Microbiological aspects of microbial electrolysis cells: Isolation, screening, and electron transfer mechanisms

Twisampati Das; Bhawna Kandwal; Riddhi Chakraborty; Harsh Jadhav; Ayesha Mulla; Rajesh Kanawade; Suhas S. Shetye; Ibrahim M. Banat; Surekha K. Satpute; Twisampati Das; Bhawna Kandwal; Riddhi Chakraborty; Harsh Jadhav; Ayesha Mulla; Rajesh Kanawade; Suhas S. Shetye; Ibrahim M. Banat; Surekha K. Satpute

doi:10.3934/microbiol.2026019

AIMS Microbiology

2026, Volume 12, Issue 3: 439-471. doi: 10.3934/microbiol.2026019

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Review article

Microbiological aspects of microbial electrolysis cells: Isolation, screening, and electron transfer mechanisms

1.
Department of Microbiology, Savitribai Phule Pune University, Pune 411007, Maharashtra, India
2.
CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, Maharashtra, India
3.
CSIR-National Institute of Oceanography, Dona Paula, 403004, Goa, India
4.
School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, BT52 1SA, UK

Received: 17 March 2026 Revised: 25 June 2026 Accepted: 30 June 2026 Published: 07 July 2026

Biohydrogen is a leading candidate in the global shift toward renewable energy, offering a sustainable solution to reduce reliance on fossil fuels. This review underscores the use of microbial electrolysis cells (MECs) as a viable strategy to address increasing energy demands. In MECs, extracellular electron transfer (EET) is a vital mechanism that enables microorganisms to channel electrons (e⁻) from organic donors to external acceptors. Exo-electrogenic bacteria, viz., Geobacter, Shewanella, Pseudomonas, Nitrospira, and Desulfovibrio, are frequently reported for their ability to utilize Iron: Fe (III) and Manganese: Mn (III/IV) as electron acceptors, which can be replaced with electrodes to drive proton reduction and hydrogen (H₂) generation. The use of renewable substrates in fermentation processes further strengthens the commercial feasibility of biohydrogen production, while the molecular traits of microbes provide insights into optimizing H₂ production. Despite encouraging laboratory-scale demonstrations, challenges persist due to variability in recovery methods and the limited microbial diversity explored. Expanding the repertoire of exo-electrogens and refining MEC configurations are critical to achieving higher yields. Overall, biohydrogen stands out as a clean, eco-friendly energy resource, with microbial electrolysis offering a sustainable energy technology.
- biohydrogen,
- exo-electrogen,
- biofilms,
- microbes,
- microbial electrolysis cells,
- substrates
Citation: Twisampati Das, Bhawna Kandwal, Riddhi Chakraborty, Harsh Jadhav, Ayesha Mulla, Rajesh Kanawade, Suhas S. Shetye, Ibrahim M. Banat, Surekha K. Satpute. Microbiological aspects of microbial electrolysis cells: Isolation, screening, and electron transfer mechanisms[J]. AIMS Microbiology, 2026, 12(3): 439-471. doi: 10.3934/microbiol.2026019

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Abstract

Biohydrogen is a leading candidate in the global shift toward renewable energy, offering a sustainable solution to reduce reliance on fossil fuels. This review underscores the use of microbial electrolysis cells (MECs) as a viable strategy to address increasing energy demands. In MECs, extracellular electron transfer (EET) is a vital mechanism that enables microorganisms to channel electrons (e⁻) from organic donors to external acceptors. Exo-electrogenic bacteria, viz., Geobacter, Shewanella, Pseudomonas, Nitrospira, and Desulfovibrio, are frequently reported for their ability to utilize Iron: Fe (III) and Manganese: Mn (III/IV) as electron acceptors, which can be replaced with electrodes to drive proton reduction and hydrogen (H₂) generation. The use of renewable substrates in fermentation processes further strengthens the commercial feasibility of biohydrogen production, while the molecular traits of microbes provide insights into optimizing H₂ production. Despite encouraging laboratory-scale demonstrations, challenges persist due to variability in recovery methods and the limited microbial diversity explored. Expanding the repertoire of exo-electrogens and refining MEC configurations are critical to achieving higher yields. Overall, biohydrogen stands out as a clean, eco-friendly energy resource, with microbial electrolysis offering a sustainable energy technology.

Acknowledgments

We would like to thank Savitribai Phule Pune University, Pune 411007, Maharashtra, India for supporting this project. Dr. Surekha K. Satpute expresses gratitude towards Department of Science and Technology-Fund for Improvement of S and T Infrastructure (Ref: DST-FIST 2021/LS-1/851), Government of India, Anusandhan National Research Foundation (ANRF), New Delhi (Ref: ANRF/PAIR/2025/000015/PAIR-B), and Rashtriya Uchchatar Shiksha Abhiyan (Ref: RUSA-CBS-TH-3.2) for financial support.

Conflict of interest

The authors declare no conflict of interest.

Author contributions

TD, BK, RC, HJ, and AM, were involved in data collection and writing the initial draft of the manuscript. TD, RC, HJ and AM were involved in scientific illustrations. RK, SSS, IMB, and SKS contributed to editing the manuscript, conceptualization, and finalizing the review article. All authors have approved the final draft of the manuscript and agreed to submit the final version of the same.

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