Mobilization of hydrophobic contaminants from soils by enzymatic depolymerization of soil organic matter.
The effect of hydrolytic exoenzymes on the release of hydrophobic organic contaminants (HOC) from two different surface soils was studied in laboratory batch experiments. Incubation of the soils with cellulase with an activity fivefold above the inherent soil activity enhanced the release of hydrophobic contaminants (polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCB) and hydroxylated PCB) by 40-200%. Xylanase and invertase did not show measurable effects at comparable relative activity levels. This suggests that cellulose substructures are important for the retention of HOC in soil organic matter (SOM). Hydrolytic exoenzymes, and the microorganisms that release them, contribute to the mobilization of HOC from soil, by shifting the sorption equilibrium in the course of SOM transformation into dissolved organic matter or by facilitating HOC diffusion as a consequence of reduced rigidity of SOM. We conclude that not only biodegradation but also sorption and desorption of HOC in soil can be influenced by (micro-) biology and the factors that determine its activity.
Wicke
Daniel
D
Department of Water Quality Control, Technical University Berlin, Sekr KF 4, Strasse des 17, Juni 135, 10623 Berlin, Germany.
Reemtsma
Thorsten
T
D000327:Adsorption; D001673:Biodegradation, Environmental; D002480:Cellulase / Q000378:metabolism*; D043364:Endo-1,4-beta Xylanases / Q000378:metabolism; D057927:Hydrophobic and Hydrophilic Interactions; D011078:Polychlorinated Biphenyls / Q000737:chemistry / Q000378:metabolism*; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry / Q000378:metabolism*; D015203:Reproducibility of Results; D012987:Soil; D012989:Soil Pollutants / Q000737:chemistry / Q000378:metabolism*; D043324:beta-Fructofuranosidase / Q000378:metabolism
D011084:Polycyclic Aromatic Hydrocarbons; D012987:Soil; D012989:Soil Pollutants; D011078:Polychlorinated Biphenyls; D043324:beta-Fructofuranosidase; D002480:Cellulase; D043364:Endo-1,4-beta Xylanases