Method for producing ethanol and solvents from lignocellulosic biomass including the recirculation of a butyl wine obtained by fermenting pentoses
First Claim
1. A process for the production of alcohols, solvents, or both starting from cellulosic or lignocellulosic biomass comprising the following steps:
- a) pretreating a cellulosic or lignocellulosic substrate by thermochemical pretreatment to produce a pretreated substrate;
b) optionally washing said pretreated substrate and adjusting the pH of said pretreated substrate;
c) hydrolyzing said pretreated, optionally washed, substrate, with cellulolytic and/or hemicellulolytic enzymes, wherein an aqueous stream comprising a hydrolysate and a water-insoluble residue is produced;
d) fermenting hexoses contained in said hydrolysate obtained from step c) in the presence of an alcohologenic microorganism of the genus Saccharomyces to produce an ethyl wine comprising ethanol and solvents;
e) extracting said ethyl wine of step d), said extracting comprisinge1) separating and purifying ethanol and/or solvents obtained from step d), ande2) separating a solid cake containing said water-insoluble residue to produce vinasses;
f) fermenting pentoses contained in said vinasses obtained from step e2) in the presence of a solventogenic microorganism of the genus Clostridium to produce a butyl wine, wherein said butyl wine comprises a mixture of solvents comprising acetone, butanol, and ethanol, or comprises a mixture of solvents comprising isopropanol, butanol, and ethanol;
g) recycling at least a portion of said butyl wine upstream from at least one of step c) and/or step d), wherein after said recycling of at least a portion of said butyl wine said aqueous stream in step c) contains between 0.1 and 20 g/L of solvents, and a butanol portion of said solvents is present in a concentration of between 0.1 and 15 g/L.
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Abstract
This invention describes a process for the production of second generation alcohols and/or solvents starting from cellulosic or lignocellulosic biomass wherein the lignocellulosic or cellulosic biomass undergoes a pretreatment before being converted into ethanol after an enzymatic hydrolysis and an ethylic fermentation, wherein glucidic polymers of the pretreated plant are hydrolyzed by cellulases; microorganisms that primarily use hexoses and preferably glucose and mannose are used for the ethylic fermentation; wines, with or without separation of materials in suspension are extracted by distillation; pentoses in the vinasses are fermented by a solventogenic microorganism into a butyl wine, and at least one portion of the butyl wine is recycled upstream from enzymatic hydrolysis.
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Citations
8 Claims
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1. A process for the production of alcohols, solvents, or both starting from cellulosic or lignocellulosic biomass comprising the following steps:
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a) pretreating a cellulosic or lignocellulosic substrate by thermochemical pretreatment to produce a pretreated substrate; b) optionally washing said pretreated substrate and adjusting the pH of said pretreated substrate; c) hydrolyzing said pretreated, optionally washed, substrate, with cellulolytic and/or hemicellulolytic enzymes, wherein an aqueous stream comprising a hydrolysate and a water-insoluble residue is produced; d) fermenting hexoses contained in said hydrolysate obtained from step c) in the presence of an alcohologenic microorganism of the genus Saccharomyces to produce an ethyl wine comprising ethanol and solvents; e) extracting said ethyl wine of step d), said extracting comprising e1) separating and purifying ethanol and/or solvents obtained from step d), and e2) separating a solid cake containing said water-insoluble residue to produce vinasses; f) fermenting pentoses contained in said vinasses obtained from step e2) in the presence of a solventogenic microorganism of the genus Clostridium to produce a butyl wine, wherein said butyl wine comprises a mixture of solvents comprising acetone, butanol, and ethanol, or comprises a mixture of solvents comprising isopropanol, butanol, and ethanol; g) recycling at least a portion of said butyl wine upstream from at least one of step c) and/or step d), wherein after said recycling of at least a portion of said butyl wine said aqueous stream in step c) contains between 0.1 and 20 g/L of solvents, and a butanol portion of said solvents is present in a concentration of between 0.1 and 15 g/L. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification