Bioprospecting for moderately halophilic eubacteria for potential biotechnological applications from Sambhar Lake, Rajasthan, India

Abstract

Sambhar Lake an athalassohaline habitat located at 27°58′N 75°55′E, Rajasthan, India is a major source of salt production in the country. From surface lake water, soil, and shore sediments, fifty-nine moderate halophiles were isolated which were subsequently grouped according to shape, colony characteristics, and staining into twenty-two isolates. Fourier transform infrared spectroscopy profiling identified these isolates as eubacterial with characteristic C=O stretching of ester functional groups. Observations further indicated similarity within some Halomonas isolates indicating potential phylogenetic lineages. The FASTA sequences obtained after sequencing with universal bacterial primers were processed for phylogenetic analysis. Predominantly Gram-positive genera like Alkalibacillus, Amphibacillus, Marinococcus, Piscibacillus, Planococcus, Salinicoccus, Staphylococcus and Virgibacillus with only two Gram-negative strains of Halomonas were identified. The genus Amphibacillus was recognized for the first time in the study of Sambhar Lake. Despite being moderately halophilic, several isolates exhibited high salt tolerance with growth in 25% salt. All isolates were mesophilic with growth observed between 18-42℃ which matches the temperature profile of the region. Analysis of hydrolytic potential identified eighteen isolates as protease producers, thirteen as lipase producers, and ten as cellulase-producing strains. Further evaluation showed the dominance of C10:0, C12:0, C13:0, C14:0, C15:0, C16:0, C17:0, C18:0, C18:1 FAMEs, among which the presence of C16:0 and C18:1 fatty acid indicated probable antimicrobial potentials of these strains.