Abstract:A cDNA gene(AusfaeA),which encodes a feruloyl esterase(FAE) A from Aspergillus usamii E001(abbreviated to AusFaeA),was amplified by RT-PCR.The expressing plasmid pPIC9K-AusfaeA was constructed and linearized with SacⅠ,followed by transforming it into Pichia pastoris GS115 by eletroporation.The recombinant P.pastoris GS115/AusfaeA was screened by G418 and then was induced with methanol to express reAusFaeA.The purified reAusFaeA showed one single band on SDS-PAGE with an apparent molecular weight of 36.0 kDa.The feruloyl esterase activity of the reAusFaeA against methyl ferulate(MFA) reached 29.4 U/mg determined by HPLC.Its optimal temperature and pH were 45 ℃ and 5.0,respectively.It was stable at a temperature of 45 ℃ or below,and at a pH range of 4.0 ~6.0.Its enzymatic acvitity was not signficantly affected by an array of tested metal ions.This indicated that the AusfaeA was successfully expressed in P.pastoris and the excellent properties of the reAusFaeA make it a potential candidate for applications in industrial processes.
