Microbial Diversity of the Sundarbans, the World’s Largest Tidal Mangrove Forest, and Its Bioprospects

Abstract

Sundarbans, the world’s largest tidal mangrove forest, lies in the delta of the Ganges, Brahmaputra, and Meghna rivers. The ecosystem is dynamic and the biodiversity is enormously rich. The debris and the waste materials generated by local industry as well as domestic sources flowing through the rivers accumulate in this deltaic region. This detritus-based hugely productive ecosystem supplies large amounts of organic substances to the resident organisms and builds up a productive ecosystem. Mangroves are one of the striking sources of microbial diversity. Microbes have been explored as a potential source of bioactive compounds for novel pharmaceutical applications. Till date, very little work has been carried out on the microbial diversity of the Sundarbans. Few attempts have been made to explore the culturable and un-culturable microorganisms of this ecosystem. Till date, two novel species, Streptomyces sundarbansensis sp. nov. and Streptomyces euryhalinus sp. nov., have been reported from this region. Several other actinomycetes were also isolated and a few bioactive compounds have been purified. Moreover, industrially important enzymes such as protease, esterase, and ribonucleases have been purified and characterized from bacteria isolated from the Sundarbans. Many halophilic cyanobacterial strains have been isolated; among them, Oxynema aestuarii sp. nov. was reported as a new cyanobacterial species. Further, the diversity of un-culturable bacteria and archaea of the Sundarbans have been explored by applying the metagenomic approach, and the sequence data have been analyzed using bioinformatics tools. Several studies have documented Proteobacteria as the dominant phylum, while Firmicutes, Chloroflexi, Planctomycetes, and Actinobacteria were found seasonally at different locations of the mangrove forest. Looking into the dynamic microbial community composition, the Sundarbans ecosystem has a great potential for the discovery of novel microbial species and deliver bioactive compounds for industrial, medical, and environmental applications.