Lipolytic activity of various microorganisms isolated from cottonseed.

Deteriorated cottonseeds containing large amounts of free fatty acids in the oil were reported in a previous work (Mayne, 1956) to contain or to carry on their surfaces large numbers of lipolytic microorganisms. It was noted also that certain kinds of lipolytic organisms were found in the samples of deteriorated seed (rarely on the samples of prime seed), while other lipolytic types were found in both kinds of seed. In an effort to find any differences in the activity of these types, a program involving quantitative measurements of lipolysis was carried out on cultures of 42 bacterial and 43 mold isolates from cottonseed. Two types of quantitative measurements of lipolysis have been reported in the literature: One involves the use of enzyme preparations (Ramakrishnan and Banerjee, 1952; Fodor and Chari, 1949; Fiore and Nord, 1949), and the other depends on measurements of the total titratable acidity developing in a culture of the microorganisms (Mukherjee, 1951; Goldman and Rayman, 1952). The latter workers developed a method for making a stable emulsion of minute oil globules of uniform size. This technique was an important contribution since the ease of lipolysis is influenced by the availabilitv (surface area) of the fat. It was thought that a more exact knowledge of fat decomposition would be gained by measuring only the acidity in the extracted fat, as distinguished from total titratable acidity, developing in a culture of the microorganisms in question. Such a test was developed for this study to reveal any differences among the various species of microorganisms in their use of fat and in the acidity of the fat extractable from the cultures. These differences might explain then the occurrence of some types of lipolytic organisms in seed with little free fatty acid.