Methods to enhance the activity of lignocellulose-degrading enzymes

Abstract

Methods for hydrolyzing lignocellulose are provided, comprising contacting the lignocellulose with at least one chemical treatment. Methods for pretreating a lignocellulosic material comprising contacting the material with at least one chemical are also provided. Methods for liberating a substance such as an enzyme, a pharmaceutical, or a nutraceutical from plant material are also provided. These methods are more efficient, more economical, and less toxic than current methods.

Description

[0001] The present application claims the benefit of U.S. Provisional Application Serial No. 60 / 452,631, filed Mar. 7, 2003, U.S. Provisional Application No. 60 / 498,098, filed Aug. 27, 2003, U.S. Provisional Application No. 60 / 502,727, filed Sep. 12, 2003, and U.S. Provisional Application No. 60 / 538,334, filed Jan. 22, 2004, the contents of which are herein incorporated by reference in their entirety.[0002] Methods to enhance the production of free sugars and oligosaccharides from plant material are provided.[0003] Plant biomass is comprised of sugars and represents the greatest source of renewable hydrocarbon on earth. However, this enormous resource is under-utilized because the sugars are locked in complex polymers. These complex polymers are often referred to collectively as lignocellulose. Sugars generated from degradation of plant biomass could provide plentiful, economically competitive feedstocks for fermentation into chemicals, plastics, and fuels, including ethanol as a su...

AI Technical Summary

Benefits of technology

[0018] FIG. 2 shows reducing sugar content released from corn stover (measured by DNS assay) following treatment with various concentrations of hydrogen peroxide alone or in combination with enzymatic treatment.

[0033] By "detergent" is intended a compound that can form micelles to sequester oils. Detergents include anionic, cationic, or neutral detergents, including, but not limited to, Nonidet (N) P-40, sodium dodecyl sulfate (SDS), sulfobetaine, n-octylglucoside, deoxycholate, Triton X-100, and Tween 20. Included in the definition are surfactants. By "surfactant" is intended a compound that can lower the surface tension of water.

[0040] The methods of the invention improve the efficiency of biomass conversion to simple sugars and oligosaccharides. Efficient biomass conversion will reduce the costs of sugars that can then be converted to useful fermentation based products. By "fermentation-based product" is intended a product produced by chemical conversion or fermentation. Such products include, but are not limited to, specialty chemicals, chemical feedstocks, plastics, solvents and fuels. Specific products that may be produced by the methods of the invention include, but not limited to, biofuels (including ethanol); lactic acid; plastics; specialty chemicals; organic acids, including citric acid, succinic acid and maleic acid; solvents; animal feed supplements; pharmaceuticals; vitamins; amino acids, such as lysine, methionine, tryptophan, threonine, and aspartic acid; industrial enzymes, such as proteases, cellulases, amylases, glucanases, lactases, lipases, lyases, oxidoreductases, and transferases; and chemical feedstocks. The methods of the invention are also useful to generate feedstocks for fermentation by fermenting microorganisms. In one embodiment, the method further comprises the addition of at least one fermenting organism. By "fermenting organism" is intended an organism capable of fermentation, such as bacteria and fungi, including yeast. Such feedstocks have additional nutritive value above the nutritive value provided by the liberated sugars.

[0041] The methods of the invention are also useful for the development or modification of methods to process lignocellulosic materials. The methods are useful to modify or improve handling characteristics of lignocellulose-containing materials such as viscosity, as well as reduce feedstock bulk and particle size, which can be useful in liberation of sugars, use as a feedstock, or in preparation of the lignocellulose for use of further methods. Further, the methods of the invention can be used to reduce waste bulk, and to improve waste properties from industrial processes that generate lignocellulosic waste. Particularly the methods will be useful to reduce water content, and / or increase dryability, nutritive value or composition.

[0042] In one embodiment, the chemical treatment reduces the number of biological contaminants present in the lignocellulosic feedstock. This may result in sterilization of the feedstock. (

Problems solved by technology

However, this enormous resource is under-utilized because the sugars are locked in complex polymers.

However corn grain is expensive, and has other high value uses, such as use in livestock feeds, and high fructose corn syrups (Wyman, ed.

In contrast, the carbohydrates comprising lignocellulosic materials such as corn stover are more difficult to digest.

Such chemical pretreatments degrade hemicellulose and / or lignin components of lignocellulose to expose cellulose, but also create unwanted by-products such as acetic acid, furfural, and hydroxymethyl furfural.

The harsh conditions needed for chemical pretreatments require expensive reaction vessels, and are energy intensive.

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