Halotolerant Terephthalic Acid-Degrading Bacteria of the Genus Glutamicibacter

Abstract

Terephthalic acid (TPA) is an isomer of ortho-phthalic acid, which is widely used in the chemical industry to produce artificial fibers and plastics, including polyethylene terephthalate; it is a widespread environmental pollutant. The ability of two strains of Glutamicibacter spp. PB8-1 (=ВКМ Ac-2934D) and BO25 (=ВКМ Ac2935D) isolated from the salt mining area (Perm krai, Russia) to grow using terephthalic acid as the only source of carbon and energy was studied. The strains PB8-1 and BO25 could utilize high concentrations of TPA (30 g/L), which was shown for TPA-degrading bacteria for the first time. Strains PB8-1 and BO25 were halotolerant bacteria: they grew in the NaCl-free medium or at NaCl concentrations of up to 90 g/L in a rich medium and up to 60 g/L in a mineral medium supplemented with TPA. No bacteria capable of degrading TPA under saline conditions were previously described. The growth of the strain BO25 using TPA was accompanied by the accumulation and subsequent degradation of protocatechuic acid (PCA), suggesting that the TPA metabolism occurred through PCA, which was previously described for bacteria of different taxa, including actinobacteria. Thus, TPA-degrading strains Glutamicibacter spp. PB8-1 and BO25 are promising for the development of bioremediation methods for saline soils and wastewater contaminated with TPA.