title: Assessing the effect of oxygen and microbial inhibitors to optimize ferricyanide-mediated BOD assay.
abstract: Methods for short-term BOD analysis (BOD(st)) based on ferricyanide mediator reduction have succeeded in overcoming some problems associated with the standard BOD test analysis (BOD(5)) such as long-term incubations (5 days), the need to dilute samples and low reproducibility. Here we present a bioassay where a Klebsiella pneumoniae environmental strain successfully reduces ferricyanide without de-aeration of the samples with linear BOD(5) ranges between 30 and 500 mg L(-1) or 30 and 200 mg L(-1), using glucose-glutamic acid solution (GGA) or OECD standards respectively. We further propose a new assay termination solution that allows higher reproducibility and standardization of the cell-based assay, employing formaldehyde (22.7 g L(-1)) or other compounds in order to stop ferricyanide reduction without affecting the amperometric detection and therefore replace the centrifugation step normally used to stop microbial-driven reactions in ferricyanide-mediated bioassays. These improvements led to an accurate determination of real municipal wastewater samples.
authors.affiliation: Biosensors and Bioanalysis Group, Department of Biochemistry, Faculty of Sciences, Universidad de Buenos Aires, Ciudad Universitaria, Ciudad Autónoma de Buenos Aires C1428EGA, Argentina. celinatt@yahoo.com.ar
authors.forename: M Celina
authors.initials: MC
authors.lastname: Bonetto
authors.forename: Natalia J
authors.initials: NJ
authors.lastname: Sacco
authors.forename: Astrid Hilding
authors.initials: AH
authors.lastname: Ohlsson
authors.forename: Eduardo
authors.initials: E
authors.lastname: Cortón
mesh_terms: D001681:Biological Assay / Q000379:methods; D005292:Ferricyanides / Q000378:metabolism*; D007711:Klebsiella pneumoniae / Q000378:metabolism*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000032:analysis* / Q000378:metabolism; D012722:Sewage / Q000032:analysis / Q000382:microbiology; D014865:Waste Disposal, Fluid
chemical_list: D005292:Ferricyanides; D012722:Sewage; D010100:Oxygen