Hydrolysis of cellulose by cellulase-mimetic solid catalyst

Abstract

A novel cellulase-mimetic solid catalyst, sulfonated chloromethyl polystyrene resin (CP-SO₃H), containing cellulose-binding sites (–Cl) and catalytic sites (–SO₃H) was synthesized for hydrolyzing cellulose. Cellobiose could be completely hydrolyzed in 2–4 hours at 100–120 °C by CP-SO₃H, and microcrystalline cellulose (Avicel) could be hydrolyzed into glucose with a yield of 93% within 10 hours at moderate temperature (120 °C). The apparent activation energies for the hydrolysis of cellobiose and Avicel with CP-SO₃H were approximately 78 and 83 kJ mol⁻¹, respectively, which are much lower than those for the hydrolysis of cellobiose and cellulose with sulfuric acid (133 and 170 kJ mol⁻¹, respectively) but higher than that with cellulase (3–50 kJ mol⁻¹). Low activation energy allows the CP-SO₃H-catalyzed hydrolysis to proceed at low temperature, which reduces energy consumption and avoids undesirable sugar degradation. The low activation energy of CP-SO₃H might be attributed to its ability to adsorb/attract cellobiose and cellulose and to disrupt hydrogen bonds of cellulose.