FIG 6.

Hypothetical model of multispecies bacterial diesel fuel biodegradation by the consortium. Hydrophobic oil droplets are first colonized by the pioneer aromatic and alkane hydrocarbon-degrading bacteria, Sphingobium and Pseudomonas, which initiate biotransformation of complex hydrocarbons by forming biofilms. The hydrocarbon biotransformation products and secondary metabolites such as biofilm matrices produced by the pioneers, which have relatively higher bioavailability, are thus utilized by other bacterial cocolonizers. These cocolonizers mainly consisted of Ochrobactrum, Achromobacter, and Cupriavidus, and their coexistence may enhance further biofilm formation and accelerate hydrocarbon biodegradation. Another major bacterial genus, Parvibaculum, was potentially responsible for biodegradation of short- and middle-chain-length alkanes and/or biphenyl-related compounds.