Chemotaxis of halophilic bacterium Halomonas anticariensis FP35 towards the environmental pollutants phenol and naphthalene

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 FP35(T) 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 FP35(T). The results indicate that phenol (100-1,000 ppm) and naphthalene (100-500 ppm) are chemoattractants for H. anticariensis FP35(T) in a dose-dependent manner. These hydrocarbons were observed to act as chemoattractants for FP35(T) 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 beta-ketoadipate pathway for aromatic catabolism. These results suggest that H. anticariensis FP35(T) has the potential to catabolize aromatic compounds and to be used in bioremediation processes under saline conditions. (C) 2019 Elsevier B.V. All rights reserved.