The sequence of the putative endoglucanase gene ZMO1086 in the genome of Zymomonas mobilis showed a 40% similarity with known bacterial endoglucanase genes. The upstream region of this putative gene revealed the presence of characteristic promoter (-10 and -35 regions) and a Shine-Dalgarno region. The putative endoglucanase gene was poorly expressed from the native promoter of Z. mobilis and therefore the putative endoglucanase gene was cloned and expressed in Escherichia coli BL21. The overexpressed gene product CelA was purified to homogeneity and the optimal activity was observed at 30 degrees C and pH 6 respectively.