Production and Characterisation of Surfactant Produced by Bacillus subtilis and Its Anti Microbial Study

Abstract

Aim: This study aims to isolate and characterize biosurfactants produced by bacteria, optimization, production conditions, and to evaluate physicochemical and antimicrobial properties for potential industrial and environmental applications. Study Design: A bacterial strain capable of producing biosurfactants was screened and identified. The biosurfactant was extracted, characterized, and tested for emulsification, surface tension reduction, and antimicrobial activity. Place and Duration of Study: The study was conducted at Centre for bioscience and Nanoscience Research, Coimbatore over a period of four months (December 2024 to march 2025). Methodology: Bacterial isolates were screened for biosurfactant production using techniques such as drop collapse assay, haemolytic assay, and emulsification index determination. Biosurfactants were extracted using a solvent extraction method and analyzed using UV-visible spectrophotometry, FTIR and Thin-layer chromatography (TLC). Emulsification activity was tested against hydrocarbons such as crude oil. The antimicrobial potential of the bio surfactant was evaluated against pathogenic bacterial and fungal strains using agar well diffusion method. Results: The bacterial isolate, identified as belonging to the Bacillus genus, produced a biosurfactant with high emulsification activity, particularly against crude oil (E24 index: 100%). TLC analysis suggested a lipopeptide nature, while UV analysis confirmed its presence. The biosurfactant exhibited antibacterial activity against Klebsiella  pneumoniae (15mm inhibition zone), Staphylococcus aureus (16mm), and Proteus mirabilis (17mm). Haemolytic assay indicated potential bio surfactant production, though it was not a definitive test. Conclusion: The study confirms the successful production of a bio surfactant with strong emulsification and antimicrobial properties. These findings highlight its potential applications in bioremediation, enhanced oil recovery, and antimicrobial formulations. Further optimization and purification studies are needed for industrial-scale production.