Biodegradation of phenanthrene with biosurfactant production by a new strain of Brevibacillus sp.

In this work, a phenanthrene-degrading bacterial strain was isolated by enrichment method from hydrocarbon contaminated sludge samples and identified as Brevibacillus sp. PDM-3 based on morphological, biochemical, chemotaxonomic (FAMEs analysis) and molecular (16S rDNA sequencing) analysis. Growth parameters for efficient degradation of phenanthrene such as nutrient medium, pH, temperature, rpm and inoculum size were standardized and 93% of phenanthrene was degraded in 6 days as analysed by HPLC. The bacterial strain PDM-3 also has the ability to produce biosurfactant during phenanthrene degradation as detected by the surface tension measurements of the culture supernatant and the emulsification index (EI₂₄). The biosurfactant was identified by its functional groups through FT-IR spectroscopy. Phenanthrene degradation and biosurfactant production are associated with each other and can be used in environmental biotechnology. Further, the strain has the ability to degrade other PAHs such as anthracene and fluorene by utilizing them as sole carbon and energy source.