The kinetics of naphthalene-2-sulfonic acid (2-NSA) adsorption by granular activated carbon (GAC) were measured and the relationships between adsorption, desorption, bioavailability and biodegradation assessed. The conventional Langmuir model fitted the experimental sorption isotherm data and introduced 2-NSA degrading bacteria, established on the surface of the GAC, did not interfere with adsorption. The potential value of GAC as a microbial support in the aerobic degradation of 2-NSA by Arthrobacter globiformis and Comamonas testosteroni was investigated.
View Article and Find Full Text PDFA soil suspension was used as a source to initiate the development of microbial communities in flow cells irrigated with 2,4-dichlorophenoxyacetic acid (2,4-D) (25 microg ml(-1)). Culturable bacterial members of the community were identified by 16S rRNA gene sequencing and found to be members of the genera Pseudomonas, Burkholderia, Collimonas and Rhodococcus. A 2,4-D degrading donor strain, Pseudomonas putida SM1443 (pJP4::gfp), was inoculated into flow cell chambers containing 2-day old biofilm communities.
View Article and Find Full Text PDFDegradation of a synthetic tanning agent CNSF (a condensation product of 2-naphthalenesulfonic acid (2-NSA) and formaldehyde) by four activated sludges, two previously characterised bacterial strains, Arthrobacter sp. 2AC and Comamonas sp. 4BC, and the fungus Cunninghamella polymorpha, was studied in batch culture at 25 degrees C by determining the changes in the concentrations of CNSF and its component monomers and oligomers (n2-n11).
View Article and Find Full Text PDFTwo bacterial strains, 2AC and 4BC, both capable of utilizing naphthalene-2-sulfonic acid (2-NSA) as a sole source of carbon, were isolated from activated sludges previously exposed to tannery wastewater. Enrichments were carried out in mineral salt medium (MSM) with 2-NSA as the sole carbon source. 16S rDNA sequencing analysis indicated that 2AC is an Arthrobacter sp.
View Article and Find Full Text PDFEnhanced biodegradation of organic xenobiotic compounds in the rhizosphere is frequently recorded although the specific mechanisms are poorly understood. We have shown that the mineralization of 2,4-dichlorophenoxyacetic acid (2,4-D) is enhanced in soil collected from the rhizosphere of Trifolium pratense[e.g.
View Article and Find Full Text PDFPesticides in soil are subject to a number of processes that result in transformation and biodegradation, sorption to and desorption from soil components, and diffusion and leaching. Pesticides leaching through a soil profile will be exposed to changing environmental conditions as different horizons with distinct physical, chemical and biological properties are encountered. The many ways in which soil properties influence pesticide retention and degradation need to be addressed to allow accurate predictions of environmental fate and the potential for groundwater pollution.
View Article and Find Full Text PDFAppl Environ Microbiol
August 2004
Enhanced biodegradation in the rhizosphere has been reported for many organic xenobiotic compounds, although the mechanisms are not fully understood. The purpose of this study was to discover whether rhizosphere-enhanced biodegradation is due to selective enrichment of degraders through growth on compounds produced by rhizodeposition. We monitored the mineralization of [U-(14)C]2,4-dichlorophenoxyacetic acid (2,4-D) in rhizosphere soil with no history of herbicide application collected over a period of 0 to 116 days after sowing of Lolium perenne and Trifolium pratense.
View Article and Find Full Text PDFWe developed a joint bioaugmentation and biostimulation approach for the clean up of soil contaminated with high (168.7 and 337.4 microg g(-1)) concentrations of the herbicide atrazine (2-chloro-4-(ethylamino)-6-isopropylamino-s-triazine).
View Article and Find Full Text PDFAppl Environ Microbiol
December 2003
Pseudomonas sp. strain ADP uses the herbicide atrazine as the sole nitrogen source. We have devised a simple atrazine degradation assay to determine the effect of other nitrogen sources on the atrazine degradation pathway.
View Article and Find Full Text PDFThe chemical structure and composition of a retan agent, CNSF (condensation product of naphthalenesulfonic acid (NSA) and formaldehyde), and related components contained in tannery wastewaters were analyzed by ion-pair liquid chromatography coupled to electrospray ionization mass spectrometry (IPC-HPLC/ESI-MS) in negative ion mode. This method allows high-resolution separation of polymers. CNSF contained linear NSA oligomers (n = 1-11) that were eluted in order of increasing degree of polymerization.
View Article and Find Full Text PDFThe effect that culture methods have on the diversity of degradative microbial communities is not well understood. We compared conventional batch enrichment with a biofilm culture method for the isolation of polycyclic aromatic hydrocarbon (PAH)-degrading microbial communities from a PAH-contaminated soil. The two methods were assessed by comparing: (i) the diversity of culturable bacteria; (ii) the diversity of PAH-catabolic genes in isolated bacteria; (iii) the inter- and intraspecific diversity of active PAH-catabolic gene classes; (iv) the diversity of bacteria present in 16S rRNA gene libraries generated from RNA extracted from the two communities and soil; and (v) the estimated diversity of active bacteria in the soil and culture systems.
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