Cold-active Microbial Enzymes

Absolutely the largest proportion of the Earth’s biosphere is consisting of microorganisms that thrive in cold environments and known as psychrophiles/psychrotrophs. Their ability to survive in the cold environments is based on the capacity to synthesize coldadapted enzymes, such as amylases, proteases, lipases, pectinases, cellulases etc., along with other specific characteristics. Enzymes are essential constituents of all forms of life on the Earth, including prokaryotes, fungi, plants and animals. Commercial applications of microbial enzyme are attractive due to the relative ease of largescale production as compared to enzymes from plants and animals. At present, only ~2% of the microorganisms on the Earth have been commercially exploited and amongst these there are only a few examples of psychrophiles and psychrotrophs [1]. Around 85% of the Earth is occupied by cold ecosystems including the ocean depths, polar and alpine regions. Out of which ~70% is covered by oceans that have a constant temperature of 4-5 °C, irrespective of the latitude. Microbes growing at low temperature regions are important for their metabolic contribution in the ecosphere as well as for their enzymes with potential industrial applications [2]. During the past decade it has been recognized that cold-adapted microorganisms provide a wide biotechnological potential over the use of organisms and their enzymes which operate at higher temperatures [3,4]. Cold-adapted microorganisms are potential source of cold-active enzymes which had high catalytic efficiency with low and moderate temperatures at which homologous mesophilic enzymes are not active, and are thermolabile [5]. The potentials of cold-active enzymes along with their producing organisms have been reviewed time to time [3,4,6]. Cold-active enzymes confer low activation energies and high activities at low temperature which are favorable properties for the production of relatively insubstantial compounds. The application of cold-active enzymes enables lowering of temperature without loss of efficiency, which results in saving of energy consumption and have great potential for various biotechnological processes [7]. The low temperature stability of cold-active enzymes 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 chemistry, as well as their widespread biotechnological and industrial applications such as food processing, additive in detergents and food industries, wastewater treatment, biopulping, environmental bioremediation in cold climates, biotransformation and molecular biology applications.