Evaluation of Cellulase Production by Zymomonas mobilis

Abstract

Z. mobilis has been widely studied as a potential microbe for consolidated bioprocessing to convert lignocellulosic biomass to fermentable sugars while at the same time producing ethanol. To achieve this goal, Z. mobilis must be evaluated for the production of cellulolytic enzyme. This work reports on the potential of intracellular and extracellular crude extracts from Z. mobilis ZM4 and TISTR 551 to hydrolyze various cellulosic materials including carboxymethylcellulose (CMC), delignified rice bran, microcrystalline cellulose, and filter paper. Crude intracellular extracts from ZM4 and TISTR 551 showed high endoglucanase activity with CMC substrates at an optimal pH of 6 to 7 and temperature range of 30 to 40 °C. The endoglucanase activity from the crude extracts was significantly higher than the exoglucanase activity. Of the high crystalline celluloses substrates tested, the best results were obtained for the hydrolysis of delignified rice bran by crude intracellular enzyme extracts of Z. mobilis TISTR 551.

Keywords

• Consolidated bioprocess; Zymomonas mobilis; Cellulase; Lignocellulosic material