Bacterial Diversity and Aerobic Biodegradation Potential in a BTEX-Contaminated Aquifer

Abstract

In order to gain insight into the community structure and the biodegradative potential of bacteria residing in a BTEX-contaminated field site, with benzene as main pollutant, an investigation strategy with a variety of cultivation-independent and -dependent approaches was undertaken. Based on 16S ribosomal DNA sequence analysis, sampling stations in the center of the pollution plume were found to be dominated by a bacterial consortium affiliated with various members of the class of Proteobacteria and Firmicutes, including different sporulating and nonsporulating sulfate-reducing bacteria and members of the genus Geobacter. Non-polluted samples retrieved from outside the plume revealed several phylotypes which were also observed in the centre of the plume.Bacterial sequences retrieved from the fringe of the plume were dominated by several genera of beta Proteobacteria subclass which were not associated with other phylotypes obtained in this study. All sampling stations were tested positive for catechol 2,3-dioxygenase genes, indicating the presence of microorganisms with the genetic potential degrading aromatic compounds via the meta-cleavage pathway.The groundwater system at the down-gradient edge of the plume was characterized, in contrast to all other sampling stations in the center and outside the plume, by high numbers of cultivable bacteria and cultivable aerobic benzene and toluene degraders. These findings are also in accordance with the investigations based on fluorescent in situ hybridization (FISH) with rRNA-targeted oligonucleotide probes, suggesting the presence of an actively benzene degrading bacterial community of beta Proteobacteria at the fringe of the pollution plume.

Novel aerobic benzene degrading microorganisms identified in three soils by stable isotope probing

“…In another study, the majority of 81 BTEX degrading isolates from a contaminated site were Actinobacteria or Proteobacteria, the Actinobacteria were mainly Rhodococcus and Arthrobacter strains and the Proteobacteria were mainly c-Proteobacteria (more specifically Pseudomonas) (Hendrickx et al 2006). Similarly, studies involving molecular approaches to investigate benzene degrading communities have also reported the presence of microorganisms in the phyla Proteobacteria and Actinobacteria at contaminated sites (Aburto et al 2009;Alfreider and Vogt 2007;Fahy et al 2008a;Fahy et al 2006;Hendrickx et al 2005). For example, in a study involving in situ mesocosms within a BTEX contaminated groundwater plume, 16S rRNA gene analyses of mesocosm and aquifer samples indicated the communities consisted primarily of Proteobacteria (mostly fluorescent Pseudomonas) (Hendrickx et al 2005).…”

“…For example, in a study involving in situ mesocosms within a BTEX contaminated groundwater plume, 16S rRNA gene analyses of mesocosm and aquifer samples indicated the communities consisted primarily of Proteobacteria (mostly fluorescent Pseudomonas) (Hendrickx et al 2005). Likewise, the bacterial community at the edge of a BTEX plume was dominated (based on 16S rRNA gene sequences) by several genera of b Proteobacteria (Alfreider and Vogt 2007).…”

Efficiency of refinery sludge biodegradation using municipal wastewater and activated sludge and effect of hydrocarbon concentration on culturable bacteria community

“…All these biological processes, whether in continuous mode, batch mode or feed batch mode, have indicated that the rate of hydrocarbon biodegradation depends on several factors (Maki et al 1999;Tellez et al 2002;Chavan and Mukhreji 2008;Volpe et al 2009). Factors other than temperature, pH and dissolved oxygen are critical for a successful biodegradation process: these are essentially the competence of the inoculum used, the concentration of hydrocarbon and nutrients levels in the biodegradation medium (Rahman et al 2002;Tellez et al 2002;Margesin et al 2007;Hui et al 2007;Alfreider and Vogt 2007;Shokrollahzahed et al 2008).…”

Metagenômica comparativa e perfil metabólico in silico de solos no município de Cubatão, SP.

“…Microorganisms from these families have not been reported to degrade aromatic substances, but they have been found in contaminated sites in association with microorganisms known to degrade aromatic substances [3,[44][45][46][47][48].…”

“…The contamination can occur by leakage from diverse sources, such as storage tanks, transportation pipes, and gas stations. Due to the highly solubility in water BTEX can spread easily into environment, contaminating the soil, water and air [3][4][5][6]. The toxicity of BTEX in human beings has been well studied.…”