Purification and characterization of lipases from Aspergillus repens and Eurotium herbariorum NU-2 used in "Katsuobushi" molding

Lipases (triacylglycerol acylhydrolase, EC 3.1.1.3) were purified from Aspe rgillus repens and Eurotium herbariorum NU-2 strain by using a DEAE-Sephade x A-50 column and preparative electrophoresis. The purified enzymes from A. repens and NU-2 had molecular weights estimated by SDS-PAGE to be 38,000 a nd 65,000, respectively. Lipase from A. repens had a pH optimum of 5.3 and a temperature optimum of 27 degrees C, while for the NU-2 strain correspond ing values were pH 5.2 and 37 degrees C. The specific activity of NU-2 was about twice that of A. repens. Substrate specificity toward olive oil or tr iolein and positional specificity for hydrolyzing the 1 (3)-position ester bonds of triacylglycerol are discussed for both enzymes.