Turning Brewery Waste into Paper: Brewer’s Spent Grain as an Alternative Fiber in Sustainable Paper Innovation

Brewer's spent grain is a significant byproduct of the brewing industry, composed mainly of cellulose, hemicelluloses, lignin, and polysaccharides (arabinoxylans). It is primarily used for agricultural purposes, such as animal feed. However, it also presents an alternative option as a substitute for wood cellulose in certain paper grades. This study investigates the strength contribution of mechanically macerated BSG at different amendment levels and evaluates its potential application in producing paper products. The tensile index decreased by 46% when 40% BSG was substituted. However, 20% of the tensile index was recovered through the addition of strength and retention aids. This indicates that BSG may be used in certain paper grades in combination with a suitable wet end chemistry package without significant degradation of mechanical properties.