An overview on microbial α-amylase and recent biotechnological developments

The α-amylase is one of the most promising commercial enzymes that has tremendous applications in various industries. Microbial α-amylase share almost 25-30% in enzymes market due to its catalytic function in several industries, including sugar, detergent, paper, textile, pharmaceutical industries, etc. The α-amylase hydrolyze glycosidic linkages of structural components of starch result in maltose, glucose, and high fructose syrups. Starch, the second most abundant organic substance on the Earth, is a readily available, low-cost renewable substrate mainly in biorefinery and food industries. Amylases are ubiquitous in nature due to its involvement in carbohydrate metabolism. The α-amylases of microbial origin have technical advantage as compared to animal and plant origin. Considering physicochemical properties, bacterial α-amylases are most diverse. However, for industrial purpose, these properties of the biocatalyst, either individually or in a combination, are required to modify through genetic and protein engineering according to the targeted process. The review presents an overview on the current findings of microbial sourced α-amylases, commercial applications, market trends on relevant industries and achieved improvements in thermostability, catalytic function, pH tolerance, Substrate and product specificities through recombinant DNA technology and protein engineering.