The production of high-content fructo-oligosaccharides from sucrose by the mixed-enzyme system of beta-fructofuranosidase and glucose oxidase was investigated. The mixed-enzyme reaction was carried out in a stirred tank reactor containing 0.7 1 of sucrose solution with coupled beta-fructofuranosidase and glucose oxidase for 25 h. The optimum conditions for the mixed-enzyme reaction were as follows : pH, 5.5; temperature, 40-degrees-C; sucrose concentration, 400 g/l; agitation speed, 550 rpm; oxygen flow rate, 0.7 l/min; enzyme dosage, 10 units of beta-fructofuranosidase with the combination of 15 units of glucose oxidase per gram sucrose. Under optimum conditions, high-content fructo-oligosaccharides up to 98% were obtained with complete consumption of sucrose and glucose by the mixed-enzyme system. Compared with the fructo-oligosaccharides produced by the beta-fructofuranosidase, the high-content fructo-oligosaccharides produced by the mixed-enzyme system showed a significant difference with respect to sugar composition; i.e., a higher content of nystose was accumulated and only a trace amount of fructofuranosyl nystose was detected.