Polypyrrole–ferrocene–biofilm electrode for rapid BOD biosensing and energy recovery from wastewater: Bayesian calibration for field application

Polypyrrole–ferrocene–biofilm electrode for rapid BOD biosensing and energy recovery from wastewater: Bayesian calibration for field application Full article

Journal

Bioelectrochemistry
ISSN: 1878-562X

Output data

Year: 2026, Article number : 109460, Pages count : DOI: 10.1016/j.bioelechem.2026.109460

Authors

Gurkin George ¹ , Bespalov Ivan ² , Efremov Alexey ¹ , Perchikov Roman ¹ , Medvedeva Anastasia ¹ , Usovkin Kirill ¹ , Kalish Pavel ³ , Medvedev Michael ² , Arlyapov Vyacheslav ¹

Affiliations

1	Research Center “BioChemTech”, Tula State University, Lenin Avenue 92, 300012, Tula, Russia
2	Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Pr. 47, 119991 Moscow, Russia
3	Laboratory of Composite and Carbon Materials Chemistry, Tula State University, pr. Lenina 92, 300012 Tula, Russia

Developing high-performance bioelectrodes for environmental sensing and energy recovery remains challenging. We present a ternary platform integrating polypyrrole (PPy), ferrocene, and an electroactive Rhodococcus fascian biofilm on graphite paste electrodes. Optimal PPy loading (50 μg per 0.2 cm2) was determined by impedance spectroscopy, giving a charge-transfer resistance of 28 ± 6 Ω·cm2 for the PPy-ferrocene-biofilm system – more than 1200 times lower than that of the PPy–biofilm electrode. The bioelectrode served both as a BOD biosensor and as an anode in a 3D-printed dual-chamber microbial fuel cell (MFC). The biosensor exhibited a wide linear range of 4–600mg O2/dm3, a ~5min response time, and 6% RSD. For the first time in a whole-cell BOD sensor, Bayesian calibration reduced the required standards from 15 to 7 while preserving accuracy and providing uncertainty quantification for the Hill equation parameters. Validation against the standard BOD5 method on real surface waters yielded R2=0.9828. In the MFC, the ternary anode delivered a power density of 2.0mW·m-2 and removed 89% of COD and 92% of BOD from domestic wastewater. These results confirm the synergistic effect of the conductive polymer, mediator, and biofilm, offering a versatile platform for rapid water-quality monitoring and wastewater treatment with concomitant electricity generation.

Gurkin G. , Bespalov I. , Efremov A. , Perchikov R. , Medvedeva A. , Usovkin K. , Kalish P. , Medvedev M. , Arlyapov V.
Polypyrrole–ferrocene–biofilm electrode for rapid BOD biosensing and energy recovery from wastewater: Bayesian calibration for field application
Bioelectrochemistry. 2026. 109460 . DOI: 10.1016/j.bioelechem.2026.109460 OpenAlex

Submitted:	Jul 7, 2026
Published print:	Sep 17, 2026

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