There are several mechanisms.It could be by direct metabolism where the hydrocarbon serves as a energy source. It could be a tertiary metabolism or even it could be a cometabolic activity, where the microorganisms are only interested in detoxifying it for their survival.

Hi,

contact with Dr. Shayma Thyab Goa, he's worked on polyhydroxybutyrate from Bacillus cereus

The phenomenon of chemotaxis by the organisms towards the pollutants and the simultaneous attachment-detachment process maintains a constant load of biomass to the affected site in the water bodies especially or in soil. Ability to form biofilm on various surfaces is always advantageous for the microorganisms in terms of survival, metabolism, adaptation, and propagation. One of the major limitations faced in the process of bioremediation is the bioavailability of organic compounds on site. Early studies that indicate biofilm forming bacteria can be employed to overcome this limitation although the application of steady state biofilm in bioremediation is not well established. Studies indicate that biofilm-mediated bioremediation is a proficient approach and safer option since cells in biofilm have better chance of survival and adaptability especially during the stressed conditions. Physiological and proteomic studies have shown that biofilm formation is an efficient strategy to colonize hydrophobic interfaces. Marinobacter hydrocarbanoclasticus SP17 is observed to form biofilm at the interface of aqueous phase and HOC substrates like n alkanes, fatty alcohols, or polar lipids, but not on non-metabolizable compounds such as n-C32 alkanes. By dedicated co-metabolism where more than one type of organisms are present at the contaminated site and some of them practice co-metabolism (fortuitous metabolism). This is a phenomenon wherein a microorganism transforms the given compound without being able to grow on it or derive energy from it; this transformed compound can be used as a growth substrate by another microorganism present in the same environment or in a mixed culture.