Surfactant Production by Epiphytic Bacteria, Lysinibacillus Sphaericus Bibi1 and Proteus Mirabilis Strain Bibi8 and their Potential for Hydrocarbon Degradation

In this study, the ability of Lysinibacillus sphaericus BiBi1 and Proteus mirabilis BiBi8 isolated from and identified using biochemical and 16S rRNA molecular typing from leaves of Celosia argentea, were tested for their ability to utilise diesel as sole carbon source and also produce surfactants. The growth dynamics of isolates on diesel over 13-day incubation on diesel mineral salt medium revealed that Strain BiBi1 grew exponentially from day 0 to Day 8, with growth reaching its peak at day 10. A gradual decrease in the pH of the medium was observed from day 0 to day 13. Proteus mirabilis had a steady growth rate on diesel from day 0 to day 10 where growth was at its peak on day 12. Bacterial strain BiBi1 and BiBi8 showed alpha and beta hemolysis on blood agar and also recorded E24 % value of 51.28 and 76.32 respectively. The surfactants produced were characterized using high performance liquid chromatography, Lysinibacillus sphaericus produced rhamnolipids and subtilis as its surface biomolecule whereas Lysinibacillus sphaericus, in addition to rhamnolipid also produced lipopeptides. The results obtained from this study shows that Lysinibacillus sphaericus strain BiBi1 and Proteus mirabilis strain BiBi8 have potential for remediation of hydrocarbon contaminated environments.