Diversity and biodegradation characteristics of a halophilic bacterial consortium capable of degrading BETX

A bacterial consortium capable of degrading BTEX (benzene, toluene, ethylbenzene and xylene) was developed from oil-contaminated saline soil at 30°C in 5% sea salt defined medium (SSDM). In 5% SSDM, 100 mg·L^-1 benzene could be degraded by the consortium within 56 hours, while 20-400 mg·L^-1 BTEX mixtures could be degraded within 116 hours. The biodegradation of benzene by the consortium in 5% SSDM was evaluated at different temperatures ranging from 4°C to 60°C and different pHs ranging from 6.5-9.5. The results indicated that the biodegradation of benzene occurred at a maximum rate of 42.8 μg·mL^-1·d^-1 at 30°C and pH 7.5 with 0.02% (v/v) yeast extract addition. 16S rDNA gene analysis revealed that most of the sequences from the DGGE profile of the consortium were related to halophilic genera, such as Marinobacter, Halomonas, and Alcanivorax, already known for their ability to degrade BTEX. Our results suggested that the biodegradation of BTEX by halophilic bacteria is promising for application to hypersaline conditions in the future.