DELAYED HYDROLYSIS OF BUTTERFAT BY CERTAIN LACTOBACILLI AND MICROCOCCI ISOLATED FROM CHEESE

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Abstract
The lipolytic activities of Lactobacillus and Micrococcus isolates from Cheddar and brick cheese were detd. by measuring the extent of butterfat hydrolysis in a whey-butterfat medium during a 60-day growth and autolysis period at 30[degree]C. Comparisons at 15 and 60 days indicated whether lipolysis occurred during the normal life cycle of the organism or after autolysis. Identities and levels of individual fatty acids liberated were detd. by partition chromatographic methods (B. A. 23: 6230). 12 of 54 Lactobacillus isolates from Cheddar and brick cheese and 4 of ? 8 Micrococcus isolates from raw milk Cheddar cheese were found to possess intracellular lipases (released by autolysis) capable of considerable butterfat hydrolysis (3 to 12.8 millieqs. of total fatty acid liberated per 100 ml. of culture) between pH 5 and pH 6. All 16 active isolates were found to liberate 2 or more of the following fatty acids from butterfat: n-butyric, caproic, caprylic, and capric acids. None of these isolates was found to be lipolytic during its normal life cycle. The 12 Lactobacillus isolates were identified as cultures of L. casei; the 4 Micrococcus isolates were identified as 1 culture of M. conglomeratus, 1 culture of M. freudenreichii, and 2 cultures of M. caseolyticus.
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