Degradation of Dichlorobenzene isomers by a microbial community and a strain of Alcaligenes Xylosoxidans ssp denitrificans isolated from a polluted Aquifer

MONFERRÁN, M.V AND WUNDERLIN, D.A

Buenos Aires, Argentina.

Congreso; VI Congreso SETAC Latinoamérica; 2003

Sociedad de Toxicología y Química Ambiental

DEGRADATION OF DICHLOROBENZENES ISOMERS BY A MICROBIAL COMUNITY AND STRAIN OF Alcaligenes Xylosoxidans ssp denitrificans ISOLATED FROM POLLUTED AQUIFER   Monferran M.V., Wunderlin D.A. Universidad Nacional de Córdoba, Facultad de Ciencias Químicas, Dto. Bioquímica Clínica. Cdad. Universitaria, 5000. Córdoba, Argentina. E-mail: mmonferran@bioclin.fcq.unc.edu.ar   We report the acclimatising of a subsurface microbial community, isolated from a polluted site of Suquía river (Córdoba-Argentina), to perform the biodegradation of 1,2- 1,3- and 1,4- dichlorobenzene (DCB). Acclimation was performed during 30 days in aerobic conditions using 1,2-DCB (10 mg.L-1) as substrate. Substrate consumption was evaluated by HPLC and measuring the chloride released. Acclimated microorganisms were identified as Alcaligenes Xylosoxidans ssp denitrificans and Alcaligenes Xylosoxidans ssp Xylosoxidans. We have found that 40 mg.L-1 was the minimal concentration of 1,2-DCB that inhibit biodegradation by the acclimated microbial community. Using selective enrichment with 1,2-DCBas the sole carbon source we isolated a strain of Alcaligenes Xylosoxidans ssp denitrificans. This pure strain was able to perform the complete biodegradation of 1,2-DCBin two days affording quantitative amount of chloride. This pure strain was also tested for biodegradation of 1,3-DCB and 1,4-DCB, affording results similar to the experiments using 1,2-DCB. These results demonstrate that acclimatation procedure afford a microbial consortium that is able to perform biodegradation of 1,2-DCB. The strain Alcaligenes Xylosoxidans ssp denitrificans, isolated from this microbial community, is able to use different isomers of DCB as the only source of carbon and energy affording complete biodegradation of these xenobiótico compounds.