Bioremediation of an oxyfluorfen-polluted soil using biostimulants obtained by fermentation processes: Effect on biological properties.

We report a study of the bioremediation of two biostimulants obtained from sewage sludge by fermentation processes in a oxyfluorfen-polluted soil over a 72-day period under laboratory conditions. The effects thereof on enzymatic activities, bacterial community and the evolution of oxyfluorfen in soil are determined. At the end of the experiment, and compared with the non-polluted soil, dehydrogenase, urease, βglucosidase, and phosphatase activities in the oxyfluorfen-polluted soil decreased by 58.3%, 30.4%, 44.7%, and 48%. The application of oxyfluorfen decreased the relative abundance of the Firmicutes (24.5%) and Acidobacteria (8.3%) phyla, and increased the relative abundance of the Gaiellales order (Actinobacteria phylum). The application of both biostimulants to the soil increased the relative abundance of the Bacteroidetes, Chloroflexi and Proteobacteria phyla and decreased the relative abundance of the Acidobacteria and Actinobacteria phyla. The relative abundance of the Chloroflexi, Firmicutes and Proteobacteria phyla increased when applying the experimental biostimulants in the polluted soil. Application of both biostimulants decreased soil oxyflurofen concentration, suggesting that the use of both biostimulants with higher amounts of low molecular weight proteins and peptides could be very useful on the remediation of oxyfluorfen-polluted soils.