Interaction and biodegradation evaluate of m-cresol and quinoline in co-exist system

Abstract

Environmentally hazardous and toxic chemicals are commonly generated in actual wastewater that the complex compositions in wastewater treatment system need different types of strains to be degraded. The main objective of this research was to understand the effect of extra substrates, phenolic and N-heterocyclic compounds, on the performance of pure cultural and mixed strains under single and dual substrates conditions. Two bacteria, Lysinibacillus sp. SC03 and Achromobacter sp. DN-06, were acclimated to degrade different concentrations of m-cresol and quinoline. The results indicated that Lysinibacillus sp. SC03 could completely degrade 100 mg l−1m-cresol with no delay time, however, little removal of quinoline was observed; Achromobacter sp. DN-06 could degrade 100 mg l−1 quinoline in 32 h, but could not remove m-cresol, which means m-cresol and quinoline is the specific substrate. The degradation rate of m-cresol fitted well to the zero-order kinetic equation although the degrading ability of Lysinibacillus sp. SC03 was inhibited when less than 100 mg l−1 quinoline was added, and the inhibitive effect was confirmed to be a noncompetitive pattern which could be interpreted by the Michaelis–Menten kinetics equation with corresponding parameters Vmax, Km, K1 and K2 were 13.16 mg l−1 h−1, 35.84 mg l−1, 200.0 mg l−1 and 285.7 mg l−1, respectively. Moreover, the addition of m-cresol-degrading strain (Lysinibacillus sp. SC03) could accelerate the removal of quinoline because the metabolites of quinoline could be degraded by Lysinibacillus sp. SC03 and the chemical equilibrium moved to more biodegradation of quinoline. Also, this process attributed to less the delay time during the quinoline removal.