Abstract

Jerusalem artichoke (JA) is a nutritional vegetable for human diet depending on its natural structure, especially high inulin content and it is the second inulin source for commercial production in the world, after chicory. It was aimed to investigate the inulinase production capability of Galactomyces geotrichum TS61 (GenBank accession: MN749818) using JA as an economical and effective substrate comparing with the pure chicory inulin and to optimize the fermentation using Taguchi design of experiment (DOE) in this study. Besides, the effects of sucrose on inulinase production either combined with JA or in its absence were also studied. Taguchi L16 orthogonal array was employed for optimization. Both of inulinase activities obtained from JA and pure inulin gave the maximum result at the 10th experimental run as 40.21 U/mL and 57.35 U/mL, respectively. The optimum levels were detected for each factor as, 30 g/L JA, 30 g/L sucrose, pH 5.5, and four days for time. The predicted value was found as 41.63 U/mL that was similar to the obtained result as 41.17 U/mL. Finally, inulinase activity was increased approximately 8-folds after optimization. The sucrose-free medium had similar effects with higher concentrations of JA at long incubation time. This is the first investigation about inulinase production by G. geotrichum.

 抽象的

菊芋（JA）因其天然结构，特别是高菊粉含量而成为人类膳食的营养蔬菜，是继菊苣之后世界上第二个商业化生产的菊粉来源。本研究旨在考察地霉半乳糖（ Galactomyces geotrichum TS61）（GenBank登录号：MN749818）以JA为经济有效的底物与纯菊苣菊粉相比的菊粉酶生产能力，并利用田口实验设计（DOE）优化发酵。此外，还研究了蔗糖与 JA 联合使用或单独使用时对菊粉酶生产的影响。采用田口L16正交阵进行优化。从 JA 和纯菊粉获得的菊粉酶活性均在第 10 次实验运行时给出最大结果，分别为 40.21 U/mL 和 57.35 U/mL。检测到每个因子的最佳水平为：30 g/L JA、30 g/L 蔗糖、pH 5.5 和四天时间。预测值为 41.63 U/mL，与所得结果 41.17 U/mL 相似。最后，优化后菊粉酶活性提高了约 8 倍。无蔗糖培养基在较长的孵育时间内具有较高浓度的 JA 类似的效果。这是对地霉生产菊粉酶的首次研究。