Reducing the cost of cellulase enzyme production is a key issue in the enzymatic hydrolysis of lignocellulosic materials. Genetic techniques have been used to clone the cellulase coding sequences into bacteria, yeasts, fungi, and plants to create new cellulase production systems with possible improvement of enzyme production and activity. Riley et al. (1996) and Wood et al. (1997) reported the expression of recombinant endoglucanase genes from Erwinia chrysanthemi P86021 in E. coli KO11, and the recombinant system produced 3,200 IU endoglucanase/l fermentation broth (IU, international unit, defined as a micromole of reducing sugar as glucose released per minute using carboxymethyl cellulose as substrate). The thermostable endoglucanase E1 from Acidothermus cellulolyticus was expressed in Arabidopsis thaliana leaves (Ziegler et al. 2000), potato (Dai et al. 2000), and tobacco
(Hooker et al. 2001).