Peptide Sweeteners secreted from yeast

A new technical white paper from ARTES Biotechnology describes its precision-fermentation production of peptide sweeteners, using the yeast Hansenula polymorpha.

Peptide sweeteners deliver intense sweetness while contributing very few calories. Examples include brazzein and monellin, which are several thousands of times sweeter than sucrose by weight. ARTES’ production technology is free from antibiotics, antibiotic-resistance genes and methanol, supporting safe, sustainable and scalable manufacturing for food and animal-feed applications.

“Peptide Sweeteners Produced by Precision Fermentation of the Yeast Hansenula polymorpha” explains how microbial fermentation can provide a more efficient and scalable alternative to extracting peptide sweeteners from tropical plants. Eliminating the use of antibiotic-resistance genes as selection marker and of antibiotics in the manufacturing process addresses concerns about residues and horizontal gene transfer, while methanol-free production reduces costs and supports safer large-scale processing.

The paper describes how H. polymorpha strains are engineered to secrete high concentrations of sweet proteins. Strong promoters, specialised secretion leaders and the integration of multiple copies of an optimised target gene are used to achieve high productivity. The secreted proteins contain few impurities, simplifying downstream purification.

Brazzein and Monellin

Brazzein was originally isolated from the fruit of the West African climbing plant Pentadiplandra brazzeana. Its major form is approximately 750 times sweeter than sucrose by weight. ARTES has achieved secreted brazzein concentrations of several grams per litre in synthetic media. A simple, single-step purification process produces brazzein with a purity of more than 99%, replacing conventional chromatography with a substantially less expensive alternative.

Monellin occurs naturally in the fruit of the West African plant Dioscoreophyllum cumminsii. It is approximately 4,000 times sweeter than sucrose by weight. ARTES has also achieved concentrations of several grams per litre using an engineered, monellin-secreting H. polymorpha strain.

The recombinant production strains have demonstrated genetic stability over hundreds of generations under non-selective conditions. Concentrations approaching 5 g/L have been achieved for both brazzein and monellin, with few impurities and straightforward purification.

The white paper concludes that ARTES has established robust and scalable processes suitable for industrial scale manufacturing of these low-calorie sweet proteins. The brazzein and monellin processes are ready for technology transfer and available for short-term licensing.