Microbial hydration of<i>Cis</i>‐9‐alkenoic acids

Abstract

Abstract The activity of a cis ‐9‐fatty acid hydratase produced by a Pseudomonas sp. (NRRL B‐3266) isolated from soil was compared with that of another isolate previously reported (NRRL B‐2994). The presence of appropriate fatty acids for at least 4 hr during aerobic growth in yeast extract medium increased subsequent enzyme activity. Such cells anaerobically hydrated several cis ‐9‐alkenoic acids to 10‐hydroxy fatty acids and aerobically formed 10‐keto acids, which were partially degraded to shorter chain keto acids. Melting point, gas chromatography, infrared, mass spectrometry and optical rotatory dispersion data are given. Six fatty acids having cis ‐9‐unsaturation produced hydrated products, but several enoic acids having trans ‐9‐unsaturation or double bonds in other than the 9 position were inactive as substrates. The (−)‐10‐hydroxypalmitic acid produced from palmitoleic acid is considered to have the D configuration. Yields of 71% crude crystalline product from 15 g of oleic acid and 53% from 11 g of palmitoleic acid were obtained in 5‐liter anaerobic fermentations with NRRL B‐3266. Methyl esters, triolein and oleyl alcohol were not hydrated.