Galactosyl-oligosaccharides (GOS) are non-digestible oligosaccharides which are qualified as functional foods. GOS are enzymatically synthesized from lactose by transgalactosylation catalyzed by the enzyme β-galactosidase. In this study, a method for immobilization of β-galactosidase from Kluyveromyces lactis on a chromatography membrane was developed. The immobilization was performed at 4, 15 and 40°C. A strong basic anion exchange membrane was investigated. In static experiments the highest enzyme activity was measured at an immobilization procedure temperature of 15°C. The immobilization on the chromatography membranes was found to be very rapid likely due to ionic adsorption. The synthesis of GOS was carried out in a Continuous Membrane Chromatography Reactor System (CMCRS) at 40°C and pH 7.0 using 20 wt% initial lactose concentration. The chromatography membranes proved to be a good support for the continuous process at high convective flow rates in the enzyme reactor system. Up to 82 % lactose conversion with 24 % GOS yield was achieved at different fluxes. The corresponding reactor productivity for the production of GOS from lactose in the CMCRS was 98.7 g GOS per hour and cubic centimeter membrane volume, which significantly exceeds previously reported results.
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机译：半乳糖低聚糖（GOS）是不可消化的低聚糖，属于功能食品。通过由β-半乳糖苷酶催化的反式半乳糖基化反应，由乳糖酶促合成GOS。在这项研究中，开发了一种将来自乳酸克鲁维酵母的β-半乳糖苷酶固定在色谱膜上的方法。固定在4、15和40℃下进行。研究了一种强碱性阴离子交换膜。在静态实验中，最高的酶活性是在15°C的固定过程温度下测得的。发现可能由于离子吸附而非常快速地固定在色谱膜上。在连续膜色谱反应器系统（CMCRS）中，初始乳糖浓度为20 wt％的情况下，在40°C和pH 7.0下进行GOS的合成。色谱膜被证明是酶反应器系统中高对流流速下连续过程的良好支撑。在不同通量下，乳糖转化率高达82％，GOS产率为24％。在CMCRS中由乳糖生产GOS的相应反应器生产率为每小时98.7 g GOS和立方厘米膜体积，这大大超过了先前报道的结果。
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