Method for reducing viscosity in saccharification process

Abstract

The present invention relates to compositions that can be used in hydrolyzing biomass such as compositions comprising a polypeptide having glycosyl hydrolase family 61 / endoglucanase activity, methods for hydrolyzing biomass material, and methods for reducing viscosity of biomass mixture using a composition comprising a polypeptide having glycosyl hydrolase family 61 / endoglucanase activity.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of U.S. Provisional Application No. 61 / 453,923, filed Mar. 17, 2011, which is hereby incorporated by reference in its entirety.FIELD OF THE INVENTION[0002]The present invention relates to compositions useful for hydrolyzing biomass, methods of using such compositions to hydrolyze biomass materials, and methods for reducing viscosity of biomass saccharification mixtures.BACKGROUND OF THE INVENTION[0003]Bioconversion of renewable lignocellulosic biomass to a fermentable sugar that is subsequently fermented to produce alcohol (e.g., ethanol) as an alternative to liquid fuels has attracted the intensive attention of researchers since the 1970s, when the oil crisis occurred (Bungay, H. R., “Energy: the biomass options”. NY: Wiley; 1981; Olsson L, Hahn-Hagerdal B. Enzyme Microb Technol 1996, 18:312-31; Zaldivar, J et al., Appl Microbiol Biotechnol 2001, 56: 17-34; Galbe, M et al., Appl Microbiol Biotechnol 20...

AI Technical Summary

Benefits of technology

The patent text is based on the discovery that adding a certain enzyme called endoglucanase can reduce the viscosity of a mixture of biomass and improve the yield of desirable fermentable sugars. The patent also offers methods for reducing the viscosity of the biomass mixture by adding the endoglucanase enzyme. The viscosity of the mixture can be reduced by at least 5% compared to a control mixture without the endoglucanase enzyme. The biomass materials can include hemicellulose, cellulose, glucan, xylan, lignin, or a mixture of these. The endoglucanase enzyme can increase the yield of fermentable sugars by at least 5%. Overall, the patent offers a solution for improving the efficiency of biomass saccharification.

Problems solved by technology

These early processes were primarily directed to acid hydrolysis, which were complex in engineering and design, and were typically sensitive to small variations in the processes, such as to temperature, pressure and / or acid concentrations.

The abundant supply of petroleum in the period from World War II through the early 1970s slowed ethanol conversion research.

Uncertainty remains with these processes, mainly on their ability to be scaled up for commercialization and on the efficiency of ethanol production.

Organisms are often restrictive with regard to which sugars they use, and this dictates which sugars are best to produce during conversion.

A whole cellulase, especially one that is naturally occurring, is, however, not necessarily capable of achieving efficient degradation because it may not include all the components / activities required for this efficiency, for example, activities from each of the CBH, EG and BG classifications.

However, the results of many studies demonstrate that the yield of expressing bacterial enzymes from filamentous fungi is low (Jeeves et al., 1991).

However a common problem associated with saccharifying a high dry matter biomass is the high viscosity of the slurry, resulting in a slurry that is not pumpable or requires large energy input during handling.

When dealing with handling of high solids, problems such as 1) insufficient mixing with limited mass transfer, 2) increasing concentration of inhibitors, such as acetic acid, furfural, 5-hydroxymethyl furfural, phenolic lignin degradation, 3) production inhibition, such as glucose, cellobiose, ethanol, and 4) fermentation microorganism viability, will occur.

High viscosity limits the dry substance level in the process, increasing energy and water consumption, reducing the separation efficiency, evaporation and heat exchange, and ultimately, the ethanol yield.

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