Valorisation of Brewer’s Spent Grain: Lignocellulosic Fractionation and its Potential for Polymer and Composite Material Applications

An estimated amount of 40 million t/a of Brewer’s Spent Grain (BSG) is produced and is currently used for low-value valorisation or disposed of in landfills. In an era where non-renewable resources stocks are depleting and products such as plastics accumulate in the environment, the need for more sustainable resources, products and production strategies is substantial. Lignocellulosic biomasses, when their production is not in competition with the food sector, could be an answer to this challenge through the use of biorefineries. This review aims at gathering the advantages of BSG’s valorisation through the prism of building block production for polymer synthesis and its use as natural filler for composite material. BSG will also be compared to other biomasses by exploring the conditions available for its fractionation. The examples listed herein depict promising valorisation strategies with a myriad of building blocks available for the synthesis of organic compounds and polymers. The use of BSG as filler in composite materials, however, faces limitations in terms of performances that will need to be tackled in future works. A lot of research has yet to be performed on BSG’s valorisation to help shift the polymer and material industry towards a more sustainable horizon.