Food production from air: gas precision fermentation with hydrogen-oxidising bacteria.

The breach of six planetary boundaries highlights the need for sustainable food production. Aerobic hydrogen-oxidising bacteria (HOBs) convert atmospheric CO2 and green hydrogen (H2) into biomass via gas fermentation, a process already used for food-grade single-cell protein production. This approach enables a supply chain independent of agriculture, requiring minimal land and water, with potential for carbon-neutral production and carbon capture. To expand beyond single-cell protein, HOBs must be engineered into cell factories for precision fermentation. Advances in synthetic biology, metabolic engineering, computational modelling, and bioreactor design have accelerated the development of scalable bioprocesses providing a blueprint for gas-based fermentation. We present a path forward using secreted recombinant milk protein as a case study, highlighting key challenges and opportunities.