A novel high maltose-forming α-amylase from Rhizomucor miehei and its application in the food industry.
A novel α-amylase gene (RmAmyA) from Rhizomucor miehei was cloned and expressed in Pichia pastoris. RmAmyA showed 70% amino acid identity with the α-amylase from Rhizomucor pusillus. A high α-amylase activity of 29,794.2 U/mL was found through high cell density fermentation. The molecular mass of RmAmyA was determined to be 49.9 kDa via SDS-PAGE. RmAmyA was optimally active at 75 °C and pH 6.0, and it did not require Ca2+ to improve its activity. It exhibited broad substrate specificity towards amylose, amylopectin, soluble starch, pullulan, and cyclodextrins. High level of maltose (54%, w/w) was produced after liquefied starch was hydrolysed with RmAmyA for 16 h. Moreover, the addition of RmAmyA into Chinese steamed bread resulted in 7.7% increment in the specific volume, and 17.2% and 11.5% reduction in the chewiness and hardness, respectively. These results indicate that RmAmyA might be a potential candidate for applications in the food industry.
['Wang|Yu-Chuan|YC|', 'Hu|Hui-Fang|HF|', 'Ma|Jun-Wen|JW|', 'Yan|Qiao-Juan|QJ|', 'Liu|Hai-Jie|HJ|', 'Jiang|Zheng-Qiang|ZQ|']
D001939:Bread D019649:Food Industry D006863:Hydrogen-Ion Concentration D006868:Hydrolysis D008320:Maltose D010843:Pichia D020103:Rhizomucor D013213:Starch D013379:Substrate Specificity D013696:Temperature D000516:alpha-Amylases
α-Amylases Rhizomucor miehei Pichia pastoris Maltose Chinese steamed bread High-cell density fermentation