Xylooligosaccharides (XOs) production from xylan, extracted from coffee parchment, using two stirred tank reactors (STRs) and two membrane bioreactors (MBRs) was studied for the first time. In the reactors, xylanase either free in a solution (E-STR, E-MBR) or covalently immobilized on magnetic nanoparticles (MNP-STR, MNP-MBR) was used. A continuous production of reducing sugars in both MBRs was obtained. In the E-MBR, the same conversion of E-STR at a low substrate concentration (1 mg mL^–1) (97%) was obtained. At higher substrate concentration, the conversion increases by a quarter in E-MBR on increasing the residence time and doubles in MNP-MBR by increasing the amount of immobilized enzyme. The unchanged apparent K_M (about 8 mg mL^–1) showed that the affinity of the enzyme for the substrate was not altered by the immobilization process. In E-MBR, the enzyme/substrate affinity is even improved (K_M: 2.58 mg mL^–1), thanks to the continuous removal of the inhibition products, present in the initial xylan solution, by the membrane process.

中文翻译：

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膜生物反应器中咖啡羊皮纸上木聚糖的酶促水解

首次研究了使用两个搅拌釜反应器（STR）和两个膜生物反应器（MBR）从咖啡羊皮纸中提取的木聚糖生产的木寡糖（XO）。在反应器中，使用在溶液中游离的木聚糖酶（E-STR，E-MBR）或共价固定在磁性纳米颗粒上的木聚糖酶（MNP-STR，MNP-MBR）。在两个MBR中均获得了连续的还原糖生产。在E-MBR中，在低底物浓度（1 mg mL ^–1）（97％）下获得了相同的E-STR转化率。在较高的底物浓度下，随着停留时间的增加，E-MBR的转化率增加四分之一，而通过增加固定化酶的量，MNP-MBR的转化率增加一倍。不变的表观K _M（约8 mg mL ^–1）表明酶对底物的亲和力没有被固定过程改变。在E-MBR中，由于通过膜工艺连续去除了最初的木聚糖溶液中存在的抑制产物，因此酶/底物的亲和力甚至得到了改善（K _M：2.58 mg mL ^–1）。