农作物秸秆中大量存在的纤维素是可再生的清洁能源之一,纤维素的充分利用对于自然资源的可持续发展及环境保护有重要意义。然而,秸秆中纤维素的复杂结构使其降解工作较难开展。扩展蛋白是存在于植物及部分微生物中的一类细胞壁松弛蛋白,且来自于微生物中的扩展蛋白被证实能够提高纤维素酶的水解效率。为探究植物中扩展蛋白协同纤维素酶提高降解纤维素的能力,该研究以冬小麦扩展蛋白TaEXPA8为基础构建了黑曲霉表达载体,并以黑曲霉CICC2462为受体获得了黑曲霉工程菌pSZHGS-TaEXPA8,同时对该工程菌发酵液的纤维素水解促进作用进行了分析。结果显示,TaEXPA8基因能够在工程菌中进行正常的转录,并在发酵上清液中检测到TaEXPA8蛋白的表达,但表达量较低;工程菌的发酵液能够显著促进滤纸的崩解,水解作用产生葡萄糖的含量相比于单一纤维素酶处理提高了21.2%。该研究为植物扩展蛋白在纤维素降解中的应用提供新的思路和方法。
王雪
,
冯旭
,
贺付蒙
,
徐永清
,
袁强
,
李丽
,
刘丹
,
孔德兴
,
李凤兰
. 冬小麦扩展蛋白TaEXPA8黑曲霉工程菌的构建及纤维素水解作用分析[J]. 食品与发酵工业, 2022
, 48(2)
: 219
-223
.
DOI: 10.13995/j.cnki.11-1802/ts.027464
Cellulose, which is abundantly present in crop stalks, is one of the renewable clean energy sources. The full utilization of cellulose is of great significance to the sustainable development of natural resources and environmental protection. However, the complex structure of cellulose in straw makes its degradation work harder to carry out. Expansins are a class of cell wall relaxants present in plants and part of microorganisms. Moreover, expansins from microorganisms were confirmed to increase the hydrolysis efficiency of cellulase. In order to explore the synergistic effect of plant expansins on improving the ability of cellulase to degrade cellulose, an Aspergillus niger expression vector was constructed based on winter wheat expansin protein TaEXPA8, and the Aspergillus niger engineering strain pSZHGS-TaEXPA8 was obtained using Aspergillus niger CICC2462 as the receptor. At the same time, we analyzed the promoting effect of engineered strain fermentation broth on cellulose hydrolysis. Results showed that TaEXPA8 gene was able to undergo normal transcription in engineered bacteria, and the expression of TaEXPA8 protein was detected in fermented supernatant, but at a lower level. The fermentation broth of engineered strain could significantly promote the disintegration of filter paper, and glucose content produced by the hydrolysis was improved by 21.2% compared with that of single cellulase treatment. This research provides new ideas and methods for the application of plant expansins in cellulose degradation.
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