Cui Mingchao, Zhang Wenbing, Fang Jun, Liang Qianqiong, Liu Dongxuan
School of Environmental Science and Engineering, Guangzhou University, No. 230 WaiHuanXi Road, Guangzhou Higher Education Mega Center, Guangzhou, 510006, China.
Guangdong Provincial Key Laboratory of Radioactive Contamination Control and Resources, Guangzhou University, Guangzhou, 510006, China.
Appl Microbiol Biotechnol. 2017 Aug;101(16):6563-6572. doi: 10.1007/s00253-017-8379-1. Epub 2017 Jun 16.
Compound-specific isotope analysis has been used extensively to investigate the biodegradation of various organic pollutants. To date, little isotope fractionation information is available for the biodegradation of quinolinic compounds. In this study, we report on the carbon and hydrogen isotope fractionation during quinoline and 3-methylquinoline aerobic microbial degradation by a Comamonas sp. strain Q10. Degradation of quinoline and 3-methylquinoline was accompanied by isotope fractionation. Large hydrogen and small carbon isotope fractionation was observed for quinoline while minor carbon and hydrogen isotope fractionation effects occurred for 3-methylquinoline. Bulk carbon and hydrogen enrichment factors (ε ) for quinoline biodegradation were -1.2 ± 0.1 and -38 ± 1‰, respectively, while -0.7 ± 0.1 and -5 ± 1‰ for 3-methylquinoline, respectively. This reveals a potential advantage for employing quinoline as the model compound and hydrogen isotope analysis for assessing aerobic biodegradation of quinolinic compounds. The apparent kinetic isotope effects (AKIE) values of carbon were 1.008 ± 0.0005 for quinoline and 1.0048 ± 0.0005 for 3-methylquinoline while AKIE values of hydrogen of 1.264 ± 0.011 for quinoline and 1.0356 ± 0.0103 for 3-methylquinoline were obtained. The combined evaluation of carbon and hydrogen isotope fractionation yields Λ values (Λ = ΔδH/ΔδC ≈ εH/εC) of 29 ± 2 for quinoline and 8 ± 2 for 3-methylquinoline. The results indicate that the substrate specificity may have a significant influence on the isotope fractionation for the biodegradation of quinolinic compounds. The substrate-specific isotope enrichment factors would be important for assessing the behavior and fate of quinolinic compounds in the environment.
化合物特异性同位素分析已被广泛用于研究各种有机污染物的生物降解。迄今为止，关于喹啉类化合物生物降解的同位素分馏信息很少。在本研究中，我们报告了丛毛单胞菌属菌株Q10对喹啉和3-甲基喹啉进行好氧微生物降解过程中的碳和氢同位素分馏情况。喹啉和3-甲基喹啉的降解伴随着同位素分馏。喹啉观察到较大的氢同位素分馏和较小的碳同位素分馏，而3-甲基喹啉则出现较小的碳和氢同位素分馏效应。喹啉生物降解的总碳和氢富集因子（ε）分别为-1.2±0.1和-38±1‰，而3-甲基喹啉分别为-0.7±0.1和-5±1‰。这揭示了使用喹啉作为模型化合物和氢同位素分析来评估喹啉类化合物好氧生物降解的潜在优势。喹啉的碳表观动力学同位素效应（AKIE）值为1.008±0.0005，3-甲基喹啉为1.0048±0.0005，而喹啉的氢AKIE值为1.264±0.011，3-甲基喹啉为1.0356±0.0103。碳和氢同位素分馏的综合评估得出喹啉的Λ值（Λ=ΔδH/ΔδC≈εH/εC）为29±2，3-甲基喹啉为8±2。结果表明，底物特异性可能对喹啉类化合物生物降解的同位素分馏有显著影响。底物特异性同位素富集因子对于评估喹啉类化合物在环境中的行为和归宿将是重要的。
