Recycling potential of brewer's spent grains for circular biorefineries

Abstract

Brewer's spent grain (BSG) is the major by-product of the brewing industry. BSG is principally composed of carbohydrates and proteins, with substantial amount of lipids. Presently, BSG usage is restricted to low-grade applications such as ruminant feed or landfills. The high volume, nutrient-rich composition, low cost (€35/ton), abundance, and around the year availability, makes it a promising and renewable feedstock for biorefinery development. The current review begins with beer production process, where BSG is produced. Further, it appraises emerging biotechnological advancements and green processes targeting BSG valorisation ensuring maximal resource recovery. Particularly, it illustrates diverse marketable products obtained by repurposing carbohydrate and protein fraction of BSG using