Surfactant-induced bacterial community changes correlated with increased polycyclic aromatic hydrocarbon degradation in contaminated soil

Abstract

Bioremediation as a method for removing polycyclic aromatic hydrocarbons (PAHs) from contaminated environments has been criticized for poor removal of potentially carcinogenic but less bioavailable high-molecular-weight (HMW) compounds. As a partial remedy to this constraint, we studied surfactant addition at sub-micellar concentrations to contaminated soil to enhance the biodegradation of PAHs remaining after conventional aerobic bioremediation. We demonstrated increased removal of 4- and 5-ring PAHs using two nonionic surfactants, polyoxyethylene(4)lauryl ether (Brij 30) and polyoxyethylene sorbitol hexaoleate (POESH), and analyzed bacterial community shifts associated with those conditions. Eight groups of abundant bacteria were implicated as potentially being involved in increased HMW PAH removal. A group of unclassified Alphaproteobacteria and members of the Phenylobacterium genus in particular showed significantly increased relative abundance in the two conditions exhibiting increased PAH removal. Other implicated groups included members of the Sediminibacterium, Terrimonas, Acidovorax, and Luteimonas genera, as well as uncharacterized organisms within the families Chitinophagaceae and Bradyrhizobiaceae. Targeted isolation identified a subset of the community likely using the surfactants as a growth substrate but few of the isolates exhibited PAH-degradation capability. Isolates recovered from the Acidovorax and uncharacterized Bradyrhizobiaceae groups suggest the abundance of those groups may have been attributable to growth on surfactants. Understanding the specific bacteria responsible for HMW PAH removal in natural and engineered systems and their response to stimuli such as surfactant amendment may improve bioremediation efficacy during treatment of contaminated environmental media.

Application of surfactants and biosurfactants in the bioremediation of multi-contaminated soils: microcosms and bench scale bioreactor trials

“…This indicates that a considerable part of the community has been affected by the addition of different surfactants. Increased Proteobacteria in surfactant-containing samples has been observed previously and correlated with increased pollutant removal [39,40]. This increase was due to increased hydrocarbon contact with hydrocarbonoclastic populations [39].…”

“…Increased Proteobacteria in surfactant-containing samples has been observed previously and correlated with increased pollutant removal [39,40]. This increase was due to increased hydrocarbon contact with hydrocarbonoclastic populations [39]. However, a PCoA analysis indicated that Sphingobacteria had a stronger association with surfactant containing samples than the Proteobacteria OTUs.…”

Moderate-Intensity Exercise Affects Gut Microbiome Composition and Influences Cardiac Function in Myocardial Infarction Mice

“…These bacteria were reported to reside primarily in the surrounding environment. However, few reports have explored the effects and roles of these bacteria in heart disease ( Singleton et al, 2016 ). A possible explanation for the alterations observed in this study is that impaired cardiac function results in intestinal ischemia and changes in the composition of the microbiota and vice versa.…”

Natural Purification Through Soils: Risks and Opportunities of Sewage Effluent Reuse in Sub-surface Irrigation

“…Thus, in the absence of accounting for such additional interactions, basing mobility on pH dependent D oc or S water represents a maximum assumption for mobility (Schulze et al 2018). Accordingly, prolonged sorption may lead to microbial responses such as the formation of biofilms (Adrion et al 2016;Bezza and Chirwa 2017;Singleton et al 2016). Biofilms can reach thicknesses of multiple centimeters.…”