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Immobilization of Ochrobactrum tritici As5 on PTFE thin films for arsenite biofiltration

Branco, Rita, Sousa, Tânia, Piedade, Ana P., Morais, Paula V.
Chemosphere 2016 v.146 pp. 330-337
Gibbs free energy, Ochrobactrum tritici, arsenic, arsenites, bacteria, biofilm, biofilters, biofiltration, bioremediation, hydrophobicity, immobilized cells, mutants, toxicity, transporters, zeta potential
Ochrobactrum tritici SCII24T bacteria is an environmental strain with high capacity to resist to arsenic (As) toxicity, which makes it able to grow in the presence of As(III). The inactivation of the two functional arsenite efflux pumps, ArsB and ACR3_1, resulted in the mutant O. tritici As5 exhibiting a high accumulation of arsenite. This work describes a method for the immobilization of the mutant cells O. tritici As5, on a commercial polymeric net after sputtered modified by the deposition of poly(tetrafluoroethylene) (PTFE) thin films, and demonstrates the capacity of immobilized cells to accumulate arsenic from solutions. Six different set of deposition parameters for PTFE thin films were developed and tested in vitro regarding their ability to immobilize the bacterial cells. The surface that exhibited a mild zeta potential value, hydrophobic characteristics, the lowest surface free energy but with a high polar component and the appropriate ratio of chemical reactive groups allowed cells to proliferate and to grow as a biofilm. These immobilized cells maintained their ability to accumulate the surrounding arsenite, making it a great arsenic biofilter to be used in bioremediation processes.