Screening and Characterization of Biosurfactant Producing Bacteria from Soil Samples in Ogun-State, Nigeria

Abstract

Aims: Biosurfactants are surface active compound that are synthesized by microbes like bacteria, fungi and yeast. Biosurfactant have different applications in the industries. Biosurfactant can be used as emulsifiers, as well as demulsifiers, wetting agents, foaming agents, spreading agents, food ingredients and detergents etc. Ability of the microorganisms to produce biosurfactant was carried out using different screening techniques in a stepwise process. Study Design: Soil samples were randomly collected from 8 different automobile shops in Ogun State, Nigeria. Place and Duration of Study: Soil samples were collected from eight different automobile shops located at Oru-Ijebu, Ago-iwoye, Abeokuta and Ijebu-ode in Ogun state, Nigeria during the rainy season in the month of July, 2015. Methodology: Biosurfactant-producing bacterial isolates were isolated and screened for biosurfactant production using haemolytic, oil spreading, drop collapse, bacteria adhesion to hydrocarbon and emulsification index tests (E. I). Bacteria were identified using biochemical tests and best biosurfactant producer bacteria was identified by molecular techniques. Bacteria with highest emulsification potential were selected to be the best biosurfactant producer. Results: Result of the haemolytic activity test on blood agar showed that 46 isolates (17.4%) out of the 264 isolates showed beta-hemolytic activity, 39 (84.8%) isolates out of the 46 beta haemolytic isolates were positive for oil spreading test, 33 (84.6%) isolates were positive to the drop collapse  assay and all the seventeen highly positive isolates for drop collapse test were positive  for BATH test. Pseudomonas taenensis had the highest E.I of 71.05% at 24 hrs while Acinetobacter calcoaceticus had the lowest E.I of 32.6% at 24 hrs. Isolates with highest E. I were chosen to be best biosurfactant producer and are the best choice of isolate to produce biosurfactant. Conclusion: The present study inferred that bacterial strains of Pseudomonas taenensis showed satisfactory results in all the screening tests and can be used as a potential candidates for biosurfactant and bioemulsion production.