Purification and Characterization of Lipases from Rhizopus chinensis

Abstract:

Two lipase active fractions Lip1 and Lip2 were purified from the cell extract of Rhizopus chinensis CCTCCM201021.Both gave a single band on SDS-PAGE after using ammonium sulfate precipitation、Phenyl-Sepharose FF、DEAE-Sepharose FF and Sephadex G100 gel filtration chromatographies. The molecular masses of two lipases were 59.2kD and 39.4kD respectively. Lip1 and Lip2 showed optimal pH at 8.0 and 8.5 and their optimal temperatures were 40℃ and 35℃ respectively. The substrate specificity of the two lipases was obviously different. Lip1 was more specific to long chain fatty acid of p-nitrophenyl esters while Lip2 had a preference for the hydrolysis of short chain fatty acid of p-nitrophenyl esters. Lip1 had 1,3-position specificity for triacylglycerols hydrolysis while Lip2 had nonspecific position. Both lipases were stimulated by Ca²⁺、Mg²⁺ while SDS had strong inhibition on their activities. Lip1 and Lip2 had good stability in cyclohexane、hexane、heptane and isooctane(30% V/V).