Comparison of extracellular Escherichia coli AppA phytases expressed in Streptomyces Lividans and Pichia Pastoris

摘要

A phytase gene (appA) from Escherichia coli was cloned into Streptomyces lividans and expresse as an extraced-lular protein which was then compared with the same enzyme expressed in pichia pastoris The phytase expressed in S.lividans was not glycosylated and had a molecular mass of 45kDa Compared with teh glycosylated phytase expressed in P.Pastoris thsi non-glycosylated phytase was 25-50% less active (p < 0.05) at pH 2 TO 3.5 or at 45 and 55 deg C but 50% more active (p <0.05) at 75 deg C The themo-tolerance of the non-glycosylated phytase was 26 and 48% higher (p <0.05) than that of the glycosylated phytase at 45 and 55 deg C but was 80 and 94