| abstract |
A microbial process for the preparation of a compound of formula (I) from a compound of formula (II) wherein R is an alkali metal or ammonium ion by submerged strain cultivation capable of 6beta-hydroxylated compound of formula (II) by aerobic fermentation and separation and purifying the product of formula (I) formed during the biological conversion. Said fermentation comprises the steps of culturing a strain of Micromonospora which is capable of 6-beta-hydroxylation of a compound of formula (II) - wherein R is as defined - at 25 to 32 ° C on a nutrient medium containing usable sources of carbon, nitrogen and mineral salt; which is to be transformed into a developed culture, subsequently hydroxylating the substrate until the biological conversion is complete, then separating the compound of formula (I) from the culture medium and, if necessary, purifying it. |