Halotolerant Benzoic Acid-Degrading Bacteria of the Genus <i>Dietzia</i>

Abstract

Six benzoic acid-degrading bacteria of the genus Dietzia were isolated from the saline ecotopes of the Verkhnekamskoe and Yakshinskoe salt deposits (Perm region, Komi Republic, Russia). Benzoic acid (BA) may accumulate in ecosystems through technogenic processes, as well as during the microbiological decomposition of complex organic compounds containing an aromatic ring. The strains studied here were found to be closely related to D. psychralcaliphila, D. kunjamensis subsp. kunjamensis, D. cercidiphylli, and D. maris. It was shown that they are halotolerant and able to thrive on BA as their sole carbon and energy source in the absence of salt or in the presence of 50–70 g/L NaCl. They also contain benA genes encoding the α-subunit of benzoate 1,2-dioxygenase, the key enzyme of BA degradation. The highest level of similarity (79.32–91.38%) was observed between the nucleotide sequences of the benA genes of the strains considered and the homologous sequences of Actinomycetes representatives from genera such as Dietzia, Mycolicibacterium, Geodermatophilus, Pseudonocardia, Corynebacterium, and Raineyella. The described active BA degraders belonging to the genus Dietzia have the potential to aid in the development of bioremediation techniques for environmental objects contaminated with mono(poly)aromatic pollutants and subject to salting.