title: A potentiometric flow biosensor based on ammonia-oxidizing bacteria for the detection of toxicity in water.
abstract: A flow biosensor for the detection of toxicity in water using the ammonia-oxidizing bacterium (AOB) Nitrosomonas europaea as a bioreceptor and a polymeric membrane ammonium-selective electrode as a transducer is described. The system is based on the inhibition effects of toxicants on the activity of AOB, which can be evaluated by measuring the ammonium consumption rates with the ammonium-selective membrane electrode. The AOB cells are immobilized on polyethersulfone membranes packed in a holder, while the membrane electrode is placed downstream in the flow cell. Two specific inhibitors of the ammonia oxidation-allylthiourea and thioacetamide-have been tested. The IC50 values defined as the concentration of an inhibitor causing a 50% reduction in the ammonia oxidation activity have been measured as 0.17 μM and 0.46 μM for allylthiourea and thioacetamide, respectively. The proposed sensor offers advantages of simplicity, speed and high sensitivity for measuring toxicity in water.
authors.affiliation: Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS), Yantai 264003, China. qyzhang@yic.ac.cn
authors.forename: Qianyu
authors.initials: Q
authors.lastname: Zhang
authors.forename: Jiawang
authors.initials: J
authors.lastname: Ding
authors.forename: Lijuan
authors.initials: L
authors.lastname: Kou
authors.forename: Wei
authors.initials: W
authors.lastname: Qin
mesh_terms: D000641:Ammonia / Q000737:chemistry / Q000378:metabolism*; D015374:Biosensing Techniques; D018914:Cells, Immobilized / Q000737:chemistry / Q000378:metabolism; D004566:Electrodes; D006863:Hydrogen-Ion Concentration; D009606:Nitrosomonas / Q000187:drug effects / Q000378:metabolism*; D010084:Oxidation-Reduction; D011108:Polymers / Q000737:chemistry; D011199:Potentiometry; D013450:Sulfones / Q000737:chemistry; D013696:Temperature; D013853:Thioacetamide / Q000032:analysis* / Q000633:toxicity; D013890:Thiourea / Q000031:analogs & derivatives* / Q000032:analysis / Q000633:toxicity; D014867:Water / Q000737:chemistry*
chemical_list: D011108:Polymers; D013450:Sulfones; D014867:Water; D013853:Thioacetamide; C022840:polyether sulfone; C009842:allylthiourea; D000641:Ammonia; D013890:Thiourea