Development of an enzymatic cascade to systematically utilize lignocellulosic monosaccharide

Area of Science:

• Biotechnology
• Biomass Valorization
• Enzymatic Catalysis

Background:

• Fermentation of lignocellulosic sugars (glucose, xylose) is limited by yield and complexity.
• In vitro enzymatic cascade reactions present a viable alternative approach.

Purpose of the Study:

• To develop a multi-stage enzymatic cascade for converting lignocellulosic biomass into valuable chemicals.
• To optimize substrate specificity and coenzyme regeneration for efficient conversion.

Main Methods:

• A three-stage, five-enzyme cascade was designed.
• Key enzymes included ribose-5-phosphate isomerase B mutant, d-arabinose dehydrogenase, and glucose dehydrogenase.
• Biomass hydrolysis was performed using cellulase and hemicellulase.

Main Results:

• Xylose was isomerized to d-xylulose and reduced to d-arabitol.
• Glucose facilitated coenzyme regeneration, producing gluconic acid, with a 73% total conversion rate after 36 hours.
• Corn cob yielded the highest monosaccharide content; 65% conversion of lignocellulosic xylose was achieved in 24 hours.

Conclusions:

• Demonstrated a proof of concept for systematic conversion of lignocellulosic monosaccharides using an enzymatic cascade.
• Achieved stoichiometric conversion ratios, highlighting the potential for industrial applications.