Processing biomass
Biomass (e.g., plant biomass, animal biomass, and municipal waste biomass) is processed to produce useful intermediates and products, such as energy, fuels, foods or materials. For example, methods are described that can use feedstock materials, such as cellulosic and/or lignocellulosic materials, to produce an intermediate or product, e.g., by fermentation.
1. A method of producing a product or intermediate from a cellulosic or lignocellulosic material, the method comprising
combining a feedstock, comprising a cellulosic or lignocellulosic material and/or a saccharified cellulosic or lignocellulosic material, with a microorganism and a food-based nutrient source that is not derived from the feedstock to form a mixture, the microorganism utilizing the feedstock to produce the product or the intermediate,
wherein the mixture comprises a medium and the concentration of the food-based nutrient source in the medium is from 0.1 to 80 g/L, and
wherein the mixture further comprises an enzyme system comprising one or more enzymes selected from the group consisting of amylases, proteases, and mixtures thereof.
2. The method of claim 1 wherein the food-based nutrient source is selected from the group consisting of grains, vegetables, residues of grains, residues of vegetables, residues of meat products, and mixtures thereof.
3. The method of claim 1 wherein the product comprises a fuel selected from the group consisting of hydrogen, alcohols, organic acids, hydrocarbons, and mixtures thereof.
4. The method of claim 1 wherein utilizing comprises fermentation.
5. The method of claim 4 wherein the microorganism is a yeast.
6. The method of claim 4 wherein fermentation is conducted at a pH of about 4.8 to 5.2.
7. The method of claim 1 wherein utilizing comprises saccharification.
8. The method of claim 7 wherein the microorganism comprises an enzyme selected to saccharify the feedstock.
9. The method of claim 8 wherein the enzyme is a hemicellulase or a cellulase.
10. The method of claim 7 wherein saccharification is conducted at a pH of about 3.8 to 4.2.
11. The method of claim 1 wherein the mixture further comprises a nitrogen source.
12. The method of claim 11 wherein the nitrogen source is selected from the group consisting of urea, ammonia, ammonium sulfate, and mixtures thereof.
13. The method of claim 1 wherein the food-based nutrient source is selected from the group consisting of wheat, oats, barley, soybeans, peas, legumes, potatoes, corn, rice bran, corn meal, wheat bran, and mixtures thereof.
14. The method of claim 1 wherein the enzyme system comprises a protease and an amylase.
15. The method of claim 14 wherein the mixture further comprises a hemicellulase or a cellulase.
16. The method of claim 1 wherein the concentration of the food-based nutrient source in the medium is from about 0.1 to 10 g/L.
17. The method of claim 3 , wherein the alcohol is selected from the group consisting of methanol, ethanol, propanol, isopropanol, n-butanol, ethylene glycol, propylene glycol, 1,4-butane diol, glycerin, and mixtures thereof.
18. The method of claim 3 , wherein the organic acid is selected from the group consisting of formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, palmitic acid, stearic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, oleic acid, linoleic acid, glycolic acid, lactic acid, γ-hydroxybutyric acid and mixtures thereof.
19. The method of claim 3 , wherein the hydrocarbon is selected from the group consisting of methane, ethane, propane, isobutene, pentane, n-hexane, and mixtures thereof.
20. The method of claim 1 wherein the cellulosic or lignocellulosic material has been treated to reduce its recalcitrance.
21. The method of claim 20 wherein the cellulosic or lignocellulosic material has been treated with radiation.
22. The method of claim 21 wherein the radiation is by an electron beam.