Corticosteroids microbiological 1,2-dehydrogenation

In a process for 1,2-dehydrogenation of corticosteroids with Arthrobacter or Corynebacterium species involving enzyme-induction subsequent to cultivation but prior to dehydrogenation, the induction of the steroid 1,2-dehydrogenase is begun by addition of 0.02-0.2 mg/ml of a steroid of the androstane or pregnane series only after the growth of the bacteria in the stationary phase of the culture, an amount of a C- and /or N-source such as to give a 0.01-0.1% concentration being simultaneously added to the culture so as to give rise to a secondary growth. A 1,2-satd. corticosteroid is added to the resulting highly active culture (which can be diluted before the addition), the dehydrogenation and the isolation of the product being effected in a conventional manner. The new method of induction gives very high enzyme levels, and the dehydrogenation proceeds extremely rapidly and is unaccompanied by steroid degradation or reduction.