Biosorption and Transformation of Tetrachloroethylene and Trichloroethylene Using Mixed-Species Microbial Mats

Copyright 1999 Kansas State University Key words: tetrachloroethylene, trichloroethylene, partitioning, biosorption, microbial mats Microbial mats are self-sustaining, photoautotrophic assemblages of mixed-aquatic microbial species, primarily consisting of cyanobacteria. Although cyanobacteria (formerly termed blue-green algae) are neither a true algae or plant, there is significant promise for the application of microbial mats to contamination problems in a manner similar to conventional phytoremediation techniques. In recent years, microbial mats have been used to successfully treat wastewater contaminated by metals and metalloids including lead, cadmium, copper, zinc, cobalt, iron, uranium, and manganese (Bender et al., 1995a). The mats have also been shown to degrade many organic compounds including trinitrotoluene, chrysene, naphthalene, hexadecane, phenanthrene, polychlorinated biphenyl, trichloroethylene, and the pesticides chlordane, carbofuran, and paraquat (Bender et al., 1995b; Kuritz and Wolk, 1994). Recent experiments have demonstrated a significant potential for microbial mats to assimilate and transform the organic compound tetrachloroethylene (PCE) and trichloroethylene (TCE) in aqueous media (O'Niell et al., 1997 and 1998). PCE and TCE are common xenobiotic contaminants that are recalcitrant to degradation. Widespread and prolonged use of these volatile solvents in industrial applications has led to extensive contamination of soils, groundwater, and surface waters (Riley and Zachara, 1992; Westrick et al., 1984). In situ remediation technologies (e.g., natural attenuation, phytoremediation, biodegradation, reactive subsurface barriers, etc.) presently used for the removal of PCE and TCE from contaminated sites may require many decades to achieve accept..

Rizoremediação de pentaclorofenol em um solo argiloso por sphingomonas chlorophenolica ATCC 39723 Pentachlorophenol rhizoremediation in a loamy soil by sphingomonas chlorophenolica ATCC 39723

O principal objetivo deste trabalho foi estudar a degradação de PCP por Sphingomonas chlorophenolicaem solo argiloso na presença e ausência de trigo. As concentrações de PCP foram determinadas através de Análises de Alta Performance de Cromatografia Líquida. Os efeitos tóxicos de PCP foram estudados através do monitoramento do crescimento das plantas. A biodegradação de PCP por S. chlorophenolica foi acompanhada por testes de bioluminescência de Escherichia coli HB101 pUCD607 e contagens bacterianas no solo e nas raízes. A degradação de PCP ocorreu de forma mais rápida no solo plantado e inoculado quando comparada ao solo sem plantas. Houve um aumento significativo nas populações dos organismos testados nas raízes quando comparadas com as populações presentes no solo. O monitoramento do crescimento da planta mostrou o papel protetor exercido pela S.chlorophenolica contra a toxicidade do PCP.<br>The main objective of this study was study the PCP degradation by Sphingomonas chlorophenolica in a loamy soil in the presence and absence of plants (Winter wheat). Measurements of PCP concentrations were carried out in a laboratory basis using High performance liquid chromatography analysis (HPLC). The toxic effect of PCP on plants was studied through the monitoring of the plant growth. The biodegradation of PCP by S. chlorophenolica in soil was assessed with a bioluminescence assay of Escherichia coli HB101 pUCD607 and bacterial analyses in roots and soil. The planted and inoculated soil showed a faster degradation when compared to the inoculated soil without plants. There was a significative increase in the populations of the organisms tested in the roots when compared to the soil. The monitoring of the plant growth showed a protective role of S. chlorophenolica against the toxicity of PCP in the loamy soil