Abstract:

Sea ice covering Arctic sea provides a unique habitat with lower temperature and higher salinity, containing a complex microbial community. Numerous sea ice bacteria could produce extracellular enzymes, and the property of enzymes hydrolyzing proteins or lipids was much higher than that hydrolyzing polysaccharids. Temperature and salinity were two leading environment factors directly affecting the survival and activity of sea ice bacteria. This paper showed, with a high growth temperature limit at 35 °C , 76% of sea ice bacteria producing protease was cold adapted. However, 98% of those proteases had an optimum temperature higher than 35°C , and 62% of them even higher than 45 °C . Nearly all sea ice bacteria producing protease were halophilous or salt adapted.