Industrial-scale biorefinery for n-caproate production from food waste†

Food waste contributes nearly 10% of global carbon emissions, with over one billion tonnes produced annually. Carbon chain elongation (CCE) technology converts bio-waste into biochemicals via microbial catalysis. Here, we present an industrial-scale biorefinery plant to produce n-caproate from food waste. This plant can stably produce green n-caproate from food waste at atmospheric temperatures without added chemicals and heat energy. Gibbs free energy analysis demonstrated the underlying biochemical reactions of the CCE system, and techno-economic evaluation showed reduced operational cost and greenhouse gas emission due to avoidable chemicals and heat energy. Since the residual broth from the extraction of n-caproate can be employed as an alternative carbon source for nitrogen removal in wastewater treatment, a theoretical model was proposed to estimate the concentrations of residual dissolved organic nitrogen in the effluent. This industrial-scale biorefinery for n-caproate would offer a closed-loop system for the sustainable cascade management of food waste.