Molecular characterization of linear alkylbenzene sulphonate degrading <i style="mso-bidi-font-style:normal">Pseudomonas nitroreducens</i> (MTCC 10463) and <i style="mso-bidi-font-style:normal">P. aeruginosa </i>(MTCC 10462)

Abstract

Surfactants are surface active chemical compounds, which are extensively used in various industrial and household formulations. Now-a-days, linear alkylbenzene sulphonate (LAS) is the most important anionic surfactant in use. The biodegradability of LAS is the main reason for its acceptance as a major chemical in industrial applications. But the huge amount discharged upsets the efficient removal by biodegradation and its acute exposure pose harm to the environment. Studies on indigenous isolates capable of efficient LAS degradation were conducted and two strains of the genus <i style="mso-bidi-font-style: normal">Pseudomonas </i>showing about 81% of LAS degradation were selected. The biochemical and molecular characterization of the isolates were done in order to identify them. The selected isolates were identified as <i style="mso-bidi-font-style: normal">P. nitroreducens</i> (L9) (MTCC 10463)<i style="mso-bidi-font-style: normal"> </i>and<i style="mso-bidi-font-style:normal"> P. aeruginosa </i>(L12) (MTCC 10462). The sequences generated in the 16S rDNA analyses were deposited in the NCBI GenBank under the accession numbers HQ271083 (L9) and HQ271084 (L12). The role of plasmid in biodegradation was checked and it was found that genomic DNA and plasmid together code for the degradation capacity of the selected strains. Though the colony count was reduced at high LAS concentrations, selected isolates were able to withstand very high concentrations of LAS (12000 ppm). In the presence of an alternate carbon source, such as, dextrose, the isolate showed diauxic growth. The selected strains were found to be two promising candidates for the bioremediation of the anionic surfactant LAS.