Process for the manufacture of butanol or acetone

Abstract

A process for the manufacture of butanol, acetone and/or other renewable chemicals is provided wherein the process utilises one or more of the group comprising by-products of the manufacture of malt whisky, such as pot ale and/or spent lees, biomass substrates, such as paper, sludge from paper manufacture and spent grains from distillers and brewers, and diluents, such as water and spent liquid from other fermentations. The process comprises treating a substrate to hydrolyse it and fermenting the treated. Also provided is a biofuel comprising butanol manufactured according to the process of the invention.

1 . A process for the manufacture of butanol and/or acetone, comprising at least the steps of:
 treating a substrate comprising a carbohydrate source and pot ale to solubilise at least a portion of the carbohydrate source to provide a treated substrate; and   fermenting the treated substrate in the presence of a culture of butanol- and/or acetone-forming micro-organisms at a concentration of free copper ions of less than 20 μM to provide a fermented product containing butanol and/or acetone.   
     
     
         2 . The process as claimed in  claim 1  wherein the step of treating the substrate comprises:
 hydrolysing the carbohydrate source in the presence of water and hydrogen ions or water and hydroxide ions. 
 
     
     
         3 . The process as claimed  claim 1  wherein the step of treating the substrate comprises:
 hydrolysing the carbohydrate source in the presence of an aqueous solution of sulphuric acid. 
 
     
     
         4 . The process as claimed in  claim 1  wherein the step of treating of the substrate comprises:
 treating the carbohydrate source with one or more enzymes. 
 
     
     
         5 . The process as claimed in  claim 1  wherein the step of treating the substrate further comprises:
 diluting the substrate to provide a concentration of free copper ions of less than 20 μm. 
 
     
     
         6 . The process as claimed in  claim 1  wherein the step of fermenting the treated substrate is carried out at a pH of 5.1 or above. 
     
     
         7 . The process as claimed in  claim 1  wherein the concentration of free copper ions in the fermentation step is less than 15 μM. 
     
     
         8 . The process as claimed in  claim 1  wherein the culture of butanol- and/or acetone-forming micro-organisms comprises bacteria of the genus  Clostridium.    
     
     
         9 . The process as claimed in  claim 1  wherein the fermentation step is carried out without the removal of solids therefrom. 
     
     
         10 . The process as claimed in  claim 1  in which the treating and fermenting steps are carried out simultaneously. 
     
     
         11 . The process as claimed in  claim 1  in which the treating and fermenting steps are carried out sequentially. 
     
     
         12 . The process as claimed in  claim 1  wherein the pot ale is provided by the steps of:
 adding yeast to a wort comprising water and one or more carbohydrates selected from the group comprising glucose and oligosaccharides of glucose; 
 fermenting the wort to provide a wash comprising water and one or more alcohols; and 
 distilling the wash in a copper distillation vessel to provide a low wines distillate comprising one or more alcohols and a distillation residue of pot ale. 
 
     
     
         13 . The process as claimed in  claim 12  wherein the wort is provided by the further steps of:
 grinding malted barley comprising starch to provide ground malted barley; 
 mixing the ground malted barley with water to provide a mash comprising water and ground malted barley; 
 hydrolysing at least a part of the starch in the ground malted barley of the mash to provide draff comprising spent barley solids and wort comprising water and one or more carbohydrates selected from the group comprising glucose and oligosaccharides of glucose; and 
 separating the draff from the wort. 
 
     
     
         14 . The process as claimed in  claim 1  wherein the pot ale is the by-product of the manufacture of malt whisky, preferably Scotch malt whisky. 
     
     
         15 . The process as claimed in  claim 1  wherein the carbohydrate source is selected from one or more of the group comprising paper, sludge from paper manufacture, fruit and vegetable waste, waste from the baking industry, seaweed and seaweed extracts, forestry derivatives, food crops, grain and crop residues, spent grains, chocolate, algae, non-edible crops and their residues and energy crops. 
     
     
         16 . The process as claimed in  claim 1  wherein the fermented product further comprises one or more of the compounds selected from the group comprising ethanol, carbon dioxide, hydrogen, acetate and butyrate. 
     
     
         17 . A biofuel comprising butanol manufactured according to the process of  claim 1 . 
     
     
         18 . A product comprising butanol and/or acetone manufactured according to the process of  claim 1 . 
     
     
         19 . (canceled)