Systems and methods for producing biofuels and related materials

Abstract

Clostridium phytofermentans cells (American Type Culture Collection 700394 T ) and all other strains of the species can ferment materials such as biomass into useful products and coproducts, such as ethanol, hydrogen and organic acids. Compositions that include Clostridium phytofermentans are also disclosed.

1 . A method of making a fuel from biomass material, the method comprising:
 providing a biomass material comprising a high molecular weight carbohydrate;   hydrolyzing the biomass material to provide a hydrolyzed biomass material;   combining the hydrolyzed biomass material with  Clostridium phytofermentans  cells in a medium, wherein a concentration of carbohydrates in the medium is greater than 20 mM; and   fermenting the hydrolyzed biomass material under conditions and for a time sufficient to produce a fuel.   
   
   
       2 . The method of  claim 1 , wherein the fuel comprises an alcohol selected from the group consisting of ethanol, n-propanol, isopropanol, n-butanol, and mixtures thereof. 
   
   
       3 . The method of  claim 1 , wherein the biomass material is hydrolyzed by treatment with an acid. 
   
   
       4 . The method of  claim 1 , wherein the biomass material is hydrolyzed by treatment with an enzyme or a mixture of enzymes. 
   
   
       5 . The method of  claim 1 , wherein the biomass material is hydrolyzed by treatment with an acid, followed by treatment with an enzyme. 
   
   
       6 . The method of  claim 1 , wherein the biomass material is reduced in size prior to hydrolyzing. 
   
   
       7 . The method of  claim 1 , wherein the hydrolysis step includes pretreatment with acid in an acidification unit, followed by de-watering. 
   
   
       8 . A fuel plant comprising:
 a hydrolysis unit configured to hydrolyze a biomass material comprising a high molecular weight carbohydrate; and   a fermentor configured to house a medium and comprising  Clostridium  phytofermentans cells dispersed therein.   
   
   
       9 . The fuel plant of  claim 8 , wherein the fermentor configured to house the medium and comprising  Clostridium phytofermentans  further comprises one or more other microbes different than  Clostridium phytofermentans.    
   
   
       10 . The fuel plant of  claim 9 , wherein the one or more other microbes comprise one or more yeasts. 
   
   
       11 . The fuel plant of  claim 9 , wherein the one or more other microbes comprise one or more bacteria. 
   
   
       12 . The fuel plant of  claim 11 , wherein the one or more bacteria comprise any one or more stains of  Zymomonas mobilis.    
   
   
       13 . A method of making a fuel, the method comprising:
 combining  Clostridium phytofermentans  cells and a lignocellulosic material in a medium; and   fermenting the lignocellulosic material under conditions and for a time sufficient to produce a fuel.   
   
   
       14 . The method of  claim 13 , wherein the lignocellulosic material is selected from the group consisting of wood, wood pulp, papermaking sludge, paper pulp waste streams, particle board, grasses, rice hulls, bagasse, cotton, jute, hemp, flax, bamboo, sisal, abaca, straw, corn cobs, corn stover, distillers grains, leaves, wheat straw, coconut hair, algae, switchgrass, Miscanthus, legume plants, sorghum, biomass crops (Crambe), and mixtures thereof. 
   
   
       15 . The method of  claim 13 , wherein the medium has dissolved therein constituents selected from the group consisting of growth factors, minerals, surfactants, chelating agents, and mixtures thereof. 
   
   
       16 . The method of  claim 13 , wherein conditions include maintaining the medium at a temperature of less than about 45° C. 
   
   
       17 . The method of  claim 13 , wherein conditions include maintaining a pH of the medium below about 9.5. 
   
   
       18 . The method of  claim 13 , wherein the fuel is ethanol, and wherein conditions include maintaining a concentration of the ethanol lower than about 1 M. 
   
   
       19 . A method of making a fuel, the method comprising:
 combining  Clostridium phytofermentans  cells and a material comprising a carbohydrate in a medium, wherein a concentration of the carbohydrate in the medium is greater than 40 mM; and   fermenting the material comprising the carbohydrate under conditions and for a time sufficient to produce a fuel.   
   
   
       20 . The method of  claim 19 , wherein the concentration is greater than 50 mM. 
   
   
       21 . The method of  claim 20 , wherein the concentration is greater than 100 mM. 
   
   
       22 . The method of  claim 21 , wherein the concentration is less than 2000 mM. 
   
   
       23 . The method of  claim 19 , wherein the material comprises a low molecular weight carbohydrate having a molecular weight of less than 1,000. 
   
   
       24 . The method of  claim 23 , wherein the low molecular weight carbohydrate is selected from the group consisting of arabinose, cellobiose, fructose, galactose, glucose, lactose, mannose, ribose, xylose, and mixtures thereof. 
   
   
       25 . The method of  claim 19 , wherein the material comprises a high molecular weight carbohydrate having a molecular weight of greater than 1,000. 
   
   
       26 . The method of  claim 25 , wherein the high molecular weight carbohydrate is selected from the group consisting of cellulose, microcrystalline cellulose, polygalacturonic acid, pectin, starch, xylan, and mixtures thereof. 
   
   
       27 . The method of  claim 19 , wherein the material is pulverized such that it has a particle size of between about 5 microns and 50 microns. 
   
   
       28 . The method of  claim 19 , wherein the material comprises a blend of two or more carbohydrates. 
   
   
       29 . The method of  claim 19 , wherein the material comprises a cellulosic or lignocellulosic material. 
   
   
       30 . The method of  claim 29 , wherein the cellulosic or lignocellulosic material is selected from the group consisting of polycoated paper, Kraft paper, papermaking sludge, wood, wood pulp, distillers grains, particle board, leaves, grasses, grass clippings, rice hulls, bagasse, cotton, jute, hemp, flax, bamboo, sisal, abaca, straw, corn cobs, corn stover, wheat straw, coconut hair, algae, switchgrass,  crambe , biomass crops, and mixtures thereof. 
   
   
       31 . The method of  claim 19 , wherein the material comprises a low molecular weight carbohydrate formed by breaking down a high molecular weight carbohydrate. 
   
   
       32 . The method of  claim 31 , wherein the breaking down includes using an enzyme. 
   
   
       33 . The method of  claim 32 , wherein the enzyme is selected from the group consisting of endoglucanases, exoglucanases, cellobiohydrolases (CBH), β-glucosidase, glycoside hydrolases, glycosyltransferases, lyases, and esterases active against components of hemicellulose, pectin, and starch, and mixtures thereof. 
   
   
       34 . The method of  claim 19 , wherein the material is substantially free of lignin. 
   
   
       35 . A method comprising:
 combining  Clostridium phytofermentans  cells, a second microbe and a material comprising a carbohydrate in a medium; and   fermenting the material comprising the carbohydrate.   
   
   
       36 . The method of  claim 35 , wherein the fermenting is carried out under conditions and for a time sufficient to produce a fuel. 
   
   
       37 . The method of  claim 35 , wherein the second microbe comprises a yeast. 
   
   
       38 . The method of  claim 35 , wherein the second microbe comprises a bacterium different than  Clostridium phytofermentans.    
   
   
       39 . A composition comprising  Clostridium phytofermentans  and a second microbe.