Experimental and Mathematical Methodology on the Optimization of Bacterial Consortium for the Simultaneous Degradation of Three Nitrogen Heterocyclic Compounds

Abstract

This study aims to establish a systematic method to optimize the bacterial consortium for the simultaneous biodegradation of multixenobiotics in wastewater. Three nitrogen heterocyclic compounds (NHCs), pyridine, quinoline, and carbazole, were chosen as the target compounds with each about 200 mg/L. Different consortia originated from six bacteria for degrading pyridine (Paracoccus sp. BW001 and Shinella zoogloeoides BC026), quinoline (Pseudomonas sp. BW003 and BW004), and carbazole (Pseudomonas sp. BC039 and BC046) were tested for the capacity of NHCs simultaneous degradation. Mathematical methods including dummy-variable-laden kinetic modeling, cubic spline regression and interpolation, and dimensionality reduction were employed to evaluate the complex impacts of cocontaminants and coexisting bacteria on the simultaneous biodegradation, and the most efficient consortium was determined. The influences of cocontaminants on the bacterial degradation activity were far greater than the interactions among the mixed bacteria. Integrating the experimental results and mathematical analysis, consortium M19 (BC026, BW004, BC039, and BC046 with dose rate of 1:1:0.5:0.5) was the best one, which degraded over 95% of pyridine, quinoline, and carbazole simultaneously in 15.4 h. The research methodology in this study could be applied to the optimization of a bacterial consortium which might be used in the bioaugmentation and bioremediation of multixenobiotics removal.