Safety evaluation of a heavy oil-degrading bacterium, Rhodococcus erythropolis C2

The safety of an oil-degrading bacterium, C2 strain, was evaluated for utilization in an open system for bioremediation of oil-contaminated environments. The C2 strain was identified as Rhodococcus erythropolis by performing an alignment analysis of the whole 16S rRNA sequence. R. erythropolis was classified as a nonpathogenic (category 1) bacterium. Biological and biochemical properties of the C2 strain also confirmed its nonpathogenicity. The pathogenicity and basic ecotoxicity were studied in laboratory animals and in a variety of test species, respectively. General and inhalation toxicities were not detected; additionally, there was no evidence of skin irritation, mutagenic potential, eye irritation, skin sensitization, ecotoxicity or notable pathogenicity. The comparison of these results with human exposure levels and previously published data indicates that the C2 strain appears to be safe for utilization in bioremediation of polluted environments, requires no special occupational health precautions during the application process, and has a low environmental impact. This study suggests that the C2 strain could be suitable for bioremediation of oil-contaminated environments.