NOVELTY - A catalytic membrane comprises a surface functionalized with a polymer comprising cellulose solubilization functionalities and acid functionalities for the catalytic hydrolysis of cellulose.    USE - The catalytic membrane is useful for hydrolysis of cellulose (claimed) and/or hemicellulose, generally for biomass hydrolysis.    ADVANTAGE - The catalytic membrane is stable in an environment having a pH of less than about 5, pH of less than about 3 or less than about 2, or pH of between about 1 and about 5. It is stable at a temperature of at least about 100 degrees C, up to about 200 degrees C or up to about 300 degrees C, or from about 0 degrees C to about 200 degrees C or from about 0 degrees C to about 300 degrees C. The catalytic membrane does not demonstrate any significant chemical and/or physical degradation including, but not limited to, the loss of surface functionalizing polymer, erosion of the membrane surface and loss of pore structure due to plastic deformation or membrane dissolution. The catalytic membranes have sufficient mechanical strength to withstand pressurizing and/or back flushing. Additionally, the catalytic membrane can be subjected to the application of pressure on the retentate side of the membrane to assist in driving cellulose hydrolysis product(s) across the membrane.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are:    (1) a membrane reactor comprising a feedstock vessel; a reaction product collection vessel; and a catalytic membrane disposed between the feedstock vessel and the reaction product collection vessel, the membrane comprising a feedstock contacting surface functionalized with a polymer, the polymer comprising cellulose solubilization functionalities and acid functionalities for the catalytic hydrolysis of cellulose;    (2) a method for hydrolysis of cellulose comprising providing a cellulose feedstock; bringing the cellulose feedstock into contact with a surface of a catalytic membrane, the surface functionalized with a polymer comprising cellulose solubilization functionalities and acid functionalities for the catalytic hydrolysis of the cellulose; at least partially solubilizing the cellulose with the cellulose solubilization functionalities; and hydrolyzing the solubilized cellulose with the acid functionalities to provide glucose, reducing sugars or oligosaccharides or its mixtures; and    (3) a method of making a catalytic membrane comprising grafting onto a surface of the membrane a polymer comprising cellulose solubilization functionalities and acid functionalities for the catalytic hydrolysis of cellulose.