Purification and characterization of extracellular lipase from Acinetobacter radioresistens CMC-2

A novel lipase with the favorable alkaline and thermostable characteristics was produced from Acinetobacter radioresistens CMC-2. The crude lipase with 49.5% of total activity was recovered after centrifugation, ultrafiltration and lyophilization. The crude preparation was further purified to a homogeneous state by column chromatography on phenyl sepharose and ultrafiltration, giving 26.6% of total activity recovery. The molecular weight and isoelectric point of the lipase determined by SDS-PAGE and IEF were 38 kDa and 4.5, respectively. The lipase could be classified as a 1,3-positional specific enzyme and possessed the (R)-stereoselectivity in the hydrolysis of racemic suprofen trifluoroethyl ester in isooctane. Moreover, effects of pH, temperature, metal ions, surfactants and organic solvents on the enzyme activity and stability were reported.