Diversity of complex polysaccharide degrading bacteria from the sediments of interlinked high Arctic fjords, Svalbard

Abstract

Polysaccharides comprise a major component of marine organic matter and are mostly produced by phytoplankton through primary production. The present study reports the polysaccharide degrading ability of cold-adapted heterotrophs from interlinked high Arctic fjords in the Svalbard archipelago. One hundred and ninety-five polysaccharide degrading bacteria isolated from inner and outer fjord sediments, 148 bacterial isolates showed complex polysaccharide degrading enzyme activity. Pectinase was the most predominant polysaccharide-degrading enzyme, followed by agarase, alginate lyase, chitinase, and laminarinase. Xylanase and carboxy methyl cellulase were showed in a relatively lesser activity. Heterotrophic bacterial isolates from the inner and outer shelf regions showed variation in their complex polysaccharide utilization ability. In Kongsfjorden, pectinase producing bacteria were more prevalent in the outer fjord, while chitinase producing bacteria dominated the inner fjord. In Krossfjorden, chitinase producing bacteria were frequently encountered in the outer fjord, whereas pectinase, laminarinase, and alginate lyase producing bacteria dominated the inner fjord. The results of the study indicated that a significant difference in polysaccharide-degrading bacterial phylotypes between the inner and outer fjords (p<0.05). Major polysaccharide-degrading bacteria belonged to phylum Proteobacteria, followed by Firmicutes, Actinobacteria, and Bacteroidetes. The dominant polysaccharide-degrading genera are Marinobacter, Bacillus, Salinibacterium, Alcaligenes, and Planococcus. The findings reveal the availability of a wide range of polysaccharide substrates in fjord sediments and the significant functional role of the heterotrophic bacterial community in the remineralization process of fjord environments.