Bioavailability of Soil-Sorbed Biphenyl to Bacteria

Abstract

Limited bioavailability of organic pollutants in soil may be a detriment to the successful application of bioremediation. The availability of soil-sorbed biphenyl to two biphenyl-degrading bacteria, Pseudomonas putida P106 and Rhodococcus erythropolis NY05, was assessed using a kinetic mineralization assay. Biphenyl was aged in four soils of different organic carbon (OC) contents (0.4−7.8%) for up to 274 days. With a biphenyl-soil contact time of 24 h, the initial mineralization rates (IMRs) ranged from 2.6 to 3.5 μg·L-1·min-1 for strain P106 and from 3.8 to 0.92 μg·L-1·min-1 for strain NY05. These IMRs were higher than those of soil-free controls and those predicted by a coupled desorption/biodegradation model, suggesting both strains of bacteria could access soil-sorbed biphenyl. For strain P106, biphenyl mineralization curves in slurries of four different soils were nearly coincident with those in soil-free systems containing the same total mass of biphenyl. This strain appeared to have immediate and c...