Lipolytic Activity of Microorganisms at Low and Intermediate Temperatures. III. Activity of Microbial Lipases at Temperatures Below 0°C

Abstract

SUMMARY The lipolytic activity at ‐7, ‐18, and ‐29°C of strains of Pseudomonas fragi, Staphylococcus aureus, Geotrichum candidum, Candida lipolytica, Penicillium roqueforti , and an unidentified Penicillium sp. in emulsions of corn oil, coconut oil, and lard was determined. The action was measured by titratable acidity and by quantitative determination of the fatty acids by chromatography. The lipases from these microorganisms showed considerable activity within 2‐4 days at ‐7°C and within a week at ‐18°C. Activity at ‐29°C was evident within 3 weeks by some of the cultures, particularly on corn oil. The rate of lipolysis in frozen substrates was directly related to their degree of unsaturation. However, there also were differences among genera. The lipase of G. candidum had considerably more specificity for oleic and linoleic acids than any of the others. P. fragi and C. lipolytica were least able to attack the β‐esterified palmitic acid of lard. The ability of S. aureus to attack this position readily at 35° C was nullified by lowering the temperature to –18° C. A similar effect was observed on the mold lipase.