Abstract: We here present a novel method to extract non-degraded β-D-glucans from spent yeast cells, mainly based on induced yeast autolysis, hot water extraction, cell wall disruption, defatting and protease hydrolysis. One-factor-at-a-time coupled with orthogonal array design method was applied to the process conditions of induced yeast autolysis and cell wall disruption. The extract obtained under optimized conditions had a total sugar content of 84.9% with an extraction yield of 13.7%. Its purity and yield were both higher than previously reported. Induced yeast autolysis and hot water extraction had a significant effect on β-D-glucan purity and yield. Moreover, protease treatment could further remove protein impurities and increase β-D-glucan purity. The absence of strong acid, strong alkali and oxidant throughout the process helped to protect the physiological activity of products and the environment.

Key words: spent yeast cell, β-D-glucans, non-degradative extraction