Microbial α-amylases:: a biotechnological perspective

Amylases are one of the most important and oldest industrial enzymes. These comprise hydrolases, which hydrolyse starch molecules to fine diverse products as dextrins, and progressively smaller polymers composed of glucose units. Large arrays of amylases are involved in the complete breakdown of starch. However, alpha-amylases which are the most in demand hydrolyse alpha-1,4 glycosidic bond in the interior of the molecule. alpha-Amylase holds the maximum market share of enzyme sales with its major application in the starch industry as well as its well-known usage in bakery. With the advent of new frontiers in biotechnology, the spectrum of alpha-amylase application has also expanded to medicinal and analytical chemistry as well as in automatic dishwashing detergents, textile desizing and the pulp and paper industry. Amylases are of ubiquitous occurrence, produced by plants, animals and microorganisms. However, microbial sources are the most preferred one for large scale production. Today a large number of microbial alpha-amylases are marketed with applications in different industrial sectors. This review focuses on the microbial amylases and their application with a biotechnological perspective. (C) 2003 Elsevier Science Ltd. All rights reserved.