Yeast engineering produces animal-free, high-quality chondroitin sulfate

Chinese researchers have found a new way to produce high-quality chondroitin sulfate, often used for joint health and osteoarthritis, without relying on animals.

They engineered yeast to produce the compound, overcoming a long-standing issue. The researchers note that microbial production often achieves high product volume or quality, but not both.

By using genetic and metabolic engineering, the team created a yeast strain, Komagataella phaffii, that could produce a high volume of chondroitin sulfate with strong sulfation. 

The Zhejiang University researchers add that this method offers a safer, more sustainable, and more consistent alternative to animal cartilage, as they pose supply and safety challenges.

The team says that chondroitin sulfate also offers anti-inflammatory, anticoagulant, and anticancer benefits, which broaden its pharmaceutical and nutraceutical value.

In industry developments, Gnosis by Lesaffre told Nutrition Insight that it is applying precision fermentation to chondroitin sulfate, delivering a highly consistent, non-animal ingredient with clinically proven improvements in absorption and joint health outcomes.

Relying on animals drives supply challenges

The study in BioDesign Research points out that mainstream commercial production of chondroitin sulfate is almost fully reliant on extraction from animal cartilage, such as cows, pigs, and sharks.

The researchers note that using animal derivatives is leading to challenges, such as limited raw supply, long production cycles, quality variability, and safety concerns related to allergens and zoonotic pathogens.

They add that these challenges are driving interest in microbial biosynthesis, but the main challenge has been achieving efficient and site-specific sulfation in microbes.

Engineering experiments

The researchers combined three unique genes to boost biosynthesis and optimize sulfation in the chondroitin producer K. phaffii. These were kfoC and kfoA from Escherichia coli K4 and tuaD from Bacillus subtilis.

The most optimal gene arrangement required each gene to be expressed separately and constantly active. This led to a high production of chondroitin — about 927 mg/L, which is double that of a simpler design.

Additionally, enzyme CHST11 was added to attach sulfate groups to the chondroitin. 

First, the researchers found that the most effective setup for the enzyme involved the human version of CHST11 with a tag called TrxA and a specific promoter, leading to around 2% sulfation production.

For higher sulfation, the team engineered CHST11 into a mutant called SMp. One copy of this mutant increased sulfation to 12%, while adding multiple copies increased sulfation to 45%, with chondroitin production exceeding 1.2 g/L.

Furthermore, the researchers observed that the yeast was running out of the sulfate donor that it needs, so they altered metabolic pathways where overexpressing native yeast genes — PPK and BPNT — pushed sulfation up to 48%.

The new yeast was grown in a controlled fermentation process without adding extra sulfate, where 7.13 g/L of chondroitin sulfate maintained a stable 48% sulfation and a high molecular weight (~234 kDa).