Isolation and characterization of culturable indigenous endophytic bacteria in the tender coconut

ABSTRACT Tender coconut water is not merely served as a hydrating beverage but is also a good source of nutrients when consumed as a natural liquid refreshment. While providing health benefits, the fruit endosperm was considered sterile for generations. The current study was aimed at studying the presence of endophytic bacteria in tender coconut endosperm and exploring their potential role in the production of metabolites present in Tender coconut water. Endophytic bacteria were isolated from the coconut fruit endosperm – both, from liquid and flesh sources. Morphological and biochemical characterization was carried out for the isolates and were screened for antibacterial activity. Further, the effective isolate was mass multiplied, the metabolites synthesized by the isolate were extracted and the presence of compounds such as stigmasterol, oleic acid, and palmitic acid (2-Phenyl-1,3-Dioxolan-4-yl) methyl ester were identified by Gas chromatography–mass spectrometry analysis and were confirmed with Fourier-transform infrared spectroscopy. Scanning electron microscope images revealed the presence of microbial cells in the endoderm flesh. The isolate VITKUJ4 was identified to be the closest neighbor of Staphylococcus cohnii upon 16S rRNA gene sequencing and phylogenetic analysis. The study indicates the presence of endophytic bacteria in coconut fruit tissue that could be responsible for the beneficial metabolite synthesis. Current study is the first report on isolation and identification of bacteria in coconut fruit endosperm.