Samples analysing hydrolytic enzymatic activity of deep sea bacteria. © Padmanabhan, V. P. et al
Researchers on a maiden exploration of bacterial diversity in the deep sea sediments of the Bay of Bengal say it's a hot spot for microbes-derived natural products waiting to be tapped1.
The Bay of Bengal is the largest bay in the world with a bottom rich in sediments from rivers of the Indian subcontinent, including from the Himalayan range. The bay's deep sea ecosystem had remained unexplored from the point of microbial diversity and bio-prospecting. Researchers from Anna University and the National Institute of Ocean Technology, both in Chennai, sampled sediments from three different places in the bay — from a depth of 1850 metres off Barren Island of the Andaman Sea, and 2000 m and 1400 m off Chennai and Cudallore.
The samples collected by India's research vessel Sagar Manjusha were subjected to phylogenetic analysis to find genetic connections and relationships between species. They identified abundant high gram-positive bacteria in all deep sea sediments and some unusual bacterial species such as Firmicutes, Proteobacteria, and Actinobacteria.
"This is the first report on the isolation of Brucella, Fictibacillus, Mesorhizobium and Cobetia species from deep sea sediments," they say in the paper.
Almost 91% of the isolates produced at least one of the extracellular hydrolytic enzymes, such as caesinase, alpha-amylase, urease, gelatinase, lipase and deoxyribonuclease. Streptomyces was the only genus which showed antibacterial activity.
The researchers say this wide distribution of extracellular hydrolases in deep sea bacteria shows that they are metabolically diverse and could play an important role in biogeochemical cycles. The deep-sea hydrolases and the antibacterial compounds from Streptomyces species can be further characterized for the discovery of industrially important novel catalysts and bioactive molecules, respectively, the researchers say.
References
1. Padmanaban, V. P. et.al. Phylogenetic identification and metabolic potential of bacteria isolated from deep sea sediments of Bay of Bengal and Andaman Sea. Ind. J. Exp. Biol. 57 (2019) Article
