Harnessing Alternative Carbon Sources for Sustainable Microbial Protein Production: Integrating Bioreactors, Electrochemical Systems, and Complex Waste Streams

Microbial protein production from alternative carbon sources such as CO₂ and CH₄ has emerged as a promising and sustainable approach to reduce the environmental footprint of traditional agriculture. Recent advances in bioreactor and bioelectrochemical technologies have shown the potential for improving gas utilization efficiency and enabling carbon conversion into valuable biomass. At the same time, wastewater treatment and biogas upgrading processes represent abundant and underexploited carbon-rich resources. However, these real-world substrates are often complex and contain inhibitory or toxic compounds, including CO, H₂S, and various organic and inorganic contaminants. Such impurities can disrupt microbial activity, alter community composition, and reduce overall process effectiveness, limiting scalability and stability. Despite growing attention to these systems, the combined biological, chemical, and engineering challenges remain insufficiently explored, highlighting the need for integrative research to link fundamental mechanisms with applied system design.

This Research Topic aims to close the gap between laboratory-scale studies using purified gases and full-scale applications that rely on real waste or mixed carbon sources. It will explore how inhibitory compounds influence microbial metabolism, electron transfer, and productivity, and will emphasize strategies to enhance resilience and optimize performance. By integrating advances in bioreactor design, electrochemical systems, and microbial process engineering, the Topic seeks to identify pathways for robust and economically viable protein production processes. Special attention will be given to the development of hybrid and adaptive systems capable of operating under realistic, variable feedstock conditions and supporting a circular carbon bioeconomy.

To gather further insights into the conversion of complex carbon streams into microbial protein, we welcome contributions addressing, but not limited to, the following themes:

• Utilization of CO₂, CH₄, wastewater, and biogas as feedstocks for microbial protein production
• Effects of impurities and inhibitory compounds (e.g., CO, H₂S, ammonia, and organic pollutants) on microbial activity and system performance
• Optimization of gas–liquid transfer, electron flow, and bioelectrochemical interfaces
• Reactor, membrane, and process designs enhancing stability and scale-up potential
• Development of pretreatment methods and in situ mitigation strategies for contaminants
• Modelling, techno-economic, and life-cycle assessments of integrated microbial protein systems
• Microbial ecology, consortia design, and omics-based insights into adaptation and process robustness

Article types: Original Research, Reviews, Mini Reviews, Perspectives, Methods, and Policy Briefs.

Article types and fees

This Research Topic accepts the following article types, unless otherwise specified in the Research Topic description:

• Brief Research Report
• Data Report
• Editorial
• FAIR² Data
• Methods
• Mini Review
• Opinion
• Original Research
• Perspective
• ... View all formats

Articles that are accepted for publication by our external editors following rigorous peer review incur a publishing fee charged to Authors, institutions, or funders.

Article types

This Research Topic accepts the following article types, unless otherwise specified in the Research Topic description:

• Brief Research Report
• Data Report
• Editorial
• FAIR² Data
• Methods
• Mini Review
• Opinion
• Original Research
• Perspective
• Review
• Systematic Review
• Technology and Code

Keywords: resource recovery, bioelectrochemical systems, CO₂ utilization, Microbial protein production, CH₄ bioconversion, bioreactors, wastewater valorization, greenhouse gas recycling

Important note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.