An innovative bioremediation strategy using a bacterial consortium entrapped in chitosan beads

Abstract

This aim of this work was to develop a bioremediation strategy for oil-contaminated mangrove sediments using chitosan beads containing an immobilised hydrocarbonoclastic bacterial consortium. The consortium composed of 17 isolates was obtained from an enrichment culture. The isolates were identified by 16S rDNA sequencing, which revealed 12 different genera. Thirteen isolates showed resistance to chitosan and were thus able to be trapped in chitosan beads for microcosm evaluation. The data revealed that entrapped consortium grew in the microcosms until day 15, which is when the beads disintegrated and released their biomass into the sediments. Bacterial bioaugmentation within the sediments was confirmed by cell counts; additionally, the dynamics of the bacterial populations were analysed through denaturing gradient gel electrophoresis. The chitosan showed a prebiotic effect on the autochthonous bacterial communities. Therefore, chitosan beads containing selected immobilised bacteria attain two bioremediation purposes, bioaugmentation and biostimulation, and thus represent an emergent approach.

Keywords: Bacterial consortium; Bioaugmentation; Biostimulation; Chitosan; Mangrove.