Hydrogen (H2) is increasingly recognized as a promising solution for a sustainable energy future. The production of biohydrogen using microbes, combined with renewable, low-cost, and abundant resources, presents an economically attractive and environmentally friendly approach. One-carbon compounds, such as carbon monoxide (CO) and formate, are considered promising feedstocks. These compounds can be derived from CO-rich industrial by-products or waste gases or produced through the electrochemical reduction of greenhouse gas carbon dioxide, providing a cost-effective and practical solution. Researchers have identified a variety of microbes capable of utilizing CO or formate, and significant efforts are underway to enhance H2 production through strain improvement and bioprocess optimization. Thermococcus onnurineus NA1, isolated from a deep-sea hydrothermal vent, has been engineered to become an efficient H2 producer. Enhancements in its performance have involved addressing CO toxicity and improving enzymatic substrate conversion through promoter engineering and adaptive evolution techniques. In this context, various strategies that have been implemented are outlined, along with explanations of the underlying molecular mechanisms based on genomic and transcriptomic analyses. The developed technology was successfully scaled up to large bioreactors, demonstrating the feasibility of using industrial by-product gases as feedstock for biohydrogen production.