College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China.
Appl Biochem Biotechnol. 2012 Sep;168(1):58-67. doi: 10.1007/s12010-011-9323-y. Epub 2011 Jul 26.
Using low-cost raw material is an effective approach for reducing the cost of cellulolytic enzymes. The farmland waste corncob was found in this study to be the best carbon source for the production of β-glucosidase by Aspergillus niger. The maximum yield of β-glucosidase activity was 48.7 IU ml(-1) by using 50 g l(-1) of corncob powder as the substrate. It was found that the water-soluble components of the corncob could increase β-glucosidase production significantly only when mixed with Avicel or wheat bran. The soluble components could not enhance the biomass and β-glucosidase production when used alone. On the other hand, the water-insoluble components of the corncob still produced high level of β-glucosidase (30 IU ml(-1)) although lower than that of using whole corncob. The results suggested that the water-insoluble components of corncob were beneficial for β-glucosidase production. It was further demonstrated that the xylan in the water-insoluble parts of corncob was the important factor in producing β-glucosidase by A. niger.
使用低成本的原材料是降低纤维素酶成本的有效方法。本研究发现，农田废弃物玉米芯是黑曲霉生产β-葡萄糖苷酶的最佳碳源。当以 50g/L 的玉米芯粉作为底物时，β-葡萄糖苷酶的最大酶活产率为 48.7IU/ml。结果表明，只有当玉米芯的水溶性成分与 Avicel 或麦麸混合时，才能显著提高β-葡萄糖苷酶的产量。当单独使用水溶性成分时，不能提高生物量和β-葡萄糖苷酶的产量。另一方面，玉米芯的水不溶性成分仍能产生较高水平的β-葡萄糖苷酶（30IU/ml），尽管低于使用整颗玉米芯的水平。结果表明，玉米芯的水不溶性成分有利于β-葡萄糖苷酶的生产。进一步证明玉米芯水不溶性部分的木聚糖是黑曲霉产生β-葡萄糖苷酶的重要因素。
