Abstract: In order to develop and utilize waste beer yeast resources,this experiment was designed to extract trehalose from waste beer yeast with ultrasonic-assisted water extracton technology. The extraction factors such as solid-liquid ratio,ultrasonic treament time,ultrasonic power,extraction time and water temperature were investigated through comparison analysis and L9(34) orthogonal design. The results indicated that the most significant factor is extraction temperature,followed by extraction time,ultrasonic power and ultrasound treament time in turn. The optimal extraction conditions are as follows:ultrasound treatment time 20 min,ultrasonic power 600 W,water extraction time 6 h and extraction temperature 100 ℃. Under these optimal conditions,the extraction rate of trehalose could reach 7.72%. Compared with ethanol extraction,the ultrasonic-assisted water extraction technology can greatly reduce cost.

Key words: ultrasonic, waste beer yeast, trehalose, extraction