Yeast-based conversion of lactose to tagatose

Overview

The proposed technology focuses on the development of a specialized yeast strain capable of converting lactose into tagatose, a valuable sugar sweetener. Tagatose is known for its non-cariogenic properties, low caloric value, and prebiotic benefits, making it an ideal alternative to sucrose. Current enzymatic production methods are expensive and inefficient, but our approach aims to achieve over 90% conversion efficiency, offering a sustainable and cost-effective solution for utilizing whey, a cheese production byproduct.

Technical specifications

Our solution leverages a genetically engineered Kluyveromyces lactis yeast strain which can naturally utilize lactose. The strain is modified to suppress galactose utilization while promoting its conversion into tagatose through a series of genetic insertions. Key modifications include:

• GAL1 gene deletion: Prevents galactose utilization.
• Expression of XYL1 from Scheffersomyces stipitis: Converts galactose into galactitol.
• Expression of NAD+-linked galactitol-2-dehydrogenase (GDH): Converts galactitol into tagatose.
• Insertion of additional copies of XYL1, GDH, and LAC4: Enhances tagatose yield and productivity.

The process is designed to use unrefined lactose permeates, making it an efficient one-step conversion at a reduced cost.

Technology readiness level

This technology is currently at TRL 3, where it has undergone experimental validation in a laboratory setting. Future steps include scaling up the process and pilot-scale production to further validate and refine the technology for commercial applications.