Preparation and characterization of insoluble β-glucan from waste beer yeast.

The management of brewery waste, particularly waste brewer's yeast, has posed a significant environmental and economic challenge. This study proposed an approach to valorize waste brewer's yeast by extracting β-glucan. The key phases of the research included yeast autolysis, alkaline treatment and optimization of the β-glucan purification conditions. The findings revealed that a 0.7 % NaOH concentration at 80 °C for 2.6 h was the most effective for impurity removal. In the comparative analysis, it was confirmed that extraction at 80 % DMSO concentration with a 30:1 solid-liquid ratio at 80 °C for 30 min was the optimal condition for obtaining high-purity β-glucan. The process yielded a β-glucan high purity of 95.84 ± 1.15 % and a yield of 5.56 ± 0.34 % based on the wet weight after centrifugation. The structure was analyzed using TLC, FTIR and NMR. The extracts are polysaccharides composed of glucose monomers linked by β-glycosidic bonds. In addition, It has demonstrated significant anti-inflammatory properties in vitro and can be developed as a functional food. This study provides a feasible and efficient solution for the sustainable utilization of waste brewer's yeast, contributing to environmental sustainability and offering economic benefits for the brewing industry.