Effective removal of naphthalene from contaminated soil using halotolerant bacterial strains and vermiremediation techniques

Abstract

ABSTRACT The marine environment poses a serious threat due to accidental oil spill and industrial discharge specifically from refineries which has become a serious threat to the marine ecosystem. Most of the recalcitrant compounds belong to the group of polyaromatic hydrocarbons. Hence, the present study focuses on biodegradability of simple Polycyclic Aromatic Hydrocarbon (PAH) such as Naphthalene using halotolerant bacterial consortium isolated from oil-spilled environment. Two halotolerant bacterial consortiums were isolated based on the degradation of PAH which measured to be 69.38% by RSKVG1 and 30.61% by RSKVG2 after 96 hours. Naphthalene utilisation was up to 100 mg/L by RSKVG1 and 300 mg/L by RSKVG2. Further, the isolates were optimised for different parameters, optimum NaCl concentration was 30 g/L and 50 g/L by RSKVG1 and RSKVG2, respectively. The functional groups and secondary metabolites produced by the bacterial strains were characterised by FT-IR, HPLC, and GC-MS analysis. Biochemical, morphological and Molecular characterisation, and construction of phylogenetic tree was done which revealed the significant similarity of RSKVG1 and RSKVG2 to Bacillus thuringiensis and Bacillus pacificus respectively. The Naphthalene was also studied for the degradation using the vermiremediation technique.