Department of Environmental Science and Engineering, College of Life and Environmental Science, Shanghai Normal University , Shanghai, 200234, People's Republic of China.
Environ Sci Technol. 2014;48(1):649-55. doi: 10.1021/es404399t. Epub 2013 Dec 23.
Pyridine, a nitrogen-containing heterocyclic compound, is slowly biodegradable, and coupling biodegradation with UV photolysis is a potential means to accelerate its biotransformation and mineralization. The initial steps of pyridine biodegradation involve mono-oxygenation reactions that have molecular oxygen and an intracellular electron carrier as cosubstrates. We employed an internal circulation baffled biofilm reactor for pyridine biodegradation following three protocols: direct biodegradation (B), biodegradation after photolysis (P+B), and biodegradation with succinic acid added (B+S). Succinic acid was the main UV-photolysis product from pyridine, and its catabolic oxidation generates internal electron carriers that may accelerate the initial steps of pyridine biodegradation. Compared with direct biodegradation of pyridine (B), the removal rate for the same concentration of photolyzed pyridine (P+B) was higher by 15 to 43%, depending on the initial pyridine concentrations (increasing through the range of 130 to 310 mg/L). Adding succinic acid alone (B+S) gave results similar to P+B, which supports that succinic acid was the main agent for accelerating the pyridine biodegradation rate. In addition, protocols P+B and B+S were similar in terms of increasing pyridine mineralization over 10 h: 84% and 87%, respectively, which were higher than with protocol B (72%). The positive impact of succinic acid-whether added directly or produced via UV photolysis-confirms that its catabolism, which produced intracellular electron carriers, accelerated the initial steps of pyridine biotransformation.
吡啶是一种含氮杂环化合物，其生物降解速度缓慢，将生物降解与紫外光解偶联是加速其生物转化和矿化的潜在手段。吡啶生物降解的初始步骤涉及单加氧反应，需要分子氧和细胞内电子载体作为共底物。我们采用内部循环挡板生物膜反应器进行了三种方案下的吡啶生物降解实验：直接生物降解（B）、光解后生物降解（P+B）和添加琥珀酸的生物降解（B+S）。琥珀酸是吡啶光解的主要产物，其代谢氧化会产生内部电子载体，可能会加速吡啶生物降解的初始步骤。与直接生物降解吡啶（B）相比，相同浓度光解吡啶（P+B）的去除率提高了 15%至 43%，具体取决于初始吡啶浓度（从 130 至 310mg/L 范围内增加）。单独添加琥珀酸（B+S）的效果与 P+B 相似，这表明琥珀酸是加速吡啶生物降解速率的主要因素。此外，在 10 小时内，P+B 和 B+S 方案都能提高吡啶矿化率，分别为 84%和 87%，高于 B 方案（72%）。琥珀酸的积极影响——无论是直接添加还是通过紫外光解产生——都证实了其代谢产物，即产生细胞内电子载体的琥珀酸，加速了吡啶生物转化的初始步骤。
