An overview of cold-active microbial A-amylase: Adaptation strategies and biotechnological potentials

Absolutely the largest proportion of the Earth's biosphere is comprised of organisms that thrive in cold environments are known as psychrophiles and psychrotrophs. Their ability to proliferate in the cold is predicated on a capacity to synthesize cold-adapted enzymes like amylases, proteases, lipases, pectinases, cellulases, etc. that could be used in low-energy processes. Amylases have most widely been reported to occur in microorganisms, although they are also found in plants and animals. Cold-active α-amylases confer low activation energies and high activities at low temperature which are favorable properties for the production of relatively insubstantial compounds. In addition, these enzymes have an advantage under extreme low temperature conditions due to their inherent greater membrane fluidity, production of cold-acclimation proteins and the mechanism of freeze tolerance. The low temperature stability of cold-active amylases has been regarded as the most important characteristics for use in the industry because of considerable progress towards energy savings but unfortunately these enzymes have largely been overlooked. Now this situation is changing which recently fascinated the scientific community to focus in many fields, such as clinical, medicinal and analytical chemistries, as well as their widespread biotechnological applications such as food processing, additive in detergents, waste-water treatment, biopulping, environmental bioremediation in cold climates and molecular biology applications. This review addresses the present status of knowledge on the source, structure, production and molecular characteristics of cold-active α-amylases and their biotechnological applications. © 2011 Asian Network for Scientific Information.