Purification and characterization of a lipase from Neurospora sp. TT‐241

An extracellular lipase, which is produced by the Neurospora sp. TT‐241 strain, grown on wheat bran at 30°C for 4 d, was purified 370‐fold with an overall yield of 16%. The molecular weight was determined to be 55 kDa by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis. The optimal pH at 30°C and optimal temperature at pH 6.5 were 7 and 45°C, respectively. The lipase was stable in the pH range of 5 to 8, and it was temperature‐sensitive. It was active on a wide range of natural substrates of either vegetable or animal origins and toward p ‐nitrophenyl esters, greatly favoring those containing C 4 acyl groups. It cleaved all of the ester bonds of triolein; however, the 1‐ or 3‐ester bond was the preferred target. A complete inhibition by diisopropyl fluorophosphate suggested the presence of a serine residue at the active site. Partial inhibition was shown by either Hg 2+ or chloramine T. Enzyme activity persisted in nonionic surfactants, a water‐miscible solvent (dimethylsulfoxide), and a water‐immiscible solvent (hexane).