Continuous production of inulo-oligosaccharides from chicory juice by immobilized endoinulinase

Several carrier materials were examined for endoinulinase immobilization. A polystyrene carrier material (UF93(R)) gave the best immobilization capaci ty (217 units/g carrier) and operational stability. Carbohydrate compositio ns in the reaction product were quite similar irrespective of the support m aterials even though each carrier material has different pore structure ass ociated with diffusional restriction. After immobilization the optimal pH f or enzyme activity was shifted from 5.0 to 4.5, whereas optimal temperature (55 degrees C) was unaltered. Continuous production of inulo-oligosacchari des from chicory juice was carried out using the polystyrene-bound endoinul inase. The recommended operating conditions of the enzyme reactor for maxim izing productivity were as follows: feed concentration, 100 g/l chicory jui ce; flow rate, as superficial space velocity 2.0 h(-1); temperature, 55 deg rees C. The enzyme reactor was run for 28 days at 55 degrees C achieving an oligosaccharide yield of 82% without any significant loss of initial enzym e activity, where the volumetric productivity was 200 g/l . h. Furthermore, there was no marked difference in operational stability between the two re actors fed with pure inulin solution and with chicory juice as a substrate even though chicory juice contains a lot of impurities.