Lipases from aspergillus fumigatus; a] productivity and purification under both mesophilic and thermophilic incubatio conditions

Two lipases were produced by Aspergillus fumigatus, a strain isolated from High Dam lake water at Aswan- under both [Lipase "A" at 30 degree cent.] and thermal [Lipase "B" at 45 degree cent. Incubation conditions. Optimal conditions for production were: Tributyrin, 0.2%; incubation period, 5 days; KNO3, 0.2%, phosphate buffer [0.1 M] at pH 6.4. Under these conditions, an obvious shift concerning lipase production towards mesaphily was observed. Coconut oil was the only lipid substance which exerted a clear shift towards thermophily. Results indicated the wide variability that may occur in lipase production by the same fungus in relation to incubation temperatures and thus, a single temperature is insufficient for the determination of lipolysis by different fungi. The two lipases were subjected to a purification procedure which included: dialysis of the cell free extract, ammonium sulphate precipitation and sephadex G 150 column chromatography. The question of whether the two lipases secreted by one fungus at two different temperatures are different kinds of lipases or not will be investigated in the next paper