Functional expression of keratinase (kerA)gene from bacillus licheniformis in pichia pastors

摘要

A 1.2kb DNA fragment coding for the pro-peptide and mature keratinase from Bacillus licheniformic PWD-1 (kerA) was cloned into vectors pPICZ#alpha#A and pGAPZ#alpha#A for extracellular expression in the methylotrophic yeast,Pichia pastoris.Recombinant Keratinase was secreted by the pPICZ#alpha#A-kerA transformants 24h after methanol induction of shake-flask cultures,and reached a finaly yield of 124mg l~(-1)(285U ml~(-1))144h after the induction.The recombinant keratinase was glycosylated (approx 38kDa),and was optimal between pH 8.5-9.5 and between 55degC-60degC using azokeratin as substrate.The enzyme degraded bovine serum albumin,cellagen,and soy protein concentrate.In conclusion.P.pastoris can be used as an efficient host to express keratinase for untritional and environmental applications.