Valorizing Non-Food Carbon Sources: Discovery and Characterization of a Cyberlindnera jadinii for Single-Cell Protein Synthesis

Developing sustainable single-cell protein (SCP) from non-food feedstocks offers a promising strategy to address the escalating global demand for sustainable nutrition. However, the lack of industrially robust platforms capable of cost-efficient multi-substrate assimilation remains a key bottleneck. Here, we discover a Cyberlindnera jadinii strain, CGMCC34730, which can efficiently utilize diverse non-food carbon sources (e.g., acetate, ethanol, and xylose) for SCP production. Metabolic analysis reveals the assimilation mechanisms for these substrates, notably identifying the reductive glycine pathway as central to formic acid (FA) utilization. Scaled-up production in a 5-L bioreactor demonstrates excellent performance, with ethanol- and acetate-driven cultures reaching protein contents of 68.60 and 67.34% and volumetric productivities of 8.91 and 7.90 t m–3 y–1, respectively. The resulting SCP surpasses soybean meal and approaches the quality of fish meal, exhibiting superior essential amino acid indices alongside elevated carbohydrate and B-vitamin contents. Furthermore, we validate a circular bioeconomy model by converting electrochemically synthesized 13C-labeled acetate into SCP. Techno-economic analysis confirms that acetate-based fermentation offers optimal cost-effectiveness for industrial deployment. In summary, this GRAS-certified platform establishes a highly efficient and economically viable route for the sustainable production of high-value SCP from non-food substrates.