Bacterial diversity and bioprospecting for cold-active enzymes from culturable bacteria associated with sediment from a melt water stream of Midtre Lo_v^·enbreen glacier, an Arctic glacier

Abstract

Culturable bacterial diversity of Midtre Loenbreen glacier, an Arctic glacier, was studied using 12 sediment samples collected from different points, along a transect, from the snout of Midtre Lo_v^·enbreen glacier up to the convergence point of the melt water stream with the sea. Bacterial abundance appeared to be closer to the convergence point of the glacial melt water stream with the sea than at the snout of the glacier. A total of 117 bacterial strains were isolated from the sediment samples. Based on 16S rRNA gene sequence analyses, the isolates (n = 117) could be categorised in to 32 groups, with each group representing a different taxa belonging to 4 phyla (Actinobacteria, Bacilli, Flavobacteria and Proteobacteria). Representatives of the 32 groups varied in their growth temperature range (4-37 °C), in their tolerance to NaCl (0.1-1 M NaCl) and in the growth pH range (2-13). Only 14 of 32 representative strains exhibited amylase, lipase and (or) protease activity and only one isolate (AsdM4-6) showed all three enzyme activities at 5 and 20 °C respectively. More than half of the isolates were pigmented. Fatty acid profile studies indicated that short-chain fatty acids, unsaturated fatty acids, branched fatty acids, cyclic and cis fatty acids are predominant in the psychrophilic bacteria.