Rational approach to optimize cellulase mixtures for hydrolysis of regenerated cellulose containing residual ionic liquid

Enzymatic hydrolysis of lignocellulosic polysaccharides in the presence of ionic liquids

“…T. reesei Cel7A (cellobiohydrolase) and Cel7B (endoglucanase) were in one study found to be inactivated in a similar manner in the presence of [DMIM]DMP, with some residual activity in 30% (v/v) of this IL. 150 The β-glucosidase of A. niger was more IL sensitive and lost its activity already in 15% (v/v) of [DMIM]DMP. 150 Cellulase inactivation in aqueous [DMIM]-DMP has been found to be reversible, and also the storage stability has been found to be sufficiently steady for long hydrolyses in 10% (v/v) [DMIM]DMP, after a first initial rapid decrease in the activity.…”

“…106 Engel et al optimized a cellulase cocktail for the hydrolysis of regenerated α-cellulose in the presence of 10% (v/v) [DMIM]DMP based on inactivation data acquired for the cellulases T. reesei Cel7A and Cel7B and A. niger β-glucosidase in this IL. 150 In several articles whole cell cultures have been studied under conditions similar to those in the hydrolysis of IL-pretreated biomass for developing IL-tolerant enzyme systems. [190][191][192] In addition to the need for IL-tolerant cellulase cocktails, the increased amorphous character of regenerated cellulosic substrates emphasizes the role of endoglucanases in total hydrolysis, as they apparently have much larger target regions in the substrate.…”

Swollenin aids in the amorphogenesis step during the enzymatic hydrolysis of pretreated biomass

“…This cellulase mixture includes a variety of well-studied glycosyl hydrolases, including cellulases and hemicellulases (Engel et al, 2012;Saloheimo and Pakula, 2012). More recently it has been shown that some fungi, including Hypocrea jecorina, also produce a class of oxidative enzymes, known as polysaccharide mono-oxygenases, which directly cleave cellulose chains through an oxidative mechanism, and appear to act synergistically with the canonical hydrolytic enzymes (Harris et al, 2010;Quinlan et al, 2011;Vaaje-Kolstad et al, 2010).…”

The emergence of Clostridium thermocellum as a high utility candidate for consolidated bioprocessing applications

“…In addition, the acid-catalyzed hydrolysis of cellulose generates carbohydrate-derived dehydration products, which are undesirable for the cellulase-based deconstruction of cellulose (Kumar et al, 2013). Recently, studies have been conducted to improve the efficiency and decrease the cost of the enzymatic hydrolysis process using recombinant technologies (Fang and Xia, 2013), ionic liquids (Engel et al, 2012), accessory enzymes (Hu et al, 2011), and alterations of plant cell wall structure focused on modification to their lignin content (Chen and Dixon, 2007; Hisano et al, 2009; Fu et al, 2011; Shen et al, 2013), however, this stage still remains as the main bottleneck preventing cost efficiency. Therefore, as an alternative, the direct saccharification of lignocellulosic biomass has similarly been investigated, but has been shown to negatively impact the efficiency of enzymatic hydrolysis when compared to the saccharification of pretreated substrates in a variety of biomass sources (Intanakul et al, 2003; Zhang et al, 2007a,b).…”