The Potential of Brewer’s Spent Grain in the Circular Bioeconomy: State of the Art and Future Perspectives

Abstract

Brewer’s spent grain (BSG) accounts for approximately 85% of the total mass of solid by-products in the brewing industry and represents an important secondary raw material of future biorefineries. Currently, the main application of BSG is limited to the feed and food industry. There is a strong need to develop sustainable pretreatment and fractionation processes to obtain BSG hydrolysates that enable efficient biotransformation into biofuels, biomaterials, or biochemicals. This paper aims to provide a comprehensive insight into the availability of BSG, chemical properties, and current and potential applications juxtaposed with the existing and emerging markets of the pyramid of bio-based products in the context of sustainable and circular bioeconomy. An economic evaluation of BSG for the production of highly valuable products is presented in the context of sustainable and circular bioeconomy targeting the market of Central and Eastern European countries (BIOEAST region).

Anaerobic digestion of brewer’s spent grain with biochars—biomethane production and digestate quality effects

“…Substrates used in this research had properties similar to those that can be found in the literature (Mainardis et al, 2019;Zeko-Pivač et al, 2022). The pyrolysis temperature is one of the most important parameters (excluding feedstock type) affecting the quality of the produced BC (Zhao et al, 2021).…”

Spent Grain: A Functional Ingredient for Food Applications

“…Spent grain is a low cost by-product that is available throughout the year, is nutritionally valuable, rich in fiber, proteins and minerals and can be reused in both food and non-food sectors, including animal feed, compost preparations, biogas production, cultivation of microorganisms and production of biomaterials, biochemicals and bricks [ 33 , 37 , 38 ]. Spent grain extract is an approved ingredient in food supplements [ 39 ].…”

“…Phenolics in spent grains are associated with the prevention of chronic cardiovascular and neurogenerative diseases, certain cancers and diabetes. The high fiber content helps in the elimination of cholesterol and fats and improves symptoms of ulcerative colitis [ 31 , 33 , 34 , 35 , 36 ]. Reusing spent grain as a value-added food source for human consumption is appealing because it increases the protein, fiber, vitamin and mineral contents while decreasing the starch and caloric content in grain-based products [ 40 ].…”

“…Spent grain is a by-product with high nutritional value, thus it is important to identify innovative solutions for returning waste and by-products into the production cycle to obtain innovative quality products [ 33 , 41 ]. A large number of companies have adopted the reduce-reuse-recycle approach, understanding that solving social and environmental issues require changing the strategy of organizations and introducing interdisciplinary actions and methods [ 38 ].…”

“…The circular and sustainable bioeconomy is gaining traction as a means of addressing climate change and fossilization, increasing resource efficiency and creating new opportunities for long-term economic growth [ 33 ].…”