Aerobic decolorization of Acid Brilliant Scarlet GR by microbial community and the community dynamics during sequencing batch processes

Abstract

In this research, aerobic decolorization of Acid Brilliant Scarlet GR by microbial community was studied. Effects of conditions and dye concentraion on decolorization processes were investigated. Additionally, continuous decolorization was evaluated through sequencing batch tests and the microbial dynamics during this process was analyzed by polymerase chain reaction-denaturing gradient gel electrophoresis. The results showed that 100 mg l⁻¹ of the dye was completely decolorized within 12 h, which was mainly caused by biodegradation. The optimal decolorization conditions were as follows: inoculation size 2.07 g l⁻¹ (wet cell pellet), rotation speed 150 r min⁻¹, pH 5.0-7.0 and 30 °C. The processes were well described by zero-order kinetics, and more than 700 mg l⁻¹ of the dye would inhibit the activity of the consortium. Furthermore, the microbial community exhibited high efficiency in sequencing batch processes for continuous decolorization. Microbial community structure shifted obviously when exposed to higher concentration of the dye (500 mg l⁻¹), and all the dominant microorganisms were affiliated with four different phyla of Actinobacteria, Bacteroidetes, Proteobacteria and Firmicutes.