Sulfur-Oxidizing Bacteria: Potential Contributors to High-Quality Protein Production Coupled with CO2 Utilization.

The global protein gap is widening due to population growth, and traditional sources, such as soybeans, are insufficient. Single-cell proteins provide another option, but heterotrophic bacteria emit CO2 during production, and the production by alga protein is restricted by light supply. Sulfur-oxidizing bacteria (SOB) can use reduced sulfur and CO2 to synthesize bacterial protein with a high methionine content, which can be used as a supplement to animal feed. So SOB are potential protein producers coupled with CO2 utilization. However, their efficiency is still low compared to heterotrophic bacteria and alga, which should be further enhanced through energy optimization and metabolic regulation.