THE ACTION OF MICROORGANISMS ON FATS I

Abstract

Conventional Warburg techniques were used to detn. the oxygen consumption of resting cell suspensions in the presence of lipid substrates including natural and pure triglycerides, fatty acid salts and esters. From among 30 cultures capable of showing increased rates of oxygen consumption in the presence of fat, 4 bacterial cultures, Mycobacterium phlei, 2 atypical Pseudomonas fluorescens and a Micrococcus were selected for detailed study. Borate buffer inhibited the oxygen consumption of all cultures whereas increased phosphate buffer concns. produced greater rates of oxygen consumption in the case of 2 cultures. Coconut oil was oxidized at a greater rate than either corn oil or butterfat while 4 pure triglycerides were attacked at varying rates. In the case of the Micrococcus culture, evidence was obtained that oxygen consumption in the presence of fats was due to the utilization of glycerol resulting from the action of lipase. The data indicate that several enzymes are involved in the oxidation of compounds of the saturated fatty acid series by the individual culture, one specific for short chain and one for long chain fatty acids. The pH optima for the oxidation of saturated fatty acid substrates by Mycobacterium phlei were about pH 7.8 for ethyl laurate and pH 5.8 for methyl acetate. With triacetin, the opt. was in the range of pH 7.6 to 7.9. The other cultures showed optima in the range of pH 7.4 to 7.9 with most of the substrates studied. The presence of an enzyme specific for methyl linoleate is suggested by the data obtained on one of the Pseudomonas cultures.