发酵耦合酶解高效制备右旋糖酐工艺研究

Study on Efficient Preparation for Dextran by Fermentation Coupled with Enzymatic Hydrolysis

关键词:  右旋糖酐  酶法  右旋糖酐酶  流加

Key words:  dextran  enzymic method  dextranase  feeding

摘要:

[目的]改进肠膜明串珠菌(Leuconostoc mesenteriodes 31208)发酵蔗糖制备右旋糖酐的工艺,实现灵活控制分子量及高效制备右旋糖酐的目标。[方法]采用单因素实验法研究蔗糖浓度对蔗糖转化的影响,确定蔗糖流加工艺的各个参数,以及右旋糖酐酶添加耦合蔗糖流加的工艺条件。[结果]通过调控右旋糖酐酶添加工艺,可灵活控制右旋糖酐的分子量,无需再经酸水解及乙醇分级沉淀就可以得到不同分子量的右旋糖酐,节省无水乙醇的用量;且确定的最佳蔗糖流加工艺参数:初始蔗糖浓度为130 g/L,流加速度为12 g·L^-1·h^-1,起始流加时间为16 h。与蔗糖单批发酵结果相比,该工艺可使蔗糖转化效率提高约75%,特定分子量(5000~7500 Da)右旋糖酐浓度可达108 g/L,相应提高2.3倍,收率稳定在32%左右。[结论]该方法具有发酵易调控、高效和成本低的优点,对大规模生产右旋糖酐具有重要的参考价值和应用价值。

Abstract:

[Objective] This paper aims to control dextran molecular flexibly and prepare dextran efficiently with Leuconostoc mesenteriodes 31208 by improving the preparation process.[Methods] The effect of sucrose concentration on sucrose conversion, the parameters of sucrose feeding, as well as the process conditions coupled enzymatic adding and sucrose feeding were studied by means of single factor experiment.[Results] The molecular weight of dextran was controlled flexibly by changing the enzymatic hydrolysis process, and the parameters of optimal sucrose feeding process were the initial sucrose concentration of 130 g/L with the flow acceleration of 12 g·L^-1·h^-1 at 16 h.Compared with the single batch fermentation, the conversion rate improved by 75% and specific-molecular dextran (5000~7500 Da)increased over time, and the yield of dextran was about 32%.[Conclusion] This method has the characteristics of simple fermentation control, high efficiency and low cost, which was important to the preparation of dextran for industrial production.