Isolation and characterization of novel secondary metabolites producing actinobacterium from Sundarbans mangroves using integrative approaches

Asha, Kannan (2020) Isolation and characterization of novel secondary metabolites producing actinobacterium from Sundarbans mangroves using integrative approaches. PhD thesis, Indian Institute of Science Education and Research Kolkata.

Text (PhD thesis of Kannan Asha (15RS025)) 15RS025.pdf - Submitted Version Restricted to Repository staff only Download (8MB)

Abstract

The present thesis explores the molecular diversity of sediment Actinobacteria from Sundarbans mangrove ecosystem, along with the isolation, characterization and activity assessment of a novel secondary metabolites producing actinobacterium Myceligenerans indicum sp. nov. This thesis investigates the following key questions: 1) How widespread are Actinobacteria in the intertidal sediments of Sundarbans? 2) How does the secondary metabolite producing actinobacterial diversity in Sundarbans sediments differ from other intertidal and mangrove sediments globally? 3) Can a novel actinobacterium have the ability to produce novel secondary metabolites? 4) Can novel actinobacterial secondary metabolites exhibit unique mechanisms linked to antimicrobial activity? To answer these questions, four objectives were formed. The findings in this thesis revealed the presence of Phylum Actinobacteria as a major player in secondary metabolites producing bacterial communities in Sundarbans sediments by clone library approaches. Comparison of global biogeographic patterns provided indications of the presence of undiscovered, unique secondary metabolites producing actinobacterial communities in Sundarbans sediments. Additionally, a novel actinobacterium, Myceligenerans indicum sp. nov. was identified and characterized using polyphasic approaches. Crude and semi-purified extracts of Myceligenerans indicum sp. nov. were further investigated using spectroscopic approaches and bioactivity was determined by antibacterial assays. Semi pur ified extracts indicated the possible presence of a ring structure, as well as functional groups such as azo (-N=N-), nitroso (-N=O) and carbonyl (-C=O) groups. Consequently, further characterizations and activity assessments of these extracts are warranted.

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