Adding a cationic polyacrylamide (c-PAM) to either the amylase mediated hydrolysis of corn starch or the hydrolysis of wood fiber by cellulase can enhance the initial hydrolysis rates, although a rate decrease can occur under some conditions. Several c-PAMs can serve as catalysts and the same c-PAM can improve the efficiency of both amylase and cellulase. The initial amylase rate approximately doubles; the analogous cellulase hydrolysis rate increases by about 40%. c-PAMs increase the binding of enzyme to substrate.
in Wiley Online Library (wileyonlinelibrary.com).Cationic polyacrylamides (c-PAMs) bind to starch granules and decrease the temperature for the onset of gelatinization by 8 C. c-PAM increases the binding of -amylase to cornstarch; the rate of cornstarch hydrolysis also increases. By analogy to previous work on the c-PAM promoted hydrolysis of cellulose, it is proposed that the polymer reduces the charge on the surface of starch through a charge-patch mechanism. Because both enzyme and substrate are negatively charged, the bound c-PAM reduces the charge repulsion experienced by the approaching enzyme, which leads to stronger enzyme-substrate binding and faster hydrolysis. Overall, the c-PAM reduces enzyme dose by up to 62% under the conditions used. There is a mirror image relationship between the viscosity of the medium and the hydrolysis rate, which allows optimization of these parameters with enzyme and c-PAM dosage. Low c-PAM levels increase viscosity by agglomerating the substrate, but the viscosity drops at higher c-PAM concentration.
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