Effect of surfactants on the solubilization, sorption and biodegradation of benzo (a) pyrene by Pseudomonas aeruginosa BT-1

In order to better understand in bioremediation of high molecular weight PAHs, the solubilization, sorption and biodegradation of benzo (a) pyrene (BaP) by Pseudomonas aeruginosa BT-1 in the presence of surfactants including Tween 80,DOSS (dioctyl sodium sulfosuccinate), rhamnolipid were evaluated. Periodically collected samples were detected by the technology of RP-HPLC (reverse phase high-performance liquid chromatograph) with FLD (Fluorescence Detector). The solubilization capacity of BaP by surfactants was followed the order: Tween 80 > Rhamnolipid > DOSS and the solubility enhancement degree (S-W*/S-W) of PAHs by Tween 80 was followed the order: BaP > Pyrene > Phenanthrene. Moreover, Tween 80 exhibited a higher sorption rate of BaP as comparison to DOSS or rhamnolipid at a low concentration (< CMC) but only DOSS played the key role at a high concentration (> CMC). When strain BT-1 was used for degrading BaP, Tween 80 also performed a higher biodegradation rate with 79.7% of BaP degraded while rhamnolipid exhibited a tow level with only 16.96%. Besides, the growth of microorganism was inhibited in DOSS supplied system, resulting in very low biodegradation rate. However, the above experimental data were all fitted to the logistic kinetic model (R-2 >= 0.97). Therefore, we concluded Tween 80 was the preferred surfactant in surfactant-enhanced bioremediation of BaP by strain BT-1. (C) 2019 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.