New species of cold-tolerant yeast could yield better lager

Phenotypic chatacteristics of Saccharomyces jurei sp. nov. D5088T. Photomicrograph of the asci (left) and scanning electron micrographs of ascospores (right) formed on acetate agar after 5 days at 25 °C. Bars, 2 µm // Images via Microbiology Society

Phenotypic chatacteristics of Saccharomyces jurei sp. nov. D5088T. Photomicrograph of the asci (left) and scanning electron micrographs of ascospores (right) formed on acetate agar after 5 days at 25 °C. Bars, 2 µm // Images via Microbiology Society

Yeast—it ferments our beer, leavens our bread, and is found virtually everywhere on earth. But despite the many thousands of yeast strains catalogued in collections around the world, it’s estimated that we’ve only identified perhaps as little as 10 percent of what exists in nature. Thanks to a group of researchers at the University of Manchester, that number just got a tiny fraction bigger with the discovery of a new species of yeast in the Saccharomyces family.

The research team, in collaboration with the National Collection of Yeast Cultures (NCYC), discovered the new yeast strain on an oak tree in Saint Auban, in the foothills of the French Alps. More importantly for brewers is the fact that the oak tree was growing 3,000 feet above sea level. To survive at that altitude, the yeast developed an ability to tolerate colder conditions than most other known strains of Saccharomyces yeasts, making it a prime candidate for lager beer production.

“This ability is of interest to brewers, as lagers rely on yeasts that thrive in the cold; it also open the opportunity to create arrays of novel yeast hybrids with improved biotechnological traits,” said Professor Daniela Delneri, from the Manchester Institute of Biotechnology at The University of Manchester.

According to Dr. Steve James from NCYC, which is based on the Norwich Research Park, the yeast strain is the first new species belonging to the brewing yeast family to be discovered since 2011. “It’s really exciting to find this new Saccharomyces yeast, as it extends even further the genetic diversity from which we can draw in the yeast gene pool,” James said.

With the vast majority of known yeasts derived from lower altitudes, the search for greater yeast diversity drove the team from the University of Manchester to search for new yeasts higher above sea level. Dozens of different yeast samples were collected from oak trees, which are a particularly rich source of yeasts, and surrounding soils, and cold-tolerant strains were isolated based on their ability to grow at lower temperatures than most other yeasts.

The strains were brought to the team at NCYC for testing, and while most of the isolates were found to be known species, two were confirmed through DNA sequencing and genetic testing to belong to an entirely new species.

Dr. Samina Naseeb, a research associate from the University of Manchester, added, “It was incredibly exciting when we realized that we discovered a new cold-tolerant species which can also ferment maltose efficiently.”

The species was named Saccharomyces jurei in memory of the yeast researcher Professor Jure Piškur.

 
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