Purification and properties of extracellular lipase from Streptomyces rimosus

An extracellular lipase of Streptomyces rimosus R6-554W was isolated from t he culture filtrate by column chromatography using diethylaminoethyl-cellul ose, carboxymethyl-cellulose, hydroxylapatite, Mono S (fast protein liquid chromatography), and Sephadex G-75. It was shown to be a monomeric, basic p rotein (M-r = 27 500, pI = 8.45), active toward triolein and p-nitrophenyl esters, with preference for those with medium size (C-8-C-12) acyl chain le ngth. Interfacial activation was observed with p-nitrophenyl butyrate as su bstrate. The lipase was most active at 50-60 degrees C and in alkaline cond itions around pH 9-10, with p-nitrophenyl palmitate as substrate. It showed high stability at a broad pH range of 4-10 and was fairly thermostable. Di thiothreitol moderately inactivated the enzyme. Phenylmethylsulfonyl fluori de partly inhibited lipase only when added during the hydrolytic reaction. (C) 1999 Elsevier Science Inc. All rights reserved.