Biotechnology Center in Southern Taiwan, Academia Sinica, 2F, No. 22, Lane 31, Sec. 1, Huandong Rd., Sinshih Township, Tainan 74146, Taiwan, ROC.
Bioresour Technol. 2010 Feb;101(4):1310-7. doi: 10.1016/j.biortech.2009.08.049. Epub 2009 Oct 17.
A high yield of beta-glucosidase (EC 3.2.1.21) of 159.1 U/g-solid activity on 4-nitrophenyl beta-d-glucopyranoside (pNPG) was achieved by rice bran-based solid-state fermentation (SSF) of the recently characterized fungus Penicillium citrinum YS40-5. The enzyme was both thermophilic and acidophilic at the optimized temperature and pH of 70 degrees C and 5.0, respectively. Over 95% of the original beta-glucosidase activity was maintained after a prolonged storage at ambient temperature for 4 weeks. The kinetic parameters V(max), K(m) and K(I) were 85.93 U/mg, 1.2 mM and 17.59 mM with pNPG, and 72.49 U/mg, 32.17 mM and 8.29 mM with cellobiose, respectively. The protein band with beta-glucosidase activity was characterized by native PAGE followed by MUG-zymogram analysis, and its identity confirmed by nanoLC-MS/MS. A 3.43-fold synergistic effect by combining this beta-glucosidase with Trichoderma reesei cellulases was observed, indicating this enzyme could potentially be used for improving the efficiency of cellulosic bioconversion.
采用最近鉴定的青霉（Penicillium citrinum）YS40-5 进行米糠固态发酵（SSF），可获得高达 159.1 U/g 固体活性的 4-硝基苯-β-D-葡萄糖苷（pNPG）β-葡萄糖苷酶（EC 3.2.1.21）。该酶在优化的温度和 pH 值 70°C 和 5.0 下均为嗜热和嗜酸。在环境温度下储存 4 周后，仍保持超过 95%的原始β-葡萄糖苷酶活性。与 pNPG 相比，动力学参数 V(max)、K(m)和 K(I)分别为 85.93 U/mg、1.2 mM 和 17.59 mM，与纤维二糖相比，V(max)、K(m)和 K(I)分别为 72.49 U/mg、32.17 mM 和 8.29 mM。通过天然 PAGE 后进行 MUG-酶谱分析，对具有β-葡萄糖苷酶活性的蛋白质带进行了表征，并通过 nanoLC-MS/MS 对其进行了鉴定。当与里氏木霉纤维素酶结合使用时，观察到 3.43 倍的协同效应，表明该酶可能有潜力用于提高纤维素生物转化的效率。
