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Biotransformation of 4-nitrophenol by co-immobilized Geobacter sulfurreducens and anthraquinone-2-sulfonate in barium alginate beads

Rodriguez, Sujei Y., Cantú, Maria E., Garcia-Reyes, Bernardo, Garza-Gonzalez, Maria T., Meza-Escalante, Edna R., Serrano, Denisse, Alvarez, Luis H.
Chemosphere 2019 v.221 pp. 219-225
Geobacter sulfurreducens, alginates, barium, biotransformation, p-nitrophenol, pH
Geobacter sulfurreducens and anthraquinone-2-sulfonate (AQS) were used suspended and immobilized in barium alginate during the biotransformation of 4-nitrophenol (4-NP). The assays were conducted at different concentrations of 4-NP (50–400 mg/L) and AQS, either in suspended (0–400 μM) or immobilized form (0 or 760 μM), and under different pH values (5–9). G. sulfurreducens showed low capacity to reduce 4-NP in absence of AQS, especially at the highest concentrations of the contaminant. AQS improved the reduction rates from 0.0086 h−1, without AQS, to 0.149 h−1 at 400 μM AQS, which represent an increment of 17.3-fold. The co-immobilization of AQS and G. sulfurreducens in barium alginate beads (AQSi−Gi) increased the reduction rates up to 4.8- and 7.2-fold, compared to incubations with G. sulfurreducens in suspended and immobilized form, but in absence of AQS. AQSi−Gi provides to G. sulfurreducens a barrier against the possibly inhibiting effects of 4-NP.