Accelerating Quinoline Biodegradation and Oxidation with Endogenous Electron Donors.
Quinoline, a recalcitrant heterocyclic compound, is biodegraded by a series of reactions that begin with mono-oxygenations, which require an intracellular electron donor. Photolysis of quinoline can generate readily biodegradable products, such as oxalate, whose bio-oxidation can generate endogenous electron donors that ought to accelerate quinoline biodegradation and, ultimately, mineralization. To test this hypothesis, we compared three protocols for the biodegradation of quinoline: direct biodegradation (B), biodegradation after photolysis of 1 h (P1h+B) or 2 h (P2h+B), and biodegradation by adding oxalate commensurate to the amount generated from photolysis of 1 h (O1+B) or 2 h (O2+B). The experimental results show that P1h+B and P2h+B accelerated quinoline biodegradation by 19% and 50%, respectively, compared to B. Protocols O1+B and O2+B also gave 19% and 50% increases, respectively. During quinoline biodegradation, its first intermediate, 2-hydroxyquinoline, accumulated gradually in parallel to quinoline loss but declined once quinoline was depleted. Mono-oxygenation of 2-hydroxyquinoline competed with mono-oxygenation of quinoline, but the inhibition was relieved when extra electrons donors were added from oxalate, whether formed by UV photolysis or added exogenously. Rapid oxalate oxidation stimulated both mono-oxygenations, which accelerated the overall quinoline oxidation that provided the bulk of the electron donor.
Department of Environmental Science and Engineering, College of Life and Environmental Science, Shanghai Normal University , Shanghai 200234, PR China.
Qi
Q
Bai
Department of Environmental Science and Engineering, College of Life and Environmental Science, Shanghai Normal University , Shanghai 200234, PR China.
Lihui
L
Yang
Department of Environmental Science and Engineering, College of Life and Environmental Science, Shanghai Normal University , Shanghai 200234, PR China.
Rongjie
R
Li
Department of Environmental Science and Engineering, College of Life and Environmental Science, Shanghai Normal University , Shanghai 200234, PR China.
Bin
B
Chen
Department of Environmental Science and Engineering, College of Life and Environmental Science, Shanghai Normal University , Shanghai 200234, PR China.
Lili
L
Zhang
Department of Environmental Science and Engineering, College of Life and Environmental Science, Shanghai Normal University , Shanghai 200234, PR China.
Yongming
Y
Zhang
Swette Center for Environmental Biotechnology, Biodesign Institute, Arizona State University , Tempe, AZ 85287-5701, United States.
Bruce E
BE
Rittmann
D001673:Biodegradation, Environmental; D004583:Electrons; D004785:Environmental Pollutants / Q000737:chemistry / Q000378:metabolism; D006912:Hydroxyquinolines / Q000737:chemistry / Q000378:metabolism; D010070:Oxalates / Q000737:chemistry; D010084:Oxidation-Reduction; D010782:Photolysis; D011804:Quinolines / Q000737:chemistry* / Q000378:metabolism*; D014466:Ultraviolet Rays
D004785:Environmental Pollutants; D006912:Hydroxyquinolines; D010070:Oxalates; D011804:Quinolines; C107724:2-hydroxyquinoline; C037219:quinoline