Abstract: Special challenges for microorganisms in cold ecosystems include reduced enzymatic reaction rates, limited bioavailability of nutrients, and frequent extremes in pH and salinity. To thrive successfully in low temperature environments, psychrophiles have evolved a complex range of structural and functional adaptations. Psychrophiles produce cold-active enzymes, which can be up to ten times more active at low and moderate temperatures compared with their mesophilic homologues. The enzymes of polar microorganisms are shaped by their adaptations to the permanently low temperatures. In addition, strongly differing environments, such as permafrost, glaciers and sea ice, have contributed to additional functional diversity. Microorganisms that thrive in the polar zones are a vast reservoir of cold-adapted enzymes. These enzymes could be beneficial in many industrial applications. Research using polar microorganisms to find new bioproducts has been mainly focused on enzymes that can be used in a range of industrial processes. The biotechnological value of cold-adapted enzymes stems from their high turnover (kcat) at low to moderate temperatures and their high thermolability at elevated temperatures. In recent years, a large number of new polar microbial enzymes have been continuously discovered, indicating that polar microbes have become an important source of novel enzymes. This review describes the research progress of new microbial enzymes over the past five years, and focuses on the discovery of important industrial enzymes, such as protease, lipase/esterase and carbohydrate-degrading enzymes, with good commercial prospects.

Key words: polar microorganism, exploitation of enzyme resource, protease, lipase, esterase, carbohydrate-degrading enzymes