Hydrogenation of C18 unsaturated fatty acids by pure cultures of a rumen micrococcus

Approximately 70% of the fatty acids present in plant lipids are unsaturated; the major component is cis-9,cis-12,cis-15-octadecatrienoic acid (Garton 1963). After ingestion by ruminants, these acids are readily hydrogenated by microorganisms in the rumen to form a complex mixture of positional and geometrical C18 isomers (Shorland et al. 1957; Ward, Scott, and Dawson 1964; Wilde and Dawson 1966; Kemp and Dawson 1968).