CATABOLISM OF PHENOL AND BENZOATE BY AZOSPIRILLUM STRAINS

The ability to degrade phenol and benzoate under aerobic conditions in the presence of yeast extract was studied for 31 strains of Azospirillum brasilense and Azospirillum lipoferum isolated from the rhizosphere and the rhizoplane of different plants. Twelve strains (i.e. 38%) were found to degrade one of the compounds; nine (28%) degraded benzoate, and three (10%) degraded phenol. No species specificity was found, and there was no correlation between the origin of strains and the ability to degrade phenol and benzoate. In both Azospirillum species, the metabolism of benzoate and phenol was dependent on the presence of yeast extract. Thus, only two strains degraded benzoate in the absence of yeast extract, and this was not accompanied by culture growth. No strains metabolized phenol in the absence of yeast extract. Based on the data obtained, the ability of Azospirillum spp. to degrade other aromatic compounds is proposed.