Consolidated bioprocessing (CBP) has the potential to reduce ethanol production costs from lignocellulosic biomass by reducing the production cost of saccharolytic enzymes.  CBP requires a microorganism that can carry out both the enzymatic depolymerization of plant cell wall polysaccharides and the fermentation of the resulting sugars to ethanol.  One microorganism that shows great promise in developing CBP is the facultative anaerobic gram-negative bacterium Zymomonas mobilis.  Z. mobilis can achieve a higher ethanol yield than most yeasts, has been metabolically engineered to use xylose, and has been successfully used to express heterologous proteins.  We describe here, the use of Z. mobilis to heterologously express the XynA endoxylanase from Thermomyces lanuginosus.  A plasmid (pJL101) was constructed that contains a chimeric gene where the T. lanuginosus XynA exons I and II are driven by the Z. mobilis pGAP promoter, and terminated by the bacteriophage T7 terminator sequence.  Transformants of Z. mobilis, grown both aerobically and anaerobically, were demonstrated to express detectable levels of endo-xylanase activity using AZCL-xylan.  Furthermore, XynA expression in Z. mobilis has no adverse effect on cell growth rates.  While we are currently unable to visualize the XynA protein via Coomassie and silver-stained polyacrylamide gels, its detectable activity on AZCL-xylan suggests that the small amount of protein being expressed is indeed very active.  Additionally, we show that this plasmid when maintained in E. coli, expresses active XynA as detected by an AZCL-xylan zymogram.  Our preliminary work provides support that Z. mobilis may eventually function as a CBP organism.