期刊
APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY
卷 171, 期 4, 页码 832-846出版社
SPRINGER
DOI: 10.1007/s12010-013-0402-0
关键词
Aspergillus niger; Glycoside hydrolase; Carbon source; Dynamic zymography assay; Hydrolysates of lignocellulose
资金
- Major State Basic Research Development Research Program of China [2011CB707401]
- National Natural Science Foundation of China [30970092, 31170071]
Aspergillus niger is an effective secretor of glycoside hydrolases that facilitate the saprophytic lifestyle of the fungus by degrading plant cell wall polysaccharides. In the present study, a series of dynamic zymography assays were applied to quantify the secreted glycoside hydrolases of A. niger cultured in media containing different carbon sources. Differences in the diversity and concentrations of polysaccharide hydrolysates dynamically regulated the secretion of glycoside hydrolases. The secretion of beta-1,4-endoglucanase isozymes was observed to lag at least 24 h behind, rather than coincide with, the secretion of xylanase isozymes. Low concentrations of xylose could induce many endoxylanases (such as Xyn1/XynA, Xyn2, and Xyn3/XynB). High concentrations of xylose could sustain the induction of Xyn2 and Xyn3/XynB but repress Xyn1/XynA (GH10 endoxylanase), which has a broad substrate specificity, and also triggers the low-level secretion of Egl3/EglA, which also has a broad substrate specificity. Mixed polysaccharide hydrolysates sustained the induction of Egl1, whereas the other beta-1,4-endoglucanases were sustainably induced by the specific polysaccharide hydrolysates released during the hydrolysis process (such as Egl2 and Egl4). These results indicate that the secretion of glycoside hydrolases may be specifically regulated by the production of polysaccharide hydrolysates released during the process of biomass degradation.
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