Thermostable α-amylase producing maltohexaose from a new isolated Bacillus sp. US100: study of activity and molecular cloning of the corresponding gene

摘要

A Bacillus sp. US100 strain was isolated from Tunisian hot spring soil. This strain secretes a thermoactive amylase having an optimal temperature of 82°C and a remarkable thermostability with a half time of 40 min at 110°C in the presence of 20% (w/v) of substrate. The main end products of its action on starch are maltohexaose and maltopentaose which is the smallest substrate hydrolyzed by this enzyme. The molecular cloning, in E. coli, of a 3-kb DNA fragment encoding for this activity is also reported.