Lower cellulase requirements for biomass cellulose hydrolysis and fermentation
First Claim
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1. A method for producing ethanol from a cellulosic substrate, comprising the steps of:
- (a) roviding within a reaction vessel, a reaction mixture in the form of a slurry comprising cellulosic substrate, an enzyme and a fermentation agent, wherein the reaction mixture is reacted under conditions sufficient to initiate and maintain a fermentation reaction;
(b) etermining, by experiment or theoretical calculations, an optimum feeding frequency; and
(c) roviding additional quantities of the cellulosic substrate and the enzyme into the reaction vessel at an interval(s) according to the optimized feeding frequency.
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Abstract
A semi-continuous simultaneous saccharification and fermentation (SSF) process for the bioconversion of cellulose into ethanol and other organic chemicals is disclosed. The process provides for substantially higher substrate conversion at a given enzyme loading (or alternatively a lower enzyme loading used to achieve the same conversion) in a reactor operated according to a semi-continuous feeding protocol.
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18 Claims
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1. A method for producing ethanol from a cellulosic substrate, comprising the steps of:
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(a) roviding within a reaction vessel, a reaction mixture in the form of a slurry comprising cellulosic substrate, an enzyme and a fermentation agent, wherein the reaction mixture is reacted under conditions sufficient to initiate and maintain a fermentation reaction;
(b) etermining, by experiment or theoretical calculations, an optimum feeding frequency; and
(c) roviding additional quantities of the cellulosic substrate and the enzyme into the reaction vessel at an interval(s) according to the optimized feeding frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of operating a reactor system to provide semi-continuous solids-fed fermentation of paper sludge, comprising:
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advancing a paper sludge under a semi-continuous controlled flow rate;
chopping the paper sludge as it advances to subdivide the paper sludge into comparatively smaller particles;
digesting the comparatively smaller particles in an agitator by the action of a hydrolyzing enzyme; and
controlling the flow rate and amount of hydrolyzing enzyme added to the agitator for use in the step of digesting to establish a semi-continuous state of flow through the reactor system over an extended period of time while also maintaining a predetermined conversion efficiency of the paper sludge by action of the hydrolyzing enzyme at an optimized loading concentration. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A semi-continuous solids-fed bioreactor comprising:
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a feed tube containing a plug of solid waste;
a screw driven by a timer-controlled motor, the screw acting to advance the plug of solid waste into a chopper; and
an agitator that receives solid waste particles from the chopper and enzymes, fermentation agents and liquid reagents from an inlet valve, the solid waste particles, enzymes, fermenation agents and liquid reagents forming a slurry in the agitator, wherein the agitator includes a mixer driven by a second motor and at least one conduit from which products may be removed. - View Dependent Claims (17, 18)
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Specification