Power-to-Protein: Electro-cultivation of microbial proteins from recycled nitrogen and carbon dioxide

This review explores microbial proteins (MP) as a sustainable alternative to traditional protein sources, emphasizing the innovative approach of electro-cultivation, which integrates biological and electrochemical systems. MP production offers substantial environmental advantages, including efficient carbon dioxide fixation, nitrogen recycling, and production resilience to climate variability, achieving protein contents of over 80 %. The review examines key metabolic pathways for MP synthesis, with a particular focus on the potential of hydrogen-oxidizing bacteria for converting renewable energy and waste substrates like carbon dioxide and ammonium into high-value protein. Inputs such as renewable electricity, nutrient sources, and bio-waste utilization are analyzed alongside the challenges of scaling water splitting technologies to support microbial growth. Furthermore, the paper reviews downstream processing techniques for producing high-quality MP, evaluates the economic feasibility of MP production (costing approximately 1€ per kg of dry weight), and highlights its significant environmental advantages over conventional agriculture. Regulatory aspects are discussed in the context of evolving frameworks to support the commercialization of MP. In conclusion, this review identifies critical research gaps, including strategies to improve microbiome stability, efficient gas utilization, product acceptance, and shelf-life studies, offering a roadmap for advancing MP electro-cultivation into a scalable and globally relevant solution for sustainable food systems.