Biodegradation of bisphenol A by bacterial consortia

The effect of light on BPA degradation by an adapted bacterial consortium was investigated. BPA was completely degraded up to 50 mg l−1, and the degradation followed first-order reaction kinetics both in the light and in the dark. The degradation half-life of BPA when the consortium was grown in presence of light was 21.9, 17.2, and 12.6 h for concentrations of 10, 20, and 50 mg l−1, respectively; the degradation half-life of BPA in the dark was 13.1, 10.8, and 10.2 h for concentrations of 10, 20, and 50 mg l−1, respectively. Therefore, light inhibited BPA biodegradation. However, under both conditions, BPA was completely depleted. The bacterial consortium effectively utilised BPA as a growth substrate to sustain a cell yield of 0.95 g g−1 and 0.97 g g−1 in the light and dark, respectively. A total of ten and nine biodegradation intermediates were detected in the light and dark, respectively. Three bacterial metabolic pathways and one photodegradation pathway were proposed to explain their occurrence. This study demonstrated that bacterial consortia may assemble a wide range of catabolic pathways to allow for efficient degradation of BPA, converting BPA to principally bacterial biomass and metabolites exhibiting low or no oestrogenic activity.