黑曲霉发酵豆渣产酸性β-葡萄糖苷酶及其水解京尼平苷的性质  

Production and Characterization of Acid Geniposide-hydrolyzing β-Glucosidase from Aspergillus niger L. Incubated on Soybean Dregs

作　　者：王剑锋[1] 徐琼[1] 肖志强[1] 余奇峰[1] 钱皇辉[1] 熊飞飞[1] 

机构地区：[1]东华理工大学生物系,江西抚州344000

出　　处：《林产化学与工业》2011年第1期35-40,共6页Chemistry and Industry of Forest Products

摘　　要：利用单因素、正交试验考察了黑曲霉L菌株发酵豆渣产β-葡萄糖苷酶的条件和酶解京尼平苷的特性。结果表明:2%豆渣适宜作为实验菌株液体发酵产酶培养基,当培养基中接种孢子浓度大于每毫升2×105个时,菌株产酶受发酵温度、装液量的影响显著,而不受接种量、摇床转速的影响,培养基初始pH值1.5时,菌株仍能正常产酶;优化的产酶培养基组成为豆渣1%、米糠1%和Tween 800.1%,初始pH值5.5;菌株在发酵温度28℃、装液量50 mL(250 mL摇瓶)、摇床转速150 r/min的发酵条件下发酵120 h,发酵液酶活为(200±10)U/mL。所产β-葡萄糖苷酶水解京尼平苷的最适温度为55℃、最适pH值2.5、最佳水解时间15 min;在该条件下酶的表观米氏常数(Km)为1.35 g/L,最大水解速率(Vmax)为26.45 g/(L.min.mg),酶活半衰期为15 min,50℃时大于60 min;酶的水解活性受Na+、Ca2+的显著激活,受Mg2+、Ba2+、Cu2+、Fe2+、Hg+、Zn2+、Mn2+等离子(10 mmol/L)和葡萄糖、乙醇的抑制。By culturing Aspergillus niger L. , which was isolated from mouldy gardenia fruits, in broth with soybean dregs 2 % , an acidic geniposide-hydrolyzingβ-glucosidase was produced. When inoculated spore concentration reached to 2 x 10^5/mL, the productivity was impacted significantly by both fermentation temperature and broth content. However, it was not impacted by inoculum size and rotation speed, even if the initial pH value of broth was 1.5. Under the optimal culture conditions which were fermentation temperature 28 ℃, initial pH value 5.5, broth content 50 mL/250 mL, rotation speed 150 r/min and cultivation time 120 h, and in the optimized medium containing soybean dregs 1% , rice bran 1% and Tween 80 0.1% , the resulting fl-glueosidase activity was up to（200 ± 10） U/mL. The activity for β-glucosidase hydrolyzing geniposide reached the maximum at pH value 2. 5, the appropriate temperature 55℃ and the best hydrolysis time 15 min, with Km, Vmax and half-life being 1.35 g/L, 26.45 g/（ L. min-mg, protein） and 15 min, respectively. The activity was activated by Na＋ and Caz＊ , and inhibited at different degrees by Mg^2＋, Ba^2＋, Cu^2＋, Fe^2＋, Hg^＋, Zn^2＋, Mn^2＋ and Hg^2＋ at 10 mmol/L, as well as inhibited by glucose and ethanol.

关 键 词：Β-葡萄糖苷酶 豆渣 对硝基苯-β-D吡喃葡萄糖苷 京尼平 黑曲霉 

分 类 号：TQ351[化学工程]