High Expression of mdlA Gene in Pichia pastoris and Study of Properties of the Recombinant Lipase

The mono-and diacylglycerol lipase(MDGL)-encoding gene(mdlA) was inserted into methanol-inducible expression vector pPIC9K.The linearized recombinant plasmid was uransformed into chromosome of Pichia pastoris GS115 strain by electroporation.Some high-copy transformants(His~(+)Mut~(+)) were picked up by G-418 and conformed by PCR.SDS-PAGE analysis indicated efficient expression of recombinant MDGL.Some enzymatic properties of the recombinant MDGL were also determined.The activity of the recombinant MDGL was up to 325U/mL under the optimal conditions and no activity was detected towards olive oil.The amount of fatty acid produced by the catalysis of recombinant MDGL and triacylglycerol lipase had a increase of 93.5% over triacylglycerol lipase lonely.