Chemotaxis of halophilic bacterium Halomonas anticariensis FP35T towards the environmental pollutants phenol and naphthalene

Abstract

Chemotaxis can play an important role in bioremediation and substrate bioavailability. The bioremediation of hydrocarbons in saline environments can be carried out by technologies using halophilic bacteria. The aim of this study is to analyse chemotactic responses of the halophilic bacterium Halomonas anticariensis FP35T to environmental pollutants, as well as its catabolic potential for biotechnological use in bioremediation processes under saline conditions. Chemotaxis was detected and quantified using a modified Adler capillary assay. PCR amplification with degenerate primers for genes encoding ring-cleaving enzymes was used to characterize the catabolic versatility of FP35T. The results indicate that phenol (100-1,000 ppm) and naphthalene (100-500 ppm) are chemoattractants for H. anticariensis FP35T in a dose-dependent manner. These hydrocarbons were observed to act as chemoattractants for FP35T grown in a wide range of sea salt solutions (5-12.5% (w/v). However, the 7.5% (w/v) saline concentration was found to have the strongest chemotactic response. We also detected genes encoding ring-cleaving enzymes in the β-ketoadipate pathway for aromatic catabolism. These results suggest that H. anticariensis FP35T has the potential to catabolize aromatic compounds and to be used in bioremediation processes under saline conditions.