Processing biomass

Abstract

Biomass (e.g., plant biomass, animal biomass, and municipal waste biomass) is processed for use in the production of useful products, such as fuels. For example, systems can use biomass materials, such as cellulosic and/or lignocellulosic materials, to enhance the production of a product, e.g., the production of ethanol and/or butanol by fermentation.

1 . A method for fermenting a low molecular weight sugar to a product comprising:
 contacting a low molecular weight sugar, in a medium, with a functionalized biomass and a fermenting microorganism immobilized on the biomass by ionic bonding of complementary charged groups on the functionalized biomass and the microorganism; and   fermenting the low molecular weight sugar under conditions suitable for converting said sugar to a product by the fermenting microorganism;   wherein the biomass fibers have been functionalized by exposure to a particle beam accelerator.   
     
     
         2 . The method of  claim 1  wherein fermenting converts at least a portion of the low molecular weight sugar to a hydrocarbon, an alcohol, or hydrogen. 
     
     
         3 . The method of  claim 2  wherein the alcohol is ethanol. 
     
     
         4 . The method of  claim 1  wherein the microorganism is a yeast. 
     
     
         5 . The method of  claim 4  wherein the yeast is selected from the group consisting of  S. cerevisiae  and  P. stipitis.    
     
     
         6 . The method of  claim 1  wherein the microorganism is a bacterium. 
     
     
         7 . The method of  claim 6  wherein the bacterium comprises  Zymomonas mobilis.    
     
     
         8 . The method of  claim 1  wherein the biomass has been irradiated in an oxidizing environment. 
     
     
         9 . The method of  claim 8  wherein irradiating is performed using an electron beam. 
     
     
         10 . The method of  claim 1  wherein the biomass comprises a cellulosic or lignocellulosic material. 
     
     
         11 . The method of  claim 1  wherein the biomass comprises fibers having a BET surface area of greater than 0.25 m2/g. 
     
     
         12 . The method of  claim 1 , wherein the biomass is selected from the group consisting of paper, paper products, paper waste, wood, particle board, sawdust, agricultural waste, sewage, silage, grasses, rice hulls, bagasse, jute, hemp, flax, bamboo, sisal, abaca, straw, corn cobs, corn stover, switchgrass, alfalfa, hay, coconut hair, cotton, seaweed, algae, and mixtures thereof. 
     
     
         13 . The method of  claim 11  wherein the biomass fibers are derived from a biomass feedstock that has internal fibers, and that has been sheared to an extent that its internal fibers are substantially exposed. 
     
     
         14 . The method of  claim 11  wherein the biomass fibers have a porosity greater than 70%. 
     
     
         15 . The method of  claim 1  further comprising recovering the biomass after fermenting and reusing the biomass in a second, subsequent fermentation process. 
     
     
         16 . The method of  claim 1  wherein the biomass is in the form of a sheet. 
     
     
         17 . The method of  claim 17  wherein the sheet is overlaid, folded, or in the form of a screen or mesh. 
     
     
         18 . The method of  claim 1  wherein the biomass comprises fibers that are extruded or coextruded. 
     
     
         19 . The method of  claim 1  wherein the biomass comprises fibers having a nano-scale average particle size. 
     
     
         20 . The method of  claim 1  wherein functionalizing comprises exposing the biomass to 5 to 60 Mrad of radiation.