Growth of thermophilic acetogenic bacteria on methoxylated aromatic acids

The methoxylated aromatic acids vanillate and syringate supported the growth of Clostridium thermoaceticum and Clostridium thermoautotrophicum in an undefined culture medium (U); p-hydroxybenzoate or U did not support growth. Growth was proportional to the number of O-methyl residues on the aromatic ring and to the concentration of the methoxylated aromatic acid in U. Protein profiles, obtained by sodium dodecyl sulfate-polyacrylamide gel electrophoretic (SDS-PAGE) analysis of cell extracts from vanillate, syringate, methanol, and glucose cultures of C. thermoaceticum, indicated differential gene expression between O-methyl aromatic-, methanol- and glucose-grown cells.