The Biohydrogenation of Linoleic Acid by Rumen Micro-organisms

Abstract

The ability of the micro-organisms present in the rumen to hydrogenate C18-unsaturated fatty acids is now well documented and has been the subject of several recent reviews1, 2, 3). Furthermore, it has been shown by WARD et al.4) that an important intermediate in the hydrogenation of C18-unsaturated fatty acids in the rumen is C18:1 trans-11 isomer. This isomer is characteristically found in the tissues of ruminant animals2). In particular, it has been shown that, when dairy cows are given a diet containing a high proportion of C18-unsaturated fatty acids which are readily accessible to the rumen micro-organisms, the concentration of this trans-11 monoene undergoes a significant increase in both the tissues5, 6) and milk fat7, 8, 9).In the present investigation, a study has been made of the effects of different concentrations of substrate on the biohydrogenation of linoleic acid by rumen micro-organisms in vitro, and analyses have been made of the isomers produced as intermediates in the biohydrogenation process.