Characterization of acid catalytic domains for cellulose hydrolysis and glucose degradation

Abstract

Cellulolytic enzymes consist of a catalytic domain, a linking peptide, and a binding domain. The paper describes research on carboxylic acids that have potential as catalytic domains for constructing organic macromolecules for use in cellulose hydrolysis that mimic the action of enzymes. The tested domains consist of the series of mono-, di-, and tricarboxylic acids with a range of pK(a)'s. This paper systematically characterizes the acids with respect to hydrolysis of cellobiose, cellulose in biomass, and degradation of glucose and compares these kinetics data to dilute sulfuric acid. Results show that acid catalyzed hydrolysis is proportional to H+ concentration. The tested carboxylic acids did not catalyze the degradation of glucose while sulfuric acid catalyzed the degradation of glucose above that of water alone. Consequently, overall yields of glucose obtained from cellobiose and cellulose are higher for the best carboxylic acid tested, maleic acid, when compared to sulfuric acid at equivalent solution pH.

Optimizing Dilute-acid Hydrolysis (DACH) of Distillers Grains and Ethanol Fermentation

“…One reason was that more hydrogen ions led to a higher degradation rate of hemicelluloses and cellulose, producing more RS and xylose. However, higher sulfuric acid concentration will cause the formation of inhibitors compounds (furfural and HMF), due to the increase in the activity of hydrogenions participating in the reaction as catalyst [23]. These results are in accordance with Meineta et al [21].…”

Influence of hot water extraction on cell wall and OSB strand mechanics

“…These four extraction conditions were equated to a severity factor (SF) through the use of Eq. (1) (Overend and Chornet 1987;Mosier et al 2002).…”

“…, assuming that the overall process is hydrolytic and the overall conversion is pseudo-first order (Overend and Chornet 1987;Mosier et al 2002). Bonds on SF equation are from 0 (unextracted wood) to 4.…”

Fungus-Assisted Acetic Acid Pre-Treatment of Eucommia ulmoides Oliver Seed Shells for Enhancement of Enzymatic Hydrolysis

“…According to recent studies (Mosier et al 2002(Mosier et al , 2005Wyman et al 2005), the weight losses of seed components is caused by the activities of various extracellular ligninolytic oxidoreductases that are produced by rot fungi, which efficiently facilitates the degradation of lignin in many lignocellulosic materials. Simultaneously, some sugars may be consumed as energy or carbon sources during fungal fermentation.…”

“…Because they consume less energy and are less damaging to the environment, biological pre-treatments, including cellulosebinding domain treatment (Hall et al 2011) and fungal pre-treatment (Mosier et al 2002;Mosier et al 2005;Wyman et al 2005), are the most environmentally friendly processing approaches. Biological pre-treatments of lignocellulosic material with rot fungi results in the degradation of lignin and some selective hemicelluloses, which increases the accessibility of cellulose during subsequent enzymatic hydrolysis and fermentation, and improves the total enzymatic hydrolysis rate (Wan and Li 2010;Shaikh et al 2011).…”