Abstract

ORTIZ-MAYA, Jorge et al. BACTERIAL POPULATIONS DYNAMIC AND DEHYDROGENASE ACTIVITY DURING BIOREMEDIATION OF RECENTLY AND INTEMPERIZED HYDROCARBON CONTAMINATED SOILS. Rev. Int. Contam. Ambient [online]. 2017, vol.33, n.2, pp.237-246. ISSN 0188-4999.  https://doi.org/10.20937/rica.2017.33.02.05.

Dehydrogenase activity and composition of the native microbial community were evaluated in hydrocarbon-contaminated soil during its bioremediation by biostimulation and natural attenuation. Mesocosms-scale essays were set up, comparing conditions of recent contamination (28 days) and weathering (28-56 days) with artificially contaminated soil (30 000 mg of total petroleum hydrocarbons /kg soil). The richness of the bacterial communities was estimated based on the genomic profiles generated by denaturing gradient gel electrophoresis analysis (DGGE). In addition, populations were identified by sequencing of the dominant bands in DGGE profiles. The evolution of the biodegradation was addressed through soil dehydrogenase activity during the essays. The molecular analysis of DNA extracts revealed similar genotype richness in both newly contaminated treatments, while a significant decrease of this parameter was observed in weathered treatments. The maximum levels of enzyme activity occurred in the newly contaminated-biostimulated soil (3146.84 µg iodo-nitro-formazan (INF)/g) compared to the contaminated soil under natural attenuation (1160.19 µg INF/g). For weathered soils, dehydrogenase activity decreased compared to the other treatments. It was determined a stable over time bacterial community in the weathered soil, while the addition of nutrients favored increases of genotype richness in newly contaminated and weathered soils. Hydrocarbonoclastic bacteria (Burkholderia, Pelobacter) were identified in all sampling times in both treatments.

Keywords : enzymatic activity; DGGE; soil restoration; sequencing.

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