Bacterial community dynamics during bioremediation of diesel oil-contaminated Antarctic soil

S. VÁZQUEZ; B. NOGALES; L. RUBERTO; E. HERNANDEZ; J. CHRISTIE-OLEZA; A. LO BALBO; R. BOSCH; J. LALUCAT; W. MAC CORMACK

MICROBIAL ECOLOGY

Springer New York

Lugar: New York; Año: 2009 vol. 57 p. 598 - 610

0095-3628

The effect of nutrient and inocula amendment ina bioremediation field trial using a nutrient-poor Antarcticsoil chronically contaminated with hydrocarbons wastested. The analysis of the effects that the treatments causedin bacterial numbers and hydrocarbon removal was combinedwith the elucidation of the changes occurring on thebacterial community, by 16S rDNA-based terminal restrictionfragment length polymorphism (T-RFLP) typing, andthe detection of some of the genes involved in thecatabolism of hydrocarbons. All treatments caused asignificant increase in the number of bacteria able to growon hydrocarbons and a significant decrease in the soilhydrocarbon content, as compared to the control. However,there were no significant differences between treatments.Comparison of the soil T-RFLP profiles indicated that therewere changes in the structure and composition of bacterialcommunities during the bioremediation trial, although thecommunities in treated plots were highly similar irrespectiveof the treatment applied, and they had a similartemporal dynamics. These results showed that nutrientaddition was the main factor contributing to the outcome ofthe bioremediation experiment. This was supported by thelack of evidence of the establishment of inoculatedconsortia in soils, since their characteristic electrophoreticpeaks were only detectable in soil profiles at the beginningof the experiment. Genetic potential for naphthalenedegradation, evidenced by detection of nahAc gene, wasobserved in all soil plots including the control. In treatedplots, an increase in the detection of catechol degradationgenes (nahH and catA) and in a key gene of denitrification(nosZ) was observed as well. These results indicate thattreatments favored the degradation of aromatic hydrocarbonsand probably stimulated denitrification, at leasttransiently. This mesocosm study shows that recovery ofchronically contaminated Antarctic soils can be successfullyaccelerated using biostimulation with nutrients, and that thiscauses a change in the indigenous bacterial communities andin the genetic potential for hydrocarbon degradation.