Bioconversion platform for lactose-to-rare sugar production

Overview

This research program develops a recombinant enzyme-based bioconversion platform that transforms lactose, a abundant dairy byproduct, into valuable rare sugars including allulose and tagatose. These sugars offer a rare sugar blend approximately 80% as sweet as sugar while providing only about 1.0 kcal/g, making them attractive low-calorie alternatives for food and beverage manufacturers.

The technology supports sustainable dairying by adding value to lactose streams that would otherwise require disposal or low-value processing. By converting lactose into high-demand functional ingredients, dairy producers and ingredient suppliers can diversify revenue while reducing environmental impact. Potential applications include sugar reduction in beverages, baked goods, confectionery, and dairy products where allulose and tagatose can deliver sweetness with significantly fewer calories.

Technical specifications

Core approach:

• Recombinant enzymes cloned and expressed for lactose hydrolysis and subsequent isomerization reactions
• Lactase enzymes hydrolyze lactose into glucose and galactose
• L-arabinose isomerase and D-allulose epimerase convert sugars into allulose and tagatose
• Single-reaction-vessel conversion following lactose hydrolysis streamlines processing

Enzyme development status:

• Successfully cloned lactase, glucose isomerase, L-arabinose isomerase, and D-allulose epimerase from multiple sources
• Enzymes isolated using His-tag purification and nickel affinity resin
• HPLC methods developed for sugar analysis and quantification
• Ongoing evaluation to identify optimal enzyme combinations for maximum yield

Whole-cell bioconversion:

• Exploring yeast-based whole-cell applications for extracellular rare sugar production
• Leveraging established expression technologies to enable scalable, cost-effective bioconversion

Target product profile:

• Rare sugar blend composition of approximately 50% allulose and 50% tagatose
• Sweetness equivalent to roughly 80% of sucrose
• Caloric content of approximately 1.0 kcal/g

Technology readiness level

The platform is currently at an early-to-mid development stage. Core enzymes required for the sugar conversion system have been successfully expressed and purified, confirming feasibility of the recombinant approach. Optimization efforts are focused on enhancing expression levels, particularly for the glucose isomerase from S. murinus, which has presented unexpected challenges. Future work includes testing alternative thermo-tolerant bacterial glucose isomerases, refining plasmid design for higher expression in E. coli, and developing enzyme fusion methods once the free-enzyme system is fully operational. Transition to whole-cell yeast systems represents the next step toward scalable, production-ready bioconversion.