Diversity in the cultural characteristics of rhizobacteria from coastal sand dune plants and bioprospecting them for the production of extracellular enzymes

Microorganisms have become increasingly important as producer of industrial enzymes and antibiotics. Due to their diversity in their biochemcial properties and growth characteristics, they are much suitable for environmental applications and genetic manipulations. Hence, attempts are being made to isolate and characterize bacteria from less explored ecosystems so as to have diverse cultural and biochemical characteristics. Coastal sand dunes are one such relatively unexplored marine ecosystem. The plants surviving in these harsh environmental systems may harbor diverse and new beneficial bacteria in their rhizosphere. Hence, in the present study, a total of 40 different bacteria were isolated from seven different rhizosphere samples of coastal sand dune plants along the East Coast of Tamil Nadu, in Bay of Bengal India. Among the samples maximum numbers of bacterial colonies were observed in the rhizosphere of Spinifex sp. that were collected from Kanathur, Chennai. The bacterial colonies were found to be in various shapes such as rhizoidal, irregular, and circular. Some colonies were found be mucoidal in nature. The results for the biochemical characterization showed that all the bacteria were rod shaped and most of them were gram positive. Out of 40, 35 strains produced catalase and 17 produced oxidase positive results. Majority of them were actively motile bacteria. A total of 13 strains were found to be fluorescent pseudomonads as they exhibited fluorescence in King’s B Medium. The screening for their useful bioactivities showed that the bacterial strains were efficient for producing different enzymes such as the tannase, lipase, amylase and protease which can be used for industrial applications. Hence, the study is significant in finding morphologically, culturally and biochemically diverse rhizobacteria capable of producing industrially important enzymes from a less explored marine ecosystem.