Abstract: Biosurfactants are amphiphilic mixes created by microorganisms as optional metabolite. The unique properties of biosurfactants make them possible to replace or to be added to synthetic surfactants which are mainly used in food, cosmetics, petroleum refining and pharmaceutical industries and in environmental applications. In this study 25 hydrocarbon-degrading bacteria were screened for biosurfactant production. All of the bacterial isolates were grown in Mineral Salt Medium (MSM) with addition of 1% (v/v) vegetable oil as carbon source. The presence of biosurfactant was determined by the blood hemolysis, drop collapse tests, emulsification assay, Emulsification index (E24), foaming activity, lipase activity, haemolytic assay, oil spreading and tilted glass slide. Microplate analysis and surface tension measurement. Only 1 isolate, Achromobacter xylosoxidans GSMSR13B was found to be positive for all the qualitative and qualitative tests and reducing the surface tension of the medium to 47.8 dynes/cm with emulsification index of 28.7 %. This isolate produced biosurfactant optimally at pH 8.0 and incubation temperature of 37°C. Furthermore, Achromobacter xylosoxidans GSMSR13B when grown in MSM with addition of 1% (v/v) glycerol and 1.5 g/L NH4NO3 C/N ratio 16:1 produced biosurfactant with percentage of surface tension reduction at 56% or 28.6 dynes/cm with %EI24 of 36%. This percentage of surface tension reduction represents an increasing reduction in surface tension of medium by 33% over the value before optimization. This study showed that Achromobacter xylosoxidans GSMSR13B has the ability to biodegrade hydrocarbon and concurrently produce bio surfactant.
Golamari Siva Reddy, Botlagunta Mahendran and Ronda Srinivasa Reddy, 2018. Screening and Optimization of Achromobacter xylosoxidans GSMSR13B Producing Bacteria. Journal of Food Technology, 16: 14-22.