Enzymatic conversion of phyto:sterol(s) to androstane steroid(s) - in presence of bi:carbonate source to increase yield

摘要

Prodn. of androstane steroids (I) from phytosterols (II) having branched chains at C-24 is effected by selective cleavage of the 17-side chains of (II) by exposing them to enzymes produced by a microorganism of the genus NFcardia, Mycobacterium, Arthrobacter or Corynebacterium in the presence of a one-carbon-unit cpd. (III) which can be converted to bicarbonate ion or CO2 by the microorganism. Prefd. (II) are sitosterol and campesterol. Prefd. microorganisms are Mycobacterium spp. NRRL B-2805, B-3683 and B-15051. The process is pref. effected by culturing the microorganism in an aq. nutrient medium contg. (II) and (III) under submerged aerobic conditions, pref. at 10-37 deg.C for 0.5-12 dyas. The concn. of (III) is pref. sufficient to give a bicarbonate ion concn. of 25-200 mM. (III) may be e.g. NaHCO3, NH4HCO3, CaCO3, CO2 or H2CO3. (I) are useful as intermediates for steroid hormone synthesis. Addn. of (III) increases the yield of (I).