Degradation of brilliant crocein using the halotolerant bacterial consortium DAS

Technologies for removing azo dyes from textile wastewater have attracted increasing attention. In this study, a biological method was developed using the halotolerant bacterial consortium DAS, which was isolated from an activated sludge sample. Under optimal conditions (i.e., 40℃, pH 6.0, 15% salinity and 400 mg·L−1 peptone), the degradation rate of Brilliant Crocein (BC) (500 mg·L−1 initial concentration) was 70.67 mg·L−1·h−1, with a removal percentage of 97.43±0.15% after an incubation period of 3 days. Growth-based characterizations showed that the addition of peptone as a cosubstrate facilitated degradation by enhancing metabolic activity and increasing the total bacterial biomass. 16 S rRNA-based gene analysis showed that the addition of peptone did not increase the abundance of degrading functional bacteria in the halotolerant bacterial community DAS. The degradation could be carried out in mediums with high salinity (up to 25%), enabling direct treatment of textile wastewater without the need for the dilution step. This biological method is promising for constructing an efficient and environmentally friendly technology for textile wastewater treatment. [Display omitted] •The biological method was efficient under high salinity (up to 25%).•The co-substrate peptone promoted the biodegradation of azo dye.•Adding peptone enhanced metabolic activity and increased total bacterial biomass.