,经紫外诱变结合平板筛选,获得要转化生产睾的突变TS-N-121。