Screening, Isolation And Molecular Identification Of Biosurfactant Producing Bacteria From Rhizosphere Soil Samples

Abstract

Biosurfactants (BS) are a class of secondary metabolite that has surface active properties and are produced by large number of microorganisms. The current study is aimed at isolation and screening of BS producing bacteria from different rhizosphere samples, characterize them and study for BS production in different media. Using the enrichment culture method, 80 morphologically different bacterial isolates were isolated from various rhizosphere samples. Twenty isolates were chosen and further screened for BS activity [penetration assay, microplate assay, oil-displacement method, emulsification assay (EA) and emulsification index (EI%)]. Among the twenty isolates tested, Bacillus sp. RMS25 demonstrated good EI percent and EA, as well as high BS production. The bacterial isolate RMS25 has shown high BS production, yielding 562 mg L-1. The isolate RMS25 was identified as Bacillus vallismortis using biochemical techniques and the 16S rRNA gene sequence. Molecular identification of the isolate RMS25 was performed by16S rRNA sequencing, and the sequences were analysed using NCBI BLAST. The BLAST findings for isolate RMS25 revealed a 99 percent match with the Bacillus vallismortis database sequence. The sequences were submitted to GenBank and assigned the accession number MW468676.