Stability and Optimization of Biosurfactant Production by Enterobacter Cloacae AYF1

Abstract

Biosurfactants are diverse and heterogeneous group of microbial metabolites produced by certain bacteria and fungi that have both hydrophilic and hydrophobic components. This work was aimed at assessing the production, stability and optimization of rhamnolipid biosurfactant production conditions by Enterobacter cloacae AYF1 strain. Biosurfactant production, extraction, purification and optimization of the production conditions were assessed in mineral salt medium followed by stability tests under different ranges of pH, temperatures and salts concentrations using standard procedures. Gas chromatography mass spectroscopy (GC-MS) was used in characterizing the biosurfactant produced. One factor at a time (OFAT) optimization studies revealed that production of biosurfactant by Enterobacter cloacae AYF1 was optimal at 3% carbon source concentration (1.5mg/ml), pH 7.5 (1.7mg/ml), temperature 40ºC (1.8mg/ml) and incubation time of 96hrs (1.96mg/ml). The biosurfactant produced was characterized using gas chromatography mass spectroscopy (GC-MS). The results revealed the presence of different fatty acids at different peaks. This indicates that the production of rhamnolipid biosurfactant was optimal at the carbon concentration, pH, temperature and incubation time of 3%, 7.5, 40 ºC and 96hrs respectively. There is the need to use biotechnological approaches with a view to improving the performance of the bacterial strain.