Cationic polyacrylamides promote binding of cellulase and amylase

Cationic polyacrylamides increase the rate of liquefaction and hydrolysis of cornstarch

“…A “patching” mechanism was proposed where the polymer attaches to and neutralizes the negatively charged substrate, thereby decreasing the repulsion experienced by the approaching negatively charged enzyme. Stronger enzyme‐substrate binding results . Patching is well‐established in the literature on fiber agglomeration and on water treatment .…”

Mechanism of rate enhancement of wood fiber saccharification by cationic polyelectrolytes

“…The fiber and enzyme preparations were mixed and incubated at 4°C for 1 h with continuous shaking. Previous work has shown that equilibrium is reached within 1 h (Reye et al 2011). The samples were filtered through a 0.2 lm GHP (low protein binding) syringe filter and the protein remaining in solution was assayed with a BCA Protein Assay Kit from Pierce Protein Research Products.…”

“…While modest by catalytic standards, the increase is, nonetheless, commercially significant. We proposed that the polyelectrolyte attaches to and neutralizes the negatively charged substrates thereby reducing the repulsion experienced by the negatively charged enzyme and increasing the binding of the enzyme to the substrate (Reye et al 2011). Charge neutralization of a fiber by a cationic polymer is called ''patching'', a process well established on fiber agglomeration (Hubbe et al 2009).…”

Effects of NIPAm polymer additives on the enzymatic hydrolysis of Avicel and pretreated Miscanthus

“…Electrostatic repulsion would then prevent nonproductive adsorption, analogous to the effects of neutral surfactants. Conflicting mechanisms have also been put forth in which charged or neutral additives increase enzyme association with the substrate, promoting productive binding and leading to greater hydrolysis (Reye et al, ; Seo et al, ). Ethylene‐oxide derived additives are also thought to associate with the substrate surface through hydrophobic (Börjesson et al, ) or hydrogen‐bonding (Sipos et al, ) interactions to prevent nonproductive protein adsorption through steric repulsion.…”

“…While this diverse group of additives has been found to enhance cellulase activity in previous studies, the level at which they do so varies widely based on many factors, including enzyme loading, substrate pretreatment, hydrolysis temperature, and substrate and enzyme choice (Kumar and Wyman, ; Sipos et al, ). Several mechanisms have been proposed to explain the effects of these additives, including the prevention of unproductive enzyme adsorption (Börjesson et al, ), the encouragement of beneficial enzyme‐substrate binding (Kaar and Holtzapple, ; Reye et al, ), decreases in enzyme denaturation due to shearing, heat, or the air–liquid interface (Kaar and Holtzapple, ), and alterations in the substrate structure to increase enzyme binding sites or overall access (Kaar and Holtzapple, ; Seo et al, ). However, the complexity of cellulose hydrolysis and the diversity of the available substrates, enzymes, and additives have prevented a clear understanding from being achieved (Lynd et al, ).…”