title: Nitrate-dependent biodegradation of quinoline, isoquinoline, and 2-methylquinoline by acclimated activated sludge.
abstract: The anaerobic degradation of quinoline, isoquinoline and 2-methylquinoline was investigated under nitrate-reducing conditions with acclimated activated sludge. Quinoline was completely transformed during degradation with an optimum COD/NO(3)-N ratio of 7. Isoquinoline and 2-methylquinoline were also completely transformed; however, nitrate consumption was much lower with the optimum COD/NO(3)-N ratios being in the ranges of 83-92 and 21-26, respectively. GC-MS analyses showed that during degradation, quinoline and isoquinoline were transformed by hydroxylation into 2(1H)-quinolinone and 1(2H)-isoquinolinone, respectively. While quinoline was completely mineralized, only 92% of isoquinoline was mineralized, and 1(2H)-isoquinolinone remained in the effluent. 2-Methylquinoline was transformed by hydrogenation to 1,2,3,4-tetrahydro-2-methyl-quinoline, and further degradation resulted in cleavage of the heterocyclic ring leaving 4-ethyl-benzenamine. Both the metabolites remained in the effluent, resulting in the low mineralization of 2-methylquinoline (58%). This is the first time that 2-methylquinoline is observed degradable under denitrifying conditions, and its metabolites are identified.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China. liyongmei@tongji.edu.cn
authors.forename: Yongmei
authors.initials: Y
authors.lastname: Li
authors.forename: Lin
authors.initials: L
authors.lastname: Wang
authors.forename: Lisha
authors.initials: L
authors.lastname: Liao
authors.forename: Lijuan
authors.initials: L
authors.lastname: Sun
authors.forename: Guanghong
authors.initials: G
authors.lastname: Zheng
authors.forename: Jingfei
authors.initials: J
authors.lastname: Luan
authors.forename: Guowei
authors.initials: G
authors.lastname: Gu
mesh_terms: D001673:Biodegradation, Environmental; D002852:Chromatography, Ion Exchange; D008401:Gas Chromatography-Mass Spectrometry; D007546:Isoquinolines / Q000737:chemistry*; D013058:Mass Spectrometry; D008903:Minerals / Q000032:analysis; D009566:Nitrates / Q000737:chemistry*; D010084:Oxidation-Reduction; D011798:Quinaldines / Q000737:chemistry*; D011804:Quinolines / Q000737:chemistry*; D012722:Sewage / Q000032:analysis*; D014865:Waste Disposal, Fluid
chemical_list: D007546:Isoquinolines; D008903:Minerals; D009566:Nitrates; D011798:Quinaldines; D011804:Quinolines; D012722:Sewage; C037073:2-methylquinoline; C039109:isoquinoline