School of Biology, Georgia Institute of Technology , Atlanta, Georgia 30332, United States.
Environ Sci Technol. 2014 Nov 4;48(21):12858-67. doi: 10.1021/es503454a. Epub 2014 Oct 27.
The carcinogenic cyclic ether compound 1,4-dioxane is employed as a stabilizer of chlorinated industrial solvents and is a widespread environmental contaminant in surface water and groundwater. In the present study, a microbially driven Fenton reaction was designed to autocatalytically generate hydroxyl (HO•) radicals that degrade 1,4-dioxane. In comparison to conventional (purely abiotic) Fenton reactions, the microbially driven Fenton reaction operated at circumneutral pH and did not the require addition of exogenous H2O2 or UV irradiation to regenerate Fe(II) as Fenton reagents. The 1,4-dioxane degradation process was driven by pure cultures of the Fe(III)-reducing facultative anaerobe Shewanella oneidensis manipulated under controlled laboratory conditions. S. oneidensis batch cultures were provided with lactate, Fe(III), and 1,4-dioxane and were exposed to alternating aerobic and anaerobic conditions. The microbially driven Fenton reaction completely degraded 1,4-dioxane (10 mM initial concentration) in 53 h with an optimal aerobic-anaerobic cycling period of 3 h. Acetate and oxalate were detected as transient intermediates during the microbially driven Fenton degradation of 1,4-dioxane, an indication that conventional and microbially driven Fenton degradation processes follow similar reaction pathways. The microbially driven Fenton reaction provides the foundation for development of alternative in situ remediation technologies to degrade environmental contaminants susceptible to attack by HO• radicals generated by the Fenton reaction.
致癌环状醚化合物 1,4-二恶烷被用作氯化工业溶剂的稳定剂，是地表水和地下水中广泛存在的环境污染物。在本研究中，设计了一种微生物驱动的芬顿反应，以自动催化生成羟基 (HO•) 自由基，从而降解 1,4-二恶烷。与传统的（纯非生物）芬顿反应相比，微生物驱动的芬顿反应在近中性 pH 下运行，并且不需要添加外源 H2O2 或紫外线辐照来再生芬顿试剂中的 Fe(II)。1,4-二恶烷的降解过程由在受控实验室条件下操纵的三价铁还原兼性厌氧菌希瓦氏菌的纯培养物驱动。将希瓦氏菌分批培养物提供给乳酸盐、Fe(III)和 1,4-二恶烷，并使其暴露于交替的需氧和厌氧条件下。微生物驱动的芬顿反应在 53 小时内完全降解了 1,4-二恶烷（初始浓度为 10 mM），最佳的需氧-厌氧循环周期为 3 小时。在 1,4-二恶烷的微生物驱动的芬顿降解过程中，检测到了乙酸盐和草酸盐作为瞬态中间体，表明传统的和微生物驱动的芬顿降解过程遵循相似的反应途径。微生物驱动的芬顿反应为开发替代的原位修复技术提供了基础，这些技术可以降解易受芬顿反应生成的 HO•自由基攻击的环境污染物。
