A REVIEW ON USING MEMBRANE REACTORS IN ENZYMATIC HYDROLYSIS OF CELLULOSE

Abstract

Enzymatic hydrolysis of cellulose in the conventional batch reactors is severely affected by product inhibition due to the accumulation of glucose inside. The approach of using ultrafiltration membranes has created an effective way for simultaneously glucose removal and enzyme recovery with two main configurations of membrane reactors developed by many researchers. This short review aims at examining the main features of external loop and submerged membrane reactors, i.e. its operation conditions such as substrate concentration, enzyme to substrate ratio, and mixing which affect the performance of hydrolysis in term of conversion, glucose formation, concentration polarisation and fouling. Challenges of membrane reactors were realised as low output glucose concentration, unsuitable to run at high cellulose concentrations, and the total recovery of enzymes adsorbed in the solid cellulose and liquid hydrolysate. Besides that, other two new configurations (dialysis and the modified membrane reactor) are highlighted as very potential methods to not only effectively remove glucose for minimising product inhibition and recover enzymes but also able to handle higher cellulose concentrations form 10% or higher. Further research should focus on the degree of glucose removal from hydrolysis reaction membrane reactor systems, and operational feasibility in disposal of unconverted substrate after hydrolysis.

Keywords

• Membrane reactors
• Ultrafiltration
• Inhibition
• Glucose removal
• Enzymatic hydrolysis.