Use of one- and two-mediator systems for developing a BOD biosensor based on the yeast Debaryomyces hansenii

Publication date: Available online 26 December 2016 Source:Enzyme and Microbial Technology Author(s): A.S. Zaitseva, V.A. Arlyapov, N.Yu. Yudina, S.V. Alferov, A.N. Reshetilov We investigated the use of one- and two-mediator systems in amperometric BOD biosensors (BOD, biochemical oxygen demand) based on the yeast Debaryomyces hansenii. Screening of nine mediators potentially capable of electron transfer − ferrocene, 1,1′-dimethylferrocene, ferrocenecarboxaldehyde, ferroceneacetonitrile, neutral red, 2,6-dichlorophenolindophenol, thionine, methylene blue and potassium ferricyanide − showed only ferrocene and neutral red to be efficient electron carriers for the eukaryotes studied. Two-mediator systems based on combinations of the investigated compounds were used to increase the efficiency of electron transfer. The developed two-mediator biosensors exceeded their one-mediator analogs by their characteristics. The most preferable two-mediator system for developing a BOD biosensor was a ferrocene–methylene blue combination that ensured a satisfactory long-time stability (43 days), selectivity, sensitivity (the lower limit of the determined BOD5 concentrations, 2.5mg О2/dm3) and speed (assay time for one sample, not greater than 10min) of BOD determination. Analysis of water samples showed that the use of a ferrocene–methylene blue two-mediator system and the yeast D. hansenii enabled registration of data that highly correlated with the results of the standard m...

Source: Enzyme and Microbial Technology - December 26, 2016 Category: Biotechnology Source Type: research