GROWTH AND CHOLESTEROL OXIDATION BY MYCOBACTERIUM SPECIES IN TWEEN 80MEDIUM

Mycobacterium strain DP was isolated from marine coastal sediment and tested for its ability to oxidize cholesterol in Tween 80-cholesterol (2.59 mM) medium. Strain DP degraded cholesterol to 4-cholesten-3-one (cholestenone), 4-androsten-3,17-dione (AD), 1,4-androstadien-3,17-dio ne (ADD), testosterone, and 1-dehydrotestosterone (DHT). Cholesterol d isappeared in about 4 days. Cholestenone, AD, testosterone, and DHT ac cumulations were transient with peak concentrations of 300, 600, 30 to 40, and 21 muM. ADD production peaked after 6 days with a concentrati on of 1,100 muM. Peak ADD concentrations and production rates compared well with those reported for strain NRRL B3683 on cyclodextrin medium . Tween 80 medium was superior to finely dispersed cholesterol particl es for both strains. In comparison, NRRL B3683 (patented for its abili ty to accumulate AD and ADD) on Tween 80 medium transiently accumulate d more AD (approximately 1,000 muM) than did strain DP, but ADD accumu lations (200 muM) were significantly lower than those for strain DP. S train DP could be adapted to grow on ADD, which was initially inhibito ry at 3.25 mM. ADD-adapted strain DP cultures produced approximately f our times as much DHT from ADD than unadapted cultures did from choles terol, showing that additional manipulation might enhance testosterone production. We believe that ADD toxicity might account for the low AD D accumulations by NRRL B3683 in Tween 80 medium.