Tuning of food wastes bioavailability as feedstock for bio-conversion processes by acoustic cavitation and SPC, SPS, or H2O2 as external oxidants

Abstract

The growing amount of food wastes makes them a suitable source for the generation of bioproducts through anaerobic digestion. Appropriate hydrolysis of the feedstock can enhance the efficiency of production of desired products. In this work, acoustic cavitation (AC) was employed as a pretreatment method to enhance hydrolysis stage by the modification of model (potato-based) food waste for increase in soluble chemical oxygen demand (CODs) and dissolved carbohydrate. For the first time high and low frequency AC was compared for this purpose. The application of sole AC at a frequency of 20 kHz for feedstock loading of 3 % has led to 125 % and 124 % increase in CODs and dissolved carbohydrates, respectively. The combination of AC with external oxidants hydrogen peroxide (H2O2), sodium persulfate (SPS), and sodium percarbonate (SPC) was also studied. This part of the studies revealed that SPS has superior properties for increasing CODs by 258 % and dissolved carbohydrates by 240 %. On the other hand, addition of sodium hydroxide (NaOH) as alternative reagent, leads to a 173 % increase in CODs and 155 % increase in dissolved carbohydrates. Making both ways of processing highly effective to increase the bioavailability of food wastes for further biologic processing.