The inhibitory effects of four wood-derived aromatic aldehydes: vanillin, syring-aldehyde, 4-hydroxybenzaldehyde and 5-hydroxymethylfurfural were tested using Gluconobacter oxydans subsp suboxydans ATCC 621 as model organism. At low inhibitor concentrations G. oxydans was found to recover rapidly from the inhibition. The organism detoxified all the inhibitors except syringaldehyde by simultaneously oxidizing and reducing them to the corresponding acids and alcohols. The oxidation step was preferred in all cases. The enzymes responsible for the detoxification were apparently induced by the presence of the inhibitors.