Preliminary Characterization of the Lipase of Mycotorula lipolytica

Abstract

Lipase activity was detd. by adding 1 ml. of culture or cell-free filtrate to 50 ml. of an emulsion of 5% butterfat in 0.25% agar (containing 1:1500 formaldehyde) and incubating at 37 C for 48 hrs., shaking twice daily. To a 10 g. portion of incubated emulsion was added 25 ml. of neutral 95% ethyl alcohol and 25 ml. diethyl ether and the mixture titrated with N/20 KOH in methyl alcohol to phenolphthalein end-point. The lipase of M. lipolytica hydrolyzed butterfat within range of pH 4 to 8, pH 6.2-6.5 being optimum. The lipase was active at temp. from 10 to 52 C; temps. of 37 C and above inactivated the enzyme, the reaction being more rapid at the higher temps. studied. When cell-free enzyme prepns. were stored for 3 mos. in closed containers, they lost about 1/8 of their original activity at 5 C and 1/3-1/2 at 25 C. Concentrating of the enzyme by lyophilizing, frothing, or salting-out procedures was achieved with varying success, but high losses were encountered by all 3 methods.