Extracellular enzymes of cold-adapted bacteria from Arctic sea ice, Canada Basin

A total of 338 aerobic heterotrophic bacterial strains were isolated from Arctic sea ice, Canada Basin (77A degrees 30'N-80A degrees 12'N). The capability of the isolates to produce protease, lipase, amylase, chitinase, beta-galactosidase, cellulase and/or agarase was investigated. Isolates that were able to degrade tributyrin, skim milk, starch, lactose and chitin accounted for 71.6, 65.7, 38.5, 31.6 and 16.9% of sea ice strains, respectively. Lipase producers and/or protease producers were phylogenetically widespread among the isolated strains. Starch and/or lactose hydrolytic strains were mainly distributed among Colwellia, Marinomonas, Pseudoalteromonas, Pseudomonas and Shewanella isolates. Pseudoalteromonas tetraodonis, Pseudoalteromonas elyakovii, Bacillus firmus and Janibacter melonis isolates all have the ability to degrade chitin. Only some strains belonging to Pseudoalteromonas genus scored positive for agarase (6) and cellulose (9). The temperature dependences for lipase activities were determined for five psychrophilic and six psychrotolerant bacteria. At low temperatures, the psychrophilic bacterial lipase activity was not significantly higher than psychrotolerant bacterial lipase, though all lipases showed remarkably high activity with 10-36% residual activity at 0A degrees C.