Inhibitory mechanisms by chlorobenzoate mixtures in chlorobenzoate-degrading microorganisms
- 43 Downloads
]A microbial consortium selected on 2-chlorobenzoate was shown to be able to also utilise 4-chlorobenzoate and 2,5-dichlorobenzoate as sole carbon source. The consortium adapted to grow on 4-chlorobenzoate, degraded the carbon sourcevia protocatechuate, whereas the same consortium degraded 2-chlorobenzoate and 2,5-dichlorobenzoate via 1,2- or 1,6-dioxygenation of the chlorinated ring. Moreover, no significant effects on the microbial growth due to the presence of chlorobenzoate mixtures were observed when 4-chlorobenzoate was the carbon source. Instead, when mete-substituted chlorobenzoates were added as co-substrates to 2,5-dichlorobenzoate, the growth of the consortium was totally inhibited, just as when the culture utilised for growth 2-chlorobenzoate. Uptake experiments with 2-chlorobenzoate-grown resting cells showed that 3-chlorobenzoate, 2,3-dichlorobenzoate and 2,3,5-trichlorobenzoate competed with 2-chlorobenzoate, entering the resting cells both preferentially and faster than the growth substrate, that was also impeded to enter. Also 3,4-dichlo-robenzoate and 3,5-dichlorobenzoate hindered the uptake of the growth substrate (2-chlorobenzoate and 2,5-dichlorobenzoate, respectively), but they did not enter themselves the cells. Finally, 3,5-dichlorobenzoate neither entered the 4-chlorobenzoate-grown cells nor hindered 4-chlorobenzoate uptake. The relationships between growth inhibiting effects and chlorosubstituent position on the aromatic ring of the chlorobenzoates supplied as co-substrates are discussed.
Key wordsmicrobial consortium growth inhibition chlorobenzoate mixtures uptake competition
Unable to display preview. Download preview PDF.
- Baggi G. (2000) Ecological implications of synergistic and antagonistic interactions among growth and non growth analogs present in mixture. Ann. Microbiol., 50: 103–115.Google Scholar
- Baggi G., Zangrossi M. (1995). Inhibition bymeta-substituted dichlorobenzoates inAlcaligenesdenitrificans which grows on 4-chlorobenzoate. Ann. Microbiol., 45: 185–189.Google Scholar
- Baggi G., Zangrossi M. (2001). Assessment of the biodegradative potential versus chlorobenzoates as single or mixed compounds in a stable microbial consortium. Ann. Microbiol., 51: 179–188.Google Scholar
- Stratford J., Wright M.A., Reineke W., Mokross H., Havel J., Knowles C.J., Robinson G.K. (1996). Influence of chlorobenzoates on the utilisation of chlorobiphenyls and chlorobenzoate mixtures by chlorobiphenyl/ chlorobenzoate-mineralising hybrid bacterial strains. Arch. Microbiol., 165: 213–218.CrossRefPubMedGoogle Scholar
- Stringfellow W.T., Aitken M.D. (1995). Competitive metabolism of naphthalene, metylnaphthalenes, and fluorene by phenanthrene-degrading Pseudomonads. Appl. Environm. Microbiol., 61: 357–362.Google Scholar