Zhao Chi, Li Zhongkui, Li Tao, Zhang Yingjiao, Bryant Donald A, Zhao Jindong
State Key Laboratory of Protein and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing, China; Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA.
Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, PA, USA.
Cell Discov. 2015 Apr 28;1:15004. doi: 10.1038/celldisc.2015.4. eCollection 2015.
Cellulose synthase, encoded by the cesA gene, is responsible for the synthesis of cellulose in nature. We show that the cell wall of the cyanobacterium Synechococcus sp. PCC 7002 naturally contains cellulose. Cellulose occurs as a possibly laminated layer between the inner and outer membrane, as well as being an important component of the extracellular glycocalyx in this cyanobacterium. Overexpression of six genes, cmc-ccp-cesAB-cesC-cesD-bgl, from Gluconacetobacter xylinus in Synechococcus sp. PCC 7002 resulted in very high-yield production of extracellular type-I cellulose. High-level cellulose production only occurred when the native cesA gene was inactivated and when cells were grown at low salinity. This system provides a method for the production of lignin-free cellulose from sunlight and CO2 for biofuel production and other biotechnological applications.
由cesA基因编码的纤维素合酶负责自然界中纤维素的合成。我们发现,蓝藻聚球藻属(Synechococcus sp.)PCC 7002的细胞壁天然含有纤维素。纤维素以可能呈层状的形式存在于内膜和外膜之间,也是这种蓝藻细胞外糖被的重要组成部分。将来自木醋杆菌(Gluconacetobacter xylinus)的六个基因cmc-ccp-cesAB-cesC-cesD-bgl在聚球藻属(Synechococcus sp.)PCC 7002中过表达,导致细胞外I型纤维素的高产。只有当天然cesA基因失活且细胞在低盐度条件下生长时,才会出现高水平的纤维素产量。该系统提供了一种利用阳光和二氧化碳生产无木质素纤维素的方法,可用于生物燃料生产和其他生物技术应用。