Conversion of Natural Substances by Microbial Enzymes

Microbiological transformations of lipids: acyl-specific hydrolysis of lard by yeasts

The fatty acid and positional specificities of Saccharomyces cerevisiae (UI-SACCH) and Schizosaccharomyces octosporus (NRRL Y-854) in the hydrolysis of lard were studied by using gas-liquid chromatography. Synthetic triglycerides were used to determine the positional specificities of the lipases of both organisms. Palmitic acid is specifically cleaved from all three triglyceride ester positions by S. cerevisiae, while S. octosporus was able to cleave stearic acid at either position 1 or position 3 of the glycerol moiety. Preparative scale fermentation with 200 g of lard per liter yielded 48.4 g of palmitic acid per liter with S. cerevisiae and 42 g of stearic acid per liter with S. octosporus. The free fatty acids produced by microbial transformation of lard were characterized spectrally (1H and C nuclear magnetic resonance and mass spectrometry) and chromatographically (thin-layer and gas chromatographies).

Synthesis of glycols by microbial transformation of some monocyclic terpenes

The transformation of three monocyclic terpenes by three soil microorganisms have been studied. The organisms were isolated on, and grew rapidly in, mineral salts medium containing the appropriate terpene substrates as sole carbon sources. These organisms belong to the class Fungi Imperfecti, and two of them have been tentatively identified as Cladosporium species. A Cladosporium species designated T(1) was isolated from terpene-soaked soil, using 1-menthene as the sole source of carbon. The major catabolic product isolated from the growth medium of this organism was found to be a cyclic 1,2-diol identified as trans-p-methane-1,2-diol. A similar but biochemically distinct Cladosporium sp. designated T(7) was isolated on D-limonene. After growth, the medium of this organism contained 1.5 g/liter of the analogous product, trans-limonene-1,2-diol. Minor quantities of the corresponding cis-1,2-diol were also isolated. The third organism, designated as laboratory culture T(8), was isolated on 3-menthene and yielded a diol identified as trans-p-menthane-3,4-diol. From these results it is concluded that the formation of diols is a common intermediate in the fungal metabolism of monocyclic terpenes.

Steroids and steroidases. II. A general gas-liquid chromatographic assay for steroidases and its application to the C-1,2-dehydrogenase of Bacillus sphaericus

A gas–liquid chromatographic method was developed which is suitable for the preliminary assay of steroidases contained in wholly unrefined preparations. Its scope was illustrated by application to the Δ1-dehydrogenase of Bacillus sphaericus. Progesterone induction of B. sphaericus resulted in a sixfold increase in Δ1-dehydrogenase activity, and the enzyme was found to be stable indefinitely when the B. sphaericus preparations were stored as acetone powders at −20°. The pH dependence of the enzyme showed a maximum at 7.5. The optimum concentration of the electron acceptor used, menadione, was also determined.