Screening and biodegradation characteristics of an efficient quinoline-degrading microbial consortium

Abstract:

[Background] Quinoline, a typical nitrogen-containing heterocyclic pollutant in coking wastewater, is teratogenic, carcinogenic, and mutagenic, posing a threat to the environment. Microbial technology is environmentally friendly and efficient in the treatment of water polluted by quinoline. [Objective] To screen an efficient quinoline-degrading microbial consortium for the industrial treatment of quinoline-containing wastewater.[Methods] An efficient consortium was screened from the sludge of a coking wastewater plant by incremental stepwise domestication. The morphology was observed and the enzyme activity and substrate spectrum were tested. Then, the pH, temperature, rotational speed, loading volume, inoculum volume, and concentration of added carbon and nitrogen sources for the culture of the microbial consortium were optimized by single factor test. [Results] A consortium which can degrade 1 500 mg/L quinoline in 30 h was isolated. It can degrade a variety of nitrogen-containing heterocyclic compounds. The results of response surface methodology showed that the highest degradation rate of 66% was achieved at pH, temperature, and rotational speed of 6.8, 30 ℃, and 200 r/min, respectively. The degradation kinetic analysis revealed that the maximum specific degradation rate of 60.0 mg/(L·h) was achieved when the quinoline concentration was 1 154 mg/L. [Conclusion] The microbial consortium has a high quinolone-degrading capacity and a broad spectrum of substrates. The findings lay a basis for the industrial treatment of quinoline-containing wastewater by microorganisms.

Key words:quinoline;microbial consortium;degradation characteristics;response surface optimization;degradation kinetics