Biodegradation of petroleum by genetically engineered bacteria could be an option. Some bacteria have been shown to degrade or metabolize petroleum hydrocarbons. The acting enzymes can be purified from these microorganisms to determine the responsible gene or genes’ DNA sequence. Those isolated genes can be subject to induced mutagenesis then transferred to a model microorganism like E.coli. The model microorganisms now expresse enzymes derived from the mutated genes library. The model microorganisms can be challenged in the lab in a petroleum rich environment to see which microorganism biodegrades the best. If feasible, (such as if the enzyme is stable outside of the cells and can be mass produced), the enzyme from the selected microorganism can then be purified and used to clean-up contaminated soil.If not feasible, the microorganism expressing the effective enzyme can itself be used to clean-up the soil.

The energy we get from food goes into the cells. Synthesis consumes energy.