Biofuel Cell Based on Bacteria of the Genus Gluconobacter as a Sensor for Express Analysis of Biochemical Oxygen Demand

The anode of a microbial fuel cell was used to determine the index of biochemical oxygen demand. The fuel cell was developed with an activated graphite electrode modified with polyvinyl alcohol containing N-vinylpyrrolidone. The combination of polyvinyl alcohol with N-vinylpyrrolidone was used to immobilize Gluconobacter oxydans bacteria. The application of this matrix made it possible to obtain a microbial fuel cell possessing a high sensitivity and a minimal time for a single measurement of the BOD5 index, which were 8.3 mV dm3/mg O2 and 30 min, respectively. The lower limit of the determined values of biochemical oxygen demand was 0.34 mg O2/dm3. The determination of the wastewater BOD5 indicated that these results agreed with the data of the standard method (the correlation coefficient was 0.99). The studied biosensor model exceeded the described analogs in such characteristics as the lower limit of detection and the minimal time for a single measurement.