How UV photolysis accelerates the biodegradation and mineralization of sulfadiazine (SD)

• Published in: Biodegradation (Dordrecht) 2014-11, Vol.25 (6), p.911-921
• Main Authors: Pan, Shihui, Yan, Ning, Liu, Xinyue, Wang, Wenbing, Zhang, Yongming, Liu, Rui, Rittmann, Bruce E.
• Format: Article
• Language: English
• Subjects: ABS; Antibiotics; Aquatic Pollution; Biodegradation; Biodegradation of pollutants; Biodegradation, Environmental; Biological and medical sciences; Biomedical and Life Sciences; Biotechnology; Environment and pollution; Equivalence; Evaluation; Fundamental and applied biological sciences. Psychology; Geochemistry; Industrial applications and implications. Economical aspects; Joining; Kinetics; Life Sciences; Microbiology; Mineralization; Original Paper; Oxygenation; Pathways; Photobiology; Photolysis; Purification; Reactors; Sewage; Soil Science & Conservation; Sulfadiazine; Sulfadiazine - chemistry; Sulfadiazine - metabolism; Terrestrial Pollution; Waste Management/Waste Technology; Waste Water Technology; Wastewater; Wastewater treatment; Water Management; Water Pollution Control; Water treatment
• ISSN: 0923-9820; 1572-9729
• DOI: 10.1007/s10532-014-9711-4

Sulfadiazine (SD), one of broad-spectrum antibiotics, exhibits limited biodegradation in wastewater treatment due to its chemical structure, which requires initial mono-oxygenation reactions to initiate its biodegradation. Intimately coupling UV photolysis with biodegradation, realized with the internal loop photobiodegradation reactor, accelerated SD biodegradation and mineralization by 35 and 71 %, respectively. The main organic products from photolysis were 2-aminopyrimidine (2-AP), p -aminobenzenesulfonic acid (ABS), and aniline (An), and an SD-photolysis pathway could be identified using C, N, and S balances. Adding An or ABS (but not 2-AP) into the SD solution during biodegradation experiments (no UV photolysis) gave SD removal and mineralization rates similar to intimately coupled photolysis and biodegradation. An SD biodegradation pathway, based on a diverse set of the experimental results, explains how the mineralization of ABS and An (but not 2-AP) provided internal electron carriers that accelerated the initial mono-oxygenation reactions of SD biodegradation. Thus, multiple lines of evidence support that the mechanism by which intimately coupled photolysis and biodegradation accelerated SD removal and mineralization was through producing co-substrates whose oxidation produced electron equivalents that stimulated the initial mono-oxygenation reactions for SD biodegradation.