Acid hydrolysis of lignocellulosic biomass with minimum dosage of acid catalyst

Abstract

This specification describes a process of producing a monomeric sugar stream, with little or no acid addition, from an oligomeric sugar solution using the intrinsic features of the mildly pre-treated vegetable or ligno-cellulosic biomass, namely the presence of naturally occurring salts. This is accomplished by lowering the pH of the oligomer sugar solution with little or no addition of an acid and then exposing the biomass with the lowered pH to an elevated temperature greater than 80° C. for a time sufficient to hydrolyze the components of the biomass.

Description

technical background [0001] Acid hydrolysis of biomass and cellulose is known in the art. It is implemented in a homogeneous or heterogeneous manner. [0002] Processes that typically obtain monomeric sugar streams from oligosaccharide streams from pretreated lignocellulosic material (eg, autohydrolysis, hot water washing, or steam explosion) seek to limit the monomeric sugars during post-hydrolysis of the oligosaccharides to monomers. Sugars are converted into degradation products. (Duart et al., 2004; Girio et al., 2010). [0003] Post-hydrolysis, also known as hydrolysis, for the hydrolysis of xylo-oligosaccharides (XOs), options are acid-catalyzed (Boussaid et al., 2011;), or an enzymatically catalyzed process (Duarte et al., 2004) (Carvalheiro et al. People, 2008). [0004] The main factors affecting monosaccharide recovery in dilute acid chemical post-hydrolysis are catalyst concentration, reaction time and temperature. The acid process is applied to hydrolyzates ob...

AI Technical Summary

Problems solved by technology

Since complex hemicellulose structures can still be present in oligosaccharides obtained from pretreatment, some enzymatic activity is usually required for complete hydrolysis (e.g., endoxylanase, exoxylanase, β-xylosidase and auxiliary activities such as acetylxylan esterase, α-glucuronidase, α-arabinofuranosidase and feruloesterase); thus the process may become uneconomical (Vazquez et al. , 2002; Duarte et al., 2009)

Additionally, toxic / inhibitor compounds that may be present in this hydrolyzate can significantly reduce enzyme activity (Carvalheiro et al., 2008)

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