What chemical within petroleum can be used by some bacteria to create catechol and then acetyl-coa?

The answer is toluene. The hydrocarbon component is degraded by some bacteria such as Pseudomonas bacteria species. The catabolic pathway in the bacteria adds two hydroxyl groups to toluene to form cis-toluene dihydrodiol that is later converted to 3-methylcatechol. catechol is subsequently converted to dicarboxylic acids and then follows a thiolytic cleavage to acetyl-CoA and succinate.