Optimization of Volatile Fatty Acids Production for Phas Synthesis from Food Wastes

Abstract

Food wastage is an ethical and environmental wrong practice. Considering a circular economy optic, food waste is a carbon rich substrate, suited for anaerobic fermentation to produce not only biogas, but also high-value chemical compounds, such as Volatile Fatty Acids (VFAs), that can be recovered in order to synthetize polyhydroxyalkanoates (PHAs). This work represented a step in a larger biorefinery process for food waste treatment, having the aim to explore the production and the profile of VFAs from of three different food waste substrates: Stillage, Condensate and Spent Coffee Ground. The substrates were considered at three different pH conditions (uncontrolled, 7, 12), anaerobically digested in batch reactors for VFAs accumulation. The best VFAs yields belonged to pH 7 tests for all the substrates. The best one on terms of VFAs productivity was Food Stillage with 36.17 gCOD/L of VFAs concentration, corresponding to a VFAs yield of 49.48 % w/w.