title: Steroid conversions by Flavobacterium dehydrogenans in two-liquid-phase systems.
abstract: The production of 4-androstene-3, 17-dione by Flavobacterium dehydrogenans from androstenolone-acetate in octane/culture (v/v = 1:1) two-liquid phase systems was compared with the conversion rate in a Tween-containing medium commonly used in industry, and in a culture where no organic solvent or detergent was added. Variation of the cell density of the cultures at the moment of steroid, Tween, and/or organic solvent addition showed that the highest conversion rate in the three systems was reached with cells which were in the late exponential growth stage. The rate of 4-androstene-3, 17-dione production at the optimal cell density in the two-liquid-phase system and Tween medium were ca. 6 and 1(1/2) times as high, respectively, as in the aqueous medium without addition. The beneficial effect of octane on the rate of steroid conversion during growth could be explained by viability changes as measured by a new method to determine viability. Furthermore, our results show that a very high degree of conversion can be reached in the two-liquid-phase system [more than 98% (w/w)] which cannot be obtained in an aqueous medium. An easy way to recover the product in high purity is proposed.
authors.affiliation: Department of Biochemistry, Agricultural University, De Dreijen 11, 6703 BC Wageningen, The Netherlands.
authors.forename: S
authors.initials: S
authors.lastname: Boeren
authors.forename: C
authors.initials: C
authors.lastname: Laane