Utilization of methoxylated aromatic compounds by the acetogen Clostridium thermoaceticum: Expression and specificity of the co-dependent O-demethylating activity

The aromatic CO-dependent O-demethylating activity of Clostridium thermoaceticum was evaluated. Secondary aromatic substituent groups (-OH, -CO 2H, -CH 2OH, and -OCH 3) were critical to 0 demethylation. O-demethylating activities and specificities were similar from cells grown at the expense of different methoxylated aromatic compounds; all O-methyl-grown cells catalyzed the same sequential 0 demethylation of multi-methoxylated compounds, suggesting that a broad specificity O demethylase was involved in 0 demethylation. In cell-fractionation studies, COdependent 0 demethylation was catalyzed by membrane-associated components.