Feasibility test of utilizing Saccharophagus degradans 2-40 T as the source of crude enzyme for the saccharification of lignocellulose

In the conversion of lignocellulose into high- value products, including fuels and chemicals, the produc- tion of cellulase and the enzymatic hydrolysis for producing fermentable sugar are the largest contributors to the cost of production of the final products. The marine bacterium Saccharophagus degradans 2-40 T can degrade more than ten different complex polysaccharides found in the ocean, including cellulose and xylan. Accordingly, S. degradans has been actively considered as a practical source of crude enzymes needed for the saccharification of lignocellulose to produce ethanol by others including a leading commercial company. However, the overall enzyme system of S. de- gradans for hydrolyzing cellulose and hemicellulose has not been quantitatively evaluated yet in comparison with commercial enzymes. In this study, the inductions and activities of cellulase and xylanase of cell-free lysate of S. degradans were investigated. The growth of S. degradans cells and the activities of cellulase and xylanase were pro- moted by adding 2 % of cellulose and xylan mixture (cel- lulose:xylan = 4:3 in mass ratio) to the aquarium salt medium supplemented with 0.2 % glucose. The specific cellulase activity of the cell-free lysate of S. degradans ,a s determined by the filter paper activity assay, was approxi- mately 70 times lower than those of commercial cellulases, including Celluclast 1.5 L and Accellerase 1000. These results imply that significant improvement in the cellulase activity of S. degradans is needed for the industrial uses of S. degradans as the enzyme source.