Expression and functional analysis of a hyperglycosylated glucoamylase in a parental host, Aspergillus awamori var. kawachi

Abstract

A modified glucoamylase gene (glaA) with an extra Thr- and Ser-rich Gp- I domain (T. Semimaru, M. Goto, K. Furukawa, and S. Hayashida, Appl. Environ. Microbiol, 61:2885-2890. 1995) was introduced into a mutant parental host, Aspergillus awamori var. kawachi, in which the original glaA gene had been completely deleted and replaced with the hygromycin phosphotransferase gene. The modified glaA was successfully expressed and secreted. The modified glucoamylase possessed higher digestibility of raw corn starch and higher stabilities in response to heat and extreme pH.