Synthesis of Recyclable UCST-Type Copolymer PPSP and Its Application in Enhancing Lignocellulosic Enzymatic Hydrolysis and Recycling Cellulase

The cost of lignocellulosic enzymatic hydrolysis can be reduced by adding additives with upper critical solution temperature (UCST) response. A recyclable UCST-type copolymer PPSP was synthesized, for enhancing lignocellulosic enzymatic hydrolysis and the cellulase recovery effect of substrate reabsorption. For the hydrolysis system of corncob residue without adding PPSP, only 50% of cellulase amount was saved at a room temperature of 25 °C by adding the fresh corncob residue. The substrate enzymatic digestion efficiency for 72 h was increased by 1.3 times with only adding 0.5 g/L PPSP10-3. After the hydrolysis, 70% of cellulase amount was saved at 25 °C by using the above method. Both lignocellulosic hydrolysis and recovery of cellulase performances were improved by adding PPSP. This may be attributed to the fact that PPSP preferentially adsorbed on lignin to form a hydration membrane to reduce the no-productive adsorption of cellulase and enhanced lignocellulosic enzymatic hydrolysis, while increasing the concentration of free cellulase in the system and strengthening recovery of cellulase. This work will provide one way to reduce the cost of lignocellulosic enzymatic hydrolysis.