Diversity of culturable psychrotrophic bacteria from arctic soil samples

Abstract

The study of psychrotrophic microorganisms has gained interests in recent times because cold region serves as sources of unique microorganisms for biotechnological applications. The present study was aimed at investigating the diversity of culturable psychrotrophic bacteria associated with four frozen arctic soil samples collected from different points in Svalbard Hornsund. A total of 40 psychrophilic and psychrotolerant bacteria were isolated under aerobic conditions at 20°C. The mean viable bacterial count ranged from 1.2 x 104 to 5.4 x 105 cfu/mL. The isolates were analysed on the basis of morphological, physiological and molecular characteristics. The results of Gram stain reactions showed that Gram negative bacteria (n = 24) were predominant in the samples. Based on the 16S rRNA gene sequence analysis, the isolates (n = 40) could be categorised into five genera, comprising of Pseudomonas as the most abundant followed by Arthrobacter, Bacillus, Flavobacterium, Sphingomonas belonging four phyla (Proteobacteria, Actinobacteria, Firmicutes and Flavobacteria) and one unclassified Bacterium.