New aspects of co-regulation of decarboxylation and demethylation activities in Nocardia.

Vanillic acid at 0.2% concentration in the medium of Nocardia autotrophic DSM 43100 leads to cyclic production of guaiacol; protocatechuic and p-hydroxybenzoic acids as well as catechol appear at the same time in the medium instead of isovanillic acid, which accumulates at lower vanillic acid concentration. Transformation of catechol formed into guaiacol by methylation with formaldehyde, and successively into protocatechuic acid by carboxylation seems possible. Successive reactions of methylation/demethylation and carboxylation/decarboxylation result in cyclic production of guaiacol.