Phthalate-Degrading Bacteria Isolated from an Industrial Mining Area and the Processing of Potassium and Magnesium Salts

Abstract

We have identified 25 halotolerant strains of ortho-phthalic acid (OPC) decomposer bacteria from samples of soil, sludge, and bottom sediments taken in the area of salt mining enterprises of Uralkalij (Berezniki, Russia). Based on an analysis of the 16S rRNA gene, the isolates were assigned to the genera Rhodococcus, Dietzia, Bacillus, Halomonas, Pseudomonas, Idiomarina, Stappia, Martelella, Erythrobacter, Alcanivorax, Marinobacter, Oceanisphaera, Nitratireductor, and Breoghania. Eight OPC decomposer strains are capable of using the phthalic acid esters Dibutyl phthalate (DBP) and Diethyl phthalate (DEP) as the sole source of carbon and energy. The strains utilized 90–98% of DBP and 49–80% of DEP (the phthalate concentration is 500 mg/L), both in the absence of NaCl in the cultivation medium and with a concentration in the medium of 50 g/L. An increase in the NaCl concentration in the medium to 70 and 90 g/L did not significantly affect the utilization of phthalates. The ability of bacteria of the genera Halomonas, Martelella, and Oceanisphaera to decompose DEF and DBP has been shown for the first time. Isolated phthalate (OPC, DEP and DBP) decomposer strains are promising for the development of new methods for the bioremediation of saline soils contaminated with phthalates.