TRANSFORMING BREWER’S SPENT GRAIN INTO VALUE-ADDED BIODEGRADABLE PRODUCTS

Brewer's spent grain (BSG) can be used to produce biodegradable plastics and sweeteners through several pathways.This study presents a simulation-driven biorefinery model for converting this kind of waste into two commercially significant biochemicals: polylactic acid (PLA) and Xylitol.Brewer's spent grains are by-product of the brewing industry, and being produced in large quantities but remain significantly underutilized.They content a lot of polysaccharides and proteins, offering so a valuable potential for biotechnological transformation.Firstly, BSG was considered to be treated with dilute acid to hydrolyze hemicellulose into xylose-rich hydrolysate, under of ~120C, 30 min, 1.7-2 M acid concentration, following by Xylitol fermentation in the presence of microorganisms obtaining a substrate based in Xylose-rich hydrolysate, at the conditions: pH ~5.8-6.8;temperature ~37C; incubation ~80 h.Then, was previewed a Lactic Acid fermentation in the presence of microorganism and as substrate was Glucose-rich cellulose hydrolysate with the conditions: pH ~5.7; temperature ~37C; with varying incubation time.BSG's lignocellulosic composition makes it a versatile feedstock: for biodegradable plastics by direct incorporation into composites or via conversion to polymer building blocks; and for sweeteners by enzymatic breakdown of hemicellulose to fermentable sugars like xylose for xylitol production.Simulation results estimate production yields of approximately 0.3 kg of PLA and 0.2 kg of Xylitol per kg of dry BSG, with fermentation efficiencies reaching up to 80% under optimized conditions.A preliminary techno-economic assessment projects an internal rate of return (IRR) exceeding 15% and a payback period of fewer than five years, indicating the process's financial feasibility.The process design contributes to waste valorization, resource efficiency, and green chemistry innovation.