Abstract

Inulinase was immobilised by entrapment method in polyacrylamide/polyethylene glycol composite and evaluated for its efficiency for short-chain fructooligosaccharides (3–6 degrees of polymerisation) production in batch hydrolysis system. Aqueous two-phase polymerisation technique was used to synthesise the composite, where aqueous polyethylene glycol 1000 containing the enzyme was used as dispersant with ammonium persulfate as initiator. The characteristics of free and immobilised inulinase were investigated and compared, and the results showed shift of pH and temperature optimum and change in stability caused by the immobilisation material. The immobilised preparation retained 50% of its initial activity after 20 successive batch cycles of 1 h each. The conversion degree of highly polymerised inulin to fructooligosaccharides (3–6 degrees of polymerisation) was 36% when using 30% PAA/PEG, w/v.

• Highlights

• ATPS extracted inulinase was effectively immobilised in PAA/PEG composite.

• Immobilised enzyme showed good pH and thermal stability.

• Immobilised catalyst presents good retention of activity after 20 reuses.

• The entrapped enzyme is effective in producing FOS with the DP from 3 to 6 with proved prebiotic activities.

• The optimum conditions for batch operating mode were: 2% (w/v) inulin, 30% (w/v) PAA/PEG composite, pH = 4.4 and T = 40ºC.

摘要

通过包埋法将菊粉酶固定在聚丙烯酰胺/聚乙二醇复合材料中，并评估其在间歇水解系统中生产短链低聚果糖（3-6 度聚合度）的效率。使用水两相聚合技术合成复合材料，其中含有酶的水性聚乙二醇1000用作分散剂，过硫酸铵作为引发剂。对游离和固定化菊粉酶的特性进行了研究和比较，结果表明固定化材料引起的最适pH和温度的变化以及稳定性的变化。固定化制剂在 20 个连续批次循环（每次 1 小时）后保留了 50% 的初始活性。

• 强调

• ATPS提取的菊粉酶被有效地固定在PAA/PEG复合物中。

• 固定化酶表现出良好的pH和热稳定性。

• 固定化催化剂在重复使用 20 次后表现出良好的活性保留。

• 包埋的酶可有效地产生 DP 为 3 至 6 的果寡糖，并具有已证实的益生元活性。

• 批量操作模式的最佳条件是：2% (w/v) 菊粉，30% (w/v) PAA/PEG 复合材料，pH = 4.4 和T  = 40ºC。