Chemical transformation of food and beverage waste-derived fructose to hydroxymethylfurfural as a value-added product

A novel alternative bioconversion and chemical transformation method for valorisation of food and beverage (F&B) waste to hydroxymethylfurfural (HMF) is reported. Solid-to-liquid ratio of 70% was applied to hydrolyse F&B waste by glucoamylase and sucrase to yield a hydrolysate consisted of glucose and fructose. After impurity removal using chromatography columns, the purified hydrolysate was processed by glucose isomerase to produce syrup with a fructose-to-glucose ratio of 1:1. After removal of the residual impurities using ion exchange columns, Simulated Moving Bed system was applied to separate sugars in fructose-glucose syrup. The resultant high-fructose syrup contained 89.0 g/L fructose, which was demonstrated as an ideal feedstock for the synthesis of HMF. By employing a commercial solid acid catalyst (Amberlyst 36), 71 mol% HMF with a high selectivity of 77 mol% was generated from this high-fructose syrup under mild microwave heating at 140 °C within 40 min.The increase in catalyst loading accelerated both HMF formation and HMF-consuming side reactions, under-scoring the trade-off between the conversion rate and product selectivity. The solid catalyst can be recovered and successfully reused for four runs with the HMF yield at 70 mol%. An overall conversion yield of 30 g HMF/kg F&B waste was achieved. This work emphasises a novel integration of chemical and biological technologies for selective production of HMF from mixed F&B waste.