Heterologous Expression of MTSase and MTHase in Brevibacillus brevis and Its Application

Abstract:

In order to achieve efficient production of the MTSase and MTHase from（< i>Sulfolobus acidocaldarius）ATCC 33909，gene sequence encoding MTSase and MTHase were PCR-amplified using recombined plasmid pET-24a（+）-treY < /i>and pET-24a（+）-treZ which were fused to expressional vector pSVN. The recombined plasmid was transfered into expression host Brevibacillus brevis by electroporation，The enzyme activity of MTSase and MTHase expression in Brevibacillus brevis were 630.0 U/g（wet cell） and 170.0 U/g（wet cell） after cultivated in shake flasks for 48 h. Also presented are the preliminary studies on the reaction conditions of conversion by the enzymes. The optimal conditions for the conversion are as following：the initial pH was 5.5，the reaction temperature was 60 ℃，initial potato starch concentration was 100 g/L，enzymes concentration were MTSase 80 U per gram of substrate、 MTHase 20 U per gram of substrate 、Pullulanase 5 U per gram of substrate and CGTase 15 U per gram of substrate，incubated for 48 h. Under this conditions，the yield of trehalose reached approximately 80.2%.