Title: Effectiveness of recombinant protein AlnA in enhancing the extractability of polychlorinated biphenyls from contaminated soils

Abstract: One of the major limitations in bioremediation of polychlorinated biphenyls (PCBs) in contaminated soils is their low water solubility and high adsorbability. In the present study, effectiveness of recombinant protein AlnA as a biosurfactant in increasing extractability of PCBs was first investigated. The AlnA surface tension measurements allowed for determination of the minimum value of 37.89 mN/m with critical micelle concentration of 1.07 g/L. The solubilization of PCBs and desorption experiments were performed. It was observed that AlnA at 20 μg/mL could enhance solubility of selected crystal PCBs varying from 1.87 to 6.12 folds and it is easier to recover PCBs from contaminated soils compared with Tween-80 and cyclodextrin. Pot experiments indicated AlnA elevated 1.4–2.1-fold PCBs accumulation in roots by Alfalfa. The homology modeling and docking revealed PCBs congeners had different interactions with AlnA and higher-chlorinated PCBs possessed higher binding affinity. Results showed AlnA had considerable application potential in remediation of PCBs pollution.