초록
<P>Cellulose synthase, encoded by the <I>cesA</I> gene, is responsible for the synthesis of cellulose in nature. We show that the cell wall of the cyanobacterium <I>Synechococcus</I> 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, <I>cmc–ccp–cesAB–cesC–cesD–bgl,</I> from <I>Gluconacetobacter xylinus</I> in <I>Synechococcus</I> sp. PCC 7002 resulted in very high-yield production of extracellular type-I cellulose. High-level cellulose production only occurred when the native <I>cesA</I> 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 CO<SUB>2</SUB> for biofuel production and other biotechnological applications.</P>