Recent developments and future prospects in biohythane and biomethane production from food waste

Food waste (FW) represents a major global challenge because of its significant economic, environmental, and social effects. This review critically evaluates recent advances in acidogenic processes, including dark fermentation (DF), anaerobic digestion (AD), and hybrid DF-AD systems, for converting FW into renewable biofuels such as hydrogen, methane, and biohythane. These technological advances are largely influenced by the need to reduce the number of landfills and the level of greenhouse gas emissions by transforming the high organic composition of FW into sustainable energy sources. This review recognizes single-stage AD as an economical and sufficiently proven approach for methane production and indicates that it underutilizes the potential of hydrogen as an energy source. DF technology is designed to separate hydrogen and allow the energy potential of volatile fatty acids and other byproducts. Integrated DF-AD systems can solve the current limitations by separating hydrogenogenic and methanogenic processes, which enhances the energy recovery and stability of the processes. Despite their potential benefits, multi-stage systems are more capital-intensive and demand advanced process monitoring, which can reduce their overall feasibility. The physicochemical characteristics of FW, such as pH, temperature, and organic loading, were examined, as well as the imperative role of monitoring tools. Controlling the nutrient-rich content of digestate is critical for achieving circular economy goals. Post-treatment, such as hydrothermal carbonization and pyrolysis, can be used to increase the value of digestate, whereas nutrient recovery can minimize the risk of contamination. Finally, techno-economic studies highlight the importance of supportive policies, stable FW collection, and stakeholder involvement in large-scale adoption. Future research must require the optimization of perfect microbial communities as well as real-time management process techniques as it seeks to explore advanced reactor systems that would place FW-derived biofuels as vital components to bring about low-carbon economic growth that is sustainable.