Abstract：
Chlorinated volatile organic compounds (Cl-VOCs) have dramatically biotoxicity and environmental persistence due to the presence of chlorine atoms, seriously jeopardizing ecological security and human health. Dichloromethane (DCM) as a model pollutant, is widely applied in solvents, extractants and cleaning agents in the pharmaceutical, chemical and food industries. In this study, highly biocompatible and conductive carbon cloth-titanium nitride-polyaniline (CC-TiN-PANI) bioelectrodes were obtained for DCM degradation in microbial electrolysis cell (MEC). The good adhesion of TiN and PANI on the electrode surface was demonstrated. The degradation kinetics were fitted by the Haldane model, compared to the CC bioelectrode (0.8 h-1), the proportion of maximum degradation rates to half-saturation concentration (Vmax/Km) of CC-TiN (1.4 h-1) and CC-TiN-PANI (2.2 h-1) bioelectrodes were enhanced by 1.8 and 2.8 times, respectively. Microbial community structure analysis illuminated that the dominant genera on the biofilm were Alicycliphilus and Hyphomicrobium, and the abundance was enhanced significantly with the modification of TiN and PANI. The dechlorination of DCM to formaldehyde could be catalyzed by DCM dehalogenase (DcmA) or by haloalkane dehalogenase (DhlA). And further oxidized to formate: 1) direct catalyzed by formaldehyde dehydrogenase (FdhA); 2) conjugated with glutathione by S-(hydroxymethyl)-glutathione synthase (Gfa), S-(hydroxymethyl)-glutathione dehydrogenase (FrmA) and S-formyl-glutathione hydrolase (FrmB); 3) conjugation with tetrahydrofolate (H4F) and/or tetrahydromethanopterin.
摘要：
氯化挥发性有机化合物（Cl-VOCs）具有显著的生物毒性和环境持久性由于氯原子的存在，严重危害生态安全和人类健康。二氯甲烷(DCM)作为模型污染物，广泛应用于溶剂中，制药中的萃取剂和清洁剂，化工和食品工业。在这项研究中,在微生物电解槽（MEC）中获得了高度生物相容性和导电性的碳-氮化钛-聚苯胺（CC-TiN-PANI）生物电极，用于DCM降解。证实了TiN和PANI在电极表面上的良好粘附。用Haldane模型拟合降解动力学,与CC生物电极(0.8h-1)相比，CC-TiN（1.4h-1）和CC-TiN-PANI（2.2h-1）生物电极的最大降解速率与半饱和浓度（Vmax/Km）的比例分别提高了1.8和2.8倍，分别。微生物群落结构分析表明，生物膜上的优势属是脂类和赤霉属，随着TiN和PANI的改性，丰度显著增强。DCM脱氯为甲醛可由DCM脱卤酶(DcmA)或卤代烷脱卤酶(DhlA)催化。并进一步氧化为甲酸盐：1）甲醛脱氢酶（FdhA）直接催化；2）通过S-（羟甲基）-谷胱甘肽合酶（Gfa）与谷胱甘肽偶联，S-（羟甲基）-谷胱甘肽脱氢酶（FrmA）和S-甲酰-谷胱甘肽水解酶（FrmB）；3）与四氢叶酸（H4F）和/或四氢甲烷蝶呤偶联。
