Preliminary testing and design of permeable bioreactive barrier for phenanthrene degradation by Pseudomonas stutzeri CECT 930 immobilized in hydrogel matrices

BACKGROUND Currently, to allow the remediation of polluted groundwater, it is necessary to develop in situ treatments, such as permeable reactive biobarrier ( PRBB ). However, few bioreactive materials are known, and more studies are required. Therefore, the aim of this work was to obtain new bioreactive materials by immobilization of Pseudomonas stutzeri CECT 930 in different hydrogels. RESULTS To determine the effectiveness of the developed bioreactive materials phenanthrene degradation was carried out in batch assays. High degradation levels were achieved after 11 days for bacteria trapped in the different hydrogel matrices. Using experiments to test the behaviour and reusability, the performance of immobilized bacteria in continuous mode was also investigated. In these experiments, P. stutzeri immobilized in agar exhibited near complete degradation with high cell retention. Finally, this new bioreactive medium was tested in a simulated PRBB . CONCLUSION The results show that this PRBB is stable with different hydraulic retention times without operational problems or loss of activity. Therefore, the results obtained suggest the use of P . stutzeri immobilized in agar as biofiller in a PRBB for polycyclic aromatic hydrocarbon degradation in groundwater.