棘孢曲霉固态发酵α-L-鼠李糖苷酶调控机制及培养基优化

The Regulatory Mechanisms of α-L-rhamnosidase Synthesis from Aspergillus aculeatus and Improving the Medium for α-L-rhamnosidase Production Using Solid-state Fermentation

为了提高α-L-鼠李糖苷酶的发酵产量,利用高效液相色谱法检测α-L-鼠李糖苷酶活力,考察外加碳源葡萄糖、氮源及生长因子对棘孢曲霉JMUdb058固态发酵产α-L-鼠李糖苷酶的调控机制,并以之为依据优化培养基。研究结果表明,葡萄糖和淀粉对α-L-鼠李糖苷酶的产生具有代谢调节作用;外加氮源能大幅度提高α-L-鼠李糖苷酶的活力;相比用硫酸铵为氮源,用豆饼粉为氮源时,由于其中含有淀粉而导致酶合成量降低;磷酸氢二铵比其他铵盐和硝酸盐更能促进α-L-鼠李糖苷酶的合成。添加富含氨基酸的生长因子有利于α-L-鼠李糖苷酶的合成。棘孢曲霉JMUdb058发酵产α-L-鼠李糖苷酶优化后的培养基是:柚皮5 g,磷酸氢二铵0.5 g,酵母浸膏0.075 g,水5 m L,此时α-L-鼠李糖苷酶活力达到10.60 IU/gds,比初始培养基的酶活力提高了84.67%,比其他文献报道的最高酶产量提高了1.5倍。优化后的培养基大幅度提高了棘孢曲霉固态发酵α-L-鼠李糖苷酶的活力,为该酶的发酵生产及开发利用提供了技术参考。

In this study, the activity of α-L-rhamnosidase was detected by HPLC, the regulatory effects of glucose,nitrogen source and growth factors on the induction of α-L-rhamnosidase were investigated, and the medium was improved for the production of this enzyme from Aspergillus aculeatus JMUdb058 by solid-state fermentation. The results showed that glucose had strong metabolic inhibitory effect on the induction of α-L-rhamnosidase from A. aculeatus. The addition of nitrogen source significantly enhanced the production of α-L-rhamnosidase. Furthermore, in comparison to ammonium sulfate, the addition of organic nitrogen source soybean meal showed a lower activity of α-L-rhamnosidase,which was revealed in light of it contained large amount of starch that inhibited the induction of the enzyme. Among the inorganic nitrogen sources tested, diammonium hydrogen phosphate had the most effectiveness in α-L-rhamnosidase synthesis. The production of α-L-rhamnosidase could further increase by the addition of some growth factors that enriched in amino acids. The solid-state fermentation of an improved medium that consisted of pomelo peel powder（5 g）, diammonium hydrogen phosphate（0.5 g）, yeast extract（0.075 g） and water（5 m L） showed an α-L-rhamnosidase activity of 10.60 IU/gds, which increased by 84.67% and 1.5 times in comparison with the initial medium and the most effective process reported by other researcher＇s, respectively. This paper illustrated the regulatory mechanisms of glucose, nitrogen source and growth factor on the synthesis of α-L-rhamnosidase, by which the production of α-L-rhamnosidase was, increased significantly. These results provide a practical technique for the production of α-L-rhamnosidase.