Cloning and Expression of MTSase and MTHase from Sulfolobus solfataricus in E.coli / 微生物学通报

ABSTRACT

The genes of maltooligosyl trehalose synthase (MTSase) and maltooligosyl trehalose tetrahydrolase(MTHase) from Sulfolobus solfataricus ATCC 35092 were amplified using PCR. The expression plasmids, pTrc99a-MTSase and pTrc99a-MTHase, were constructed by inserting these two DNA fragments into E. coli expression vector pTrc99a. The specific activity of MTSase and MTHase in E. coli BL21(DE3) at optimal fermentation conditions reached 31.3U/g (wet cell) and 403U/g (wet cell), respectively. The biotransformation of partially hydrolyzed starch to trehalose catalyzed by MTSase and MTHase was carried out at 75℃ and pH 5.0. The highest yield of trehalose (ca. 53.6%) was gained when the original starch concentration was 15%(w/v) and the DE value was 10.