Abstract: Ultrasound was applied to rupture the cells of Brevibacilllus brevis FJAT-0809-GLX to facilitate extraction of the intracellular metabolites produced by the bacteria.Effect of ultrasonic power,treatment time,and cell/liquid ratio were studied in a single-factor experiment.Optimum conditions of the extraction were determined using a design-expert program and the response surface method.The single-factor experiment showed that,when the ultrasonic treatment time was 30 min,the greatest recovery rate on the intracellular metabolites,i.e.,11mg·g^-1,could be obtained;when 100 W of ultrasound power was applied,the highest extraction rate of9.33mg·g^-1 was achieved;and,when a cell/liquid ratio was 1∶25implemented,the highest yield of 12.22mg·g^-1 could be reached.Then,the process was optimization by using the response surface method to show that the effects were cell/liquid ratio>ultrasonic application time>ultrasonic power,and the optimal conditions for the ultrasonic disruption were:an application of ultrasonic power at 318.68 W,a total treatment time of 10 min,and a cell/liquid ratio of 1∶25.As a result,ayield of the intracellular metabolites from the extraction at 12.987 8mg·g^-1 was achieved.