Polyethylene glycol as a robust, biocompatible encapsulant for two-stage treatment of food and beverage wastewater

Abstract

This research investigates encapsulation of microorganisms for two-stage anaerobic treatment of industrial food and beverage wastewater. Encapsulants were tested in batch reactors to determine the potential for biological inhibition during encapsulation. Flow through reactors were to test the leakage of microorganisms from the encapsulants over time. Five different reactor designs were explored to assess the effects of reactor conditions on encapsulant longevity and activity. It was found that polyethylene glycol (PEG) beads encapsulating biomass grown in suspension did not change in shape, activity, or protein concentration over one month in flow-through reactors. In reactors mixed by stir bars, PEG beads encapsulating suspended biomass lasted 6-10 months. PEG beads encapsulating PAC-supported biofilms improved methane production approximately 27 times compared to PEG beads encapsulating suspended biomass. This study provides information on encapsulant performance that will be used to select encapsulants for a future pilot demonstration of the pretreatment system at a brewery.