Dissemination of Catabolic Plasmids among Desiccation-Tolerant Bacteria in Soil Microcosms
The dissemination of catabolic plasmids was compared to bioaugmentation by strain inoculation in microcosm experiments. When Rhodococcus erythropolis strain T902, bearing a plasmid with trichloroethene and isopropylbenzene degradation pathways, was used as the inoculum, no transconjugant was isolated but the strain remained in the soil. This plasmid had a narrow host range. Pseudomonas putida strain C8S3 was used as the inoculum in a second approach. It bore a broad host range conjugative plasmid harboring a natural transposon, RP4::Tn4371, responsible for biphenyl and 4-chlorobiphenyl degradation pathways. The inoculating population slowly decreased from its original level (106 colony-forming units [CFU]/g of dry soil) to approx 3 x 102 CFU/g of dry soil after 3 wk. Transconjugant populations degrading biphenyl appeared in constant humidity soil (up to 2 x 103 CFU/g) and desiccating soil (up to 104 CFU/g). The feasibility of plasmid dissemination as a bioaugmentation technique was demonstrated in desiccating soils. The écologie significance of desiccation in bioaugmentation was demonstrated: it upset the microbial ecology and the development of transconjugants.
Index EntriesBioaugmentation drought tolerance conjugation plasmid dissemination microcosm isopropylbenzene
Unable to display preview. Download preview PDF.
- 2.Rittmann, B. and Whiteman, R. (1994), Water Qual. Int. 1, 12–16.Google Scholar
- 6.Weekers, F., Jacques, P., Springael, D., Mergeay, M., Diels, L., and Thonart, P. (1996), Med. Vac. Landbouww. Univ. Gent 61/4b, 2161–2164.Google Scholar
- 7.Potts, M. (1994), Microbiol. Rev. 58, 755–805.Google Scholar
- 9.Sayler, G., Hooper, S., Layton, A., and King, J. (1990), in Microbial Ecology, Fietcher, M., ed., Springer-Verlag, New York.Google Scholar
- 11.Daane, J., Molina, J., Berry, E., and Sadowski, M. (1996), Appl. Environ. Microbiol. 62, 515–521.Google Scholar
- 13.Di Giovanni, G., Neilson, J., Pepper, I., and Sinclair, N. (1996), Appl. Environ. Microbiol. 62, 2521–2526.Google Scholar
- 17.Dabrock, B., Kesseler, M., Averhoff, B., and Gottschalk, G. (1994), Appl. Environ. Microbiol. 60, 853–860.Google Scholar
- 18.Springael, D., Kreps, S., and Mergeay, M. (1993), J. Bacterial. 175, 1674–1681.Google Scholar
- 19.Weekers, F., Jacques, P., Springael, D., Mergeay, M., Diels, L., and Thonart, P. (2000), in Focus on Biotechnology, Hofman, M. and Anne, J., eds., Kluwer Academic, Amsterdam.Google Scholar
- 20.Galli, E., Barbieri, P., and Bestteti, G. (1992), in Pseudomonas: Molecular Biology and Biotechnology, Galli, E., Silver, S., and Withold, B., eds., American Society for Micro-biology, Washington, DC.Google Scholar
- 22.Paul, E. and Clark, F. (1988), Soil Microbiology and Biochemistry, Academic Press, London.Google Scholar
- 23.Mergeay, M. and Springael, D. (1996), in Bioremediation Protocols, Sheehan, D., ed., Humana Press, Totowa, NJ.Google Scholar