基于DNA-稳定同位素探针的纤维素分解菌群的宏基因组学研究

秸秆生物炼制可有效地缓解能源危机，而纤维素酶的低催化活性限制了其工业化应用。宏基因组学技术的发展为高活性纤维素酶的开发提供了新思路，却普遍存在筛选效率低下的局限。针对这一问题，本项目拟将DNA-稳定同位素探针技术(DNA-SIP)引入到传统的宏基因组学中，以提高新型纤维素酶的发现概率。采用微生物合成高质量的13C-纤维素，并作为标记底物对环境样品进行功能微生物的富集；同时应用分子指纹技术鉴定参与13C-纤维素分解的微生物菌群及功能基因多样性，揭示其生理代谢机制；在此基础上，结合不同筛选策略获取13C-宏基因组DNA中的新型纤维素酶，并对其实现高效异源表达。本研究旨在为纤维素生物炼制提供高效的纤维素酶催化剂，进而加速秸秆资源化的工业化进程。

Straw biorefinery can effectively relieve energy crisis. However, the low activity of cellulase is the major neckbottle which limits the industrialization of straw biorefinery. Metagenomic technology provides a new way for discovering high-activity cellulases, but it has the limitation of low sceening efficiency. In this project, it is attempted to combine DNA stable-isotope probing (DNA-SIP) and metagenomics for improving the hit rate of discovering novel cellulases. The main contents are described as follows: first, producing high-quality 13C-cellulose by active microbes, and which is then used as the substrate for the microbes enrichment in environmental samples; Meanwhile, analyzing the diversities of microbial community and functional genes for cellulose degradation by molecular fingerprint technologies. Then, screening novel cellulases from 13C-metagenomic DNA using different strategies, and realizing the heterologous expression of metagenome-derived cellulases. This study will provide effective enzyme catalysts for cellulose biorefinery and accelerate the development of straw utilization.