Broad Coal Tar Biodegradative Potential of Rhodococcus erythropolis B10 Strain Isolated from Former Gasworks Site

Abstract

Coal carbonization by-products contain up to 10,000 aliphatic and aromatic compounds. Many of them show toxic, mutagenic, and carcinogenic character. In this study, we examined 51 pure bacterial cultures of their ability of coal tar constituent biodegradation. Bacterial cultures were isolated from both explosives and coal tar-contaminated areas. Among all of the investigated strains, 19 showed biodegradative activity. One of the isolates degraded 40% of the substrate in 14 days at a temperature of 15°C. The most active strain was identified by both classic and 16S ribosomal DNA sequencing methods and designated Rhodococcus erythropolis B10. The biodegradation of coal tar constituents, performed by identified strain, was assessed by GC/MS technique. The comparison of samples analyzed by GC/MS before and after biodegradation indicated high degradative potential of the chosen strain. It was able to degrade n-paraffins, n-olefins, benzene, alkylbenzenes, cadalene, and other PAHs, as well as recalcitrant heterocyclic compounds dibenzofuran and its methyl-substituted derivative. The B10 strain isolated and tested in this research shows promising possibilities to be used in field conditions. The biodegradation experiments indicated that satisfactory results may be obtained even in pure bacterial cultures.