王剑锋 1徐琼 1肖志强 1余奇峰 1钱皇辉 1熊飞飞1
作者信息
- 1. 东华理工大学生物系,江西抚州,344000
- 折叠
摘要
Abstract
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 × 105/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 β-glucosidase activity was up to( 200 ± 10) U/mL.The activity forβ-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 Ca2+ , and inhibited at different degrees by Mg2+, Ba2+, Cu2+, Fe2+, Hg+, Zn2+, Mn2+ and Hg2+ 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Key words
β-glucosidase/ soybean dregs /p-nitrophenyl-β-D-glucopyranoside/ genipin /Aspergillus niger L.分类
化学化工
