No abstract

The aim of this study was evaluate the effect of bioaugmentation by free and immobilized strains of microbial consortium on the phytoremediation of polychlorinated biphenyl (PCB)-contaminated soil using the Avena sativa, Brachiaria decumbens, Brassica juncea, and Medicago sativa plants. Alginate and biochar were used as carrier materials and free cells were used as the control. PCBs 44, 66, 118, 138, 153, 170, and 180 were chosen as indicator PCB congeners. After 60 days of plant growth, the concentration of each congener and the survival of the microbial inoculum were evaluated. The removal of the PCB congener was greater in Brassica juncea planted treatments and using biochar as a carrier material. PCB 66 was the congener with the highest removal percentage in all using biochar and alginate-immobilized microorganisms and free microorganisms, while PCB 170 had the lowest removal percentage in all treatments. The largest removal percentage for all congeners was obtained using biochar as a carrier material (7.2% to 30.3%) and the lowest with planted treatments using free Downloaded by [University of California, San Diego] at 07:15 28 March 2016 ACCEPTED MANUSCRIPT ACCEPTED MANUSCRIPT3 microorganisms (2.3% to 6.8%). Real-time polymerase chain reaction (PCR) showed that the microbial inoculum survived when it was immobilized using both alginate and biochar without any significant differences between treatments; however, PCB removal percentages were obtained with biochar, which demonstrated that this carrier material has a positive effect on microbial activity.

En este trabajo se aislaron dos microorganismos con capacidad de degradar “capacidad de degradar policlorobifenilos (PCB)”, a partir de suelo contaminado y se evaluó su efecto como inoculo para realizar bioaumentación con el fin de recuperar suelos contaminados con PCB. Los microorganismos fueron identificados como Pseudomonas spp. y Stenotrophomonas spp. Se determinó su capacidad de degradar PCB usando los congéneres 44, 66, 118, 138, 153, 170 y 180. En medio líquido usando los PCB como fuente de carbono, se obtuvo porcentajes de degradación de 37%, 32,6% y 15% para los PCB 44, 66 y 118. En los ensayos de bioaumentación se utilizó suelo estéril y suelo no estéril, obteniéndose mayores porcentajes de degradación para todos los congéneres en el suelo estéril, lo cual demostró el efecto negativo de la microbiota autóctona sobre el inoculo adicionado.