Exploration of heterotrophic bacterial diversity in sediments of the mud volcano in the Andaman and Nicobar Islands, India

Abstract

Extreme and specialized environments are home to unique life forms and biological processes. Mud volcanoes represent less explored specialized environments of deeper earth and might harbour unique and useful microbes. With this objective, we studied the aerobic and anaerobic heterotrophic bacteria in mud volcano sediment of Andaman and Nicobar Islands, India by culture method. The bacteria identified in the volcanic sediment belonged to several genera, viz., Bacillus, Brevibacillus, Clostridium, Methylobacterium, Lutibaculum, Pseudomonas, Luteimonas, Halomonas, Acinetobacter, Kocuria, Curtobacterium, and Microbacterium in the phylum Proteobacteria (48.27 % strains), Firmicutes (27.59 %), and Actinobacteria (24.14 %) indicating wide heterotrophic diversity in the subsurface environment. Among the genera, Microbacterium and Acinetobacter were the most dominant, followed by Brevibacillus, Pseudomonas, Clostridium. The identified bacteria are known to harbour unique path ways for synthesis of different enzymes, secondary metabolites, and complex biopolymers, degrade methane and short-chain hydrocarbons, a wide variety of polysaccharides, pollutants including polyethylene, and resistance to heavy metals, heat, and desiccation that enable them to thrive in the subsurface niche and might be potentially useful in the field of agriculture, environment, and industry.