Synergistic Effect of the Microbial Consortium Degrading Polycyclic Aromatic Hydrocarbons

The synergistic effect of microbial consortium S3 (including S3-1, S3-2, S3-3 and S3-4), which has the ability of degrading Polycyclic Aromatic Hydrocarbons was studied by solid phenanthrene as the sole source of carbon and energy. The research showed that only S3-1 had the characteristics of phenanthrene-degrading and other three strains could use the metabolites of S3-1 in different degree. It was found that S3-3 had the distinct ability of producing biosurfactants. The microbial consortium S3 had a faster degradation rate compared with S3-1, it was conjectured that there were two reasons: (1) other three strains might reduce the inhibitory action by using their metabolites and promote the degradation rate of phenanthrene; (2) the biosurfanctants secreted by S3-3 advanced the phenanthrene uptake by S3-1. The biosurfactants in broth could emulsify crude oil and make the surface tension of fermentation broth decrease from 45.76 to 29.67 mN/m. Preliminary identification of the biosurfactants by TLC and FT-IR indicated that it might be rhamnolipid.