Identification and characterization of biosurfactant producing bacteria from Sungai Dungun

Biosurfactants are an amphiphilic compounds synthesized by a variety of bacteria and fungi which as the ability to reduce surface and interface tension. Through their distinctive traits, biosurfactants can be used as substitute for synthetic surfactants in various industries such as food, cosmetics, oil industries, pharmaceutical industries and environmental application. In this study, the objective is to identify and characterize biosurfactant producing bacteria isolated from Sungai Dungun. 3 bacterial isolates were chosen to be characterized in this research which is isolates DSA 4, DSA 7 and DWA 9. The bacterial isolates were grown on Mineral Salt Medium (MSM) that was supplemented with 1% cooking oil. Biosurfactant produced by these bacterial isolates were characterized through emulsification assay, drop collapse assay, oil spreading assay, hydrocarbon degrading capability test and blood haemolysis test. From the results observed, isolate DWA 9 showed the greatest capability in the production of biosurfactant. It showed positive result for drop collapse assay, demonstrated βhemolysis and the widest oil displacement area in oil displacement test and also the highest emulsification activity and hydrocarbon degradation with 34.43 % and 54 % respectively. As for the molecular characterization of the isolates, 16S rDNA gene was successfully isolated from all the isolates. However, after gene sequencing and BLAST analysis, only isolate DSA 7 was able to be identified, which originated from the genus Aeromonas.