Process for alcoholic fermentation of lignocellulosic biomass

Abstract

A process for the production of ethanol wherein a hydrolyzed lignocellulosic biomass is fermented in the presence of a stillage residue. The fermentation of cellulosic hydrolysates is improved by adding prior to and/or during fermentation a stillage residue side stream from a corn starch-to-ethanol process as a nutrient source for the yeast organisms used in the fermentation. Stillage residues from the grain dry mill ethanol producing process, including the whole stillage, wet cake, thin stillage, and/or syrup are added to assist as a nitrogen and nutrient source for the fermentive processes. The stillage residue is produced by any grain-to-ethanol process.

What is claimed is: 
     
         1 . A process for the production of ethanol, the process comprising the step of fermenting a hydrolyzed lignocellulosic biomass in the presence of a stillage residue, the stillage residue is produced by a whole grain starch-to-ethanol process. 
     
     
         2 . The process of  claim 1 , wherein the stillage residue is selected from the group consisting of whole stillage, thin stillage, wetcake, syrup, and any combination thereof. 
     
     
         3 . The process of  claim 1 , further comprising a propagation step whereby yeast is conditioned and grown prior to the step of fermentation. 
     
     
         4 . The process of  claim 1 , wherein the hydrolyzed lignocellulosic biomass is produced by acid pre-treatment wherein the acid catalyst is a mineral acid or a carboxylic acid. 
     
     
         5 . The process of  claim 1 , wherein the hydrolyzed lignocellulosic biomass is selected from the group consisting of agricultural residues, purpose grown crops, woody biomass, and any combination thereof. 
     
     
         6 . The process of  claim 1 , wherein the hydrolyzed lignocellulosic biomass is obtained from corn cobs. 
     
     
         7 . The process of  claim 1 , wherein the ethanol is produced by fermentation with a ethanologenic organism. 
     
     
         8 . The process of  claim 7 , wherein the ethanologenic organism is a prokaryotic organism. 
     
     
         9 . The process of  claim 8 , wherein the ethanologenic organism is selected from the group consisting of  Escherichia coli, Klebsiella oxytoca,  and  Zymomonas mobilis, Clostridium thermocellum.    
     
     
         10 . The process of  claim 7 , wherein the ethanologenic organism is a eukaryotic organism. 
     
     
         11 . The process of  claim 10 , wherein the eukaryotic organism is selected from the group consisting of  Saccharomyces cerevisia, Pichia stipitis.    
     
     
         12 . A process for the propagation of yeast, the process comprising the step of propagating yeast in the presence of a stillage residue from a whole grain starch-to-ethanol process. 
     
     
         13 . The process of  claim 12 , wherein the stillage residue is selected from the group consisting of whole stillage, thin stillage, wetcake, syrup, and any combination thereof.