Formation of Dimethylmuconolactones from Dimethylphenols by Alcaligenes eutrophus JMP 134

2,3-, 2,4-, 2,5-, 3,4-, and 3,5-dimethylphenols were cometabolized by 2,4-dichlorophenoxyacetate-grown Alcaligenes eutrophus JMP 134 or the constitutive derivative JMP 134-1 via the ortho pathway into dimethylmuconolactones as dead-end products. Formation of two distinct lactones from 3,4-dimethylphenol is indicative of 2- as well as 6-hydroxylation. Induction of the meta-cleavage pathway by 2,3- and 3,4-dimethylphenols resulted in growth and no accumulation of products. In contrast, 3,5-dimethylphenol is not metabolized by the meta-cleavage pathway.