A novel maltooligosaccharide-forming amylase from Bacillus stearothermophilus

Publication date: Available online 20 May 2019Source: Food BioscienceAuthor(s): Yinglan Wang, Sihui Pan, Zihang Jiang, Siyu Liu, Yan Feng, Zhengbiao Gu, Caiming Li, Zhaofeng LiAbstractA novel maltooligosaccharide-forming amylase (MFAse) from Bacillus stearothermophilus (Bst-MFAse) was heterologously expressed in B. subtilis and purified by hydrophobic and ion-exchange chromatographies. Bst-MFAse, an approximately 58 kDa monomer, could effectively hydrolyze linear α-glucan with DP > 6 and slightly hydrolyze maltohexaose. In addition, Bst-MFAse was proved to majorly produce maltopentaose and maltohexaose from starch and categorized as a maltopentaose-forming amylase. The action pattern was analyzed using amylopectin and amylose as substrate, showing that Bst-MFAse could rapidly reduce iodine blue value. Thus, Bst-MFAse was categorized as both a maltopentaose-forming amylase and an endo-amylase. During the initial period (2 h) of amylolysis, Bst-MFAse mainly cleaved amylopectin (18.7%) than amylose (14.0%). However, the final conversion rate (24 h) of amylose (68.8%) was slightly higher than that of amylopectin (64.8%). Bst-MFAse may have great potential applications in industry due to its highly specific activity, unique substrate specificity, and end-type product pattern.

Source: Food Bioscience - May 21, 2019 Category: Food Science Source Type: research