Enhanced degradation of hydrocarbons by gamma ray induced mutant strain of Pseudomonas putida.

Soil contamination due to petroleum hydrocarbons is a ubiquitous environmental problem for which efficient remediation alternatives are required. Application of hydrocarbons degrading bacteria with enhanced degradation potential is such an alternative. The aim of present investigation was to induce mutagenicity in Pseudomonas putida through gamma-ray irradiation for the enhanced degradation of crude oil. A total of mutant 10 bacterial strains (300A-J) were screened for their degradation abilities in vitro; among which the performance of 300-B was outstanding. Subsequently, spiked soil (30 g/kg crude oil) was augmented with the wild-type parent strain and mutant 300-B strain in individual experiments. Bacterial inoculation in both experiments enhanced hydrocarbons degradation; however, degradation was 46.3% higher when 300-B mutant strain was employed. This improved oil degradation was found to have a strong positive correlation with the gene abundance and expression of the mutant strain, suggesting its successful survival and catabolic potential in situ. Concomitantly, a better nutrients assimilation and water utilization was observed in the experiment containing 300-B mutant. Yet preliminary, these findings highlight the importance of gamma ray irradiation towards improved degradation potential of previously isolated hydrocarbons degrading bacteria.