摘要

可再生果胶酶纳米高分子颗粒

作者(年代):raddvan Say, Ercan Çınar， Özlem Biçen Ünlüer和Arzu Ersöz

果胶酶或果胶溶解酶是一组降解果胶物质的酶。它们在食品工业中具有重要的意义，特别是对于水果清粉的装配。本研究利用纳米果胶酶颗粒对果胶进行水解，提出了果胶水解的替代方法。在研究的第一阶段，采用氨基烷烃酸(单体)修饰和轻量衬底共轭法(ANADOLUCA)合成了纳米果胶酶颗粒，并通过透射显微镜(TEM)和zeta施胶仪进行了表征。在第二步中，分别使用新合成的纳米果胶酶颗粒和游离果胶酶对果胶的水解进行了研究，并与其他方法进行了比较。考察了影响果胶水解的各种条件，如pH值、热稳定性、储存稳定性和重复使用性。然后，用Michaelis- Menten参数对纳米果胶酶颗粒和游离果胶酶的活性进行了比较分析。此外，与游离酶相比，纳米果胶酶颗粒的可重复使用性数据显示出作为可重复使用催化剂的良好潜力。因此，新合成的纳米果胶酶颗粒对果胶物质的水解具有很好的应用前景。磁性壳聚糖颗粒是按照三种不同的方案制备的，能够制备不同大小的颗粒-纳米(nano - cmag)，微型(Micro- cmag)和宏观(Macro- cmag) -并用于果胶酶固定化和澄清葡萄、苹果和橙汁。 The particle size had an excellent effect within the kinetic parameters, Nano-CMag biocatalyst presented the very best Vmax value (78.95 mg. min−1), followed by Micro-CMag and Macro-CMag, with Vmax of 57.20 mg.min−1 and 46.03 mg.min−1, respectively. However, the very best thermal stability was achieved using Macro-CMag, that was 8 and 3-times more stable than Nano-CMag and Micro-CMag biocatalysts, respectively. Pectinase immobilized on Macro-CMag kept 85% of its initial activity after 25 batch cycles in fruit juice clarification. These results suggested that the chitosan magnetic biocatalysts presented great potential application as clarifying catalysts for the fruit crush industry and therefore the great importance of the chitosan particles preparation on the ultimate biocatalyst properties. Freshly pressed apple, orange and grape juices with none treatment were kindly provided by Vitivinícola Jolimont (Canela, RS, Brazil). Rohapect 10 L was from Amazon group (Brazil). Pectin from apple, polygalacturonic acid, galacturonic acid and chitosan were purchased from Sigma-Aldrich (St. Louis, MO). All other reagents and solvents were of analytical grade. A yeast strain secreting endopolygalacturonase was utilized in this work to review the likelihood of continuous production of this enzyme. it's a feasible and interesting alternative to fungal batch production essentially thanks to the specificity of the sort of pectinase excreted by Kluyveromyces marxianus CCT 3172, to the lower broth viscosity and to the better downstream operations. so as to extend the reactors' productivity, a cellulosic carrier obtained from barley spent grains was tested as an immobilization support. Two sorts of reactors were studied for pectinase production using glucose as a carbon and energy source--a continuous stirred tank reactor (CSTR) and a packed bed reactor (PBR) with recycled flow. the very best value for pectinase volumetric productivity (P(V)=0.98 U ml(-1) h(-1)) was achieved within the PBR for D=0.40 h(-1), a glucose concentration on the inlet of S(in)=20 g l(-1), and a biomass load within the support of X(i)=0.225 g g(-1). The results demonstrate the attractiveness of the packed bed system for pectinase production.

关键词:纳米果胶酶颗粒;ANADOLUCA方法;可重复使用的催化剂;光敏交联