Characteristics of Rhodococcus sp. 5G1, a halotolerant dibutyl phthalate-degrading strain

Dibutyl phthalate (DBP) is one of the esters of phthalic acid, widely used as a plasticizer in the production of plastics and synthetic fibers, leading to environmental pollution. The ability of the halotolerant strain 5G1, which was isolated from the rhizosphere soil on the territory of a salt mining enterprise (Perm Krai, Russia), to use DBP as a substrate was studied. The strain was identified as representative of the genus Rhodococcus, closely related to the type strain R. erythropolis DSM43066T (similarity level of 99.6%) based on sequencing and bioinformatics analysis of the 16S rRNA gene. The halotolerant strain 5G1 can grow on DBP as a substrate and is capable of utilizing 51% DBP (0.2 g/L) by 72 h. Strain 5G1 grows on DBP at high concentrations (up to 20 g/L). A study of the presence of extrachromosomal DNA showed the presence of two plasmids in the cells of the strain with a molecular weight of ~85 kb and ~60 kb. The results obtained allow us to consider the strain Rhodococcus sp. 5G1 as promising in the biotechnology of cleaning soils and wastewaters with a complex nature of pollution.