Ethanol production with an immobilized cell reactor

Claim 1

A process for producing ethanol from cellulosic material containing pentosans and hexosans comprising treating the cellulosic material in a first hydrolysis stage with a dilute acid solution to hydrolyze the pentosans to xylose without substantial hydrolysis of hexosans to glucose, separating solids from the resultant hydrolyzate, treating the solids in a second hydrolysis stage with a concentrated acid solution to hydrolyze the hexosans to glucose, and fermenting the glucose to ethanol by passing a solution of the glucose over a fixed film of yeast organisms which ferment said glucose to ethanol, said film of organisms being prepared by coating a solid support with proteinaceous material having free amino groups, treating the proteinaceous material with a polyfunctional agent which is capable of reacting with free amino groups and inoculating the treated proteinaceous material with an inoculum of the yeast organisms, said yeast organisms having free amino groups and said polyfunctional agent reacting with free amino groups contained by the proteinaceous material and the yeast organisms said inoculum being added from solution before the reaction between the polyfunctional agent and the proteinaceous material has substantially gone to completion whereby the yeast organisms are attached to the proteinaceous coat by the polyfunctional agent such that a substantial number of bonds are formed between the yeast and the proteinaceous coat.