Isolation and characterization of bacteria with potential naphthalene-degradation form “La Escondida” lagoon, Reynosa, Mexico

Abstract

Bioremediation, is currently one of the most studied techniques for the elimination of polycyclic aromatic hydrocarbons in soils. However, in order to have a more efficient degradation process, the use of autochthonous bacteria from the contaminated region is recommended because these bacteria are adapted to the climatic and environmental conditions of the site to be remedied. The aim of this work was to isolate and characterize bacteria strains from the city of Reynosa, Mexico, with the potential to degrade naphthalene. Strain isolation was carried out whit soil samples from the shore of“La Escondida” lagoon, a former landfill of pollutants of the petrochemical industry. The isolates were subjected to the emulsion index test as a selective factor to later evaluate their effect in the drop collapse, drop displacement and naphthalene tolerance tests. Finally, sixty-two strains were identified by amplification of the 16S rRNA gene. Ten strains showed the best values in the drop collapse, oil displacement and naphthalene tolerance tests. Four strains had the best naphthalene degradation potential; Pseudomonas aeruginosa (1P2 and 5P2), Bacillus cereus (5S1) and Bacillus subtillis (P52). A degradation of naphthalene was observed in the IR spectrum and UPLC chromatogram after 12 days by 1P2 strain.