New bio-protection yeast strain kills Brettanomyces

ould this be the first step towards the end of farmyard, sweat and horse urine smells? It is certainly a major innovation that Canadian firm Lallemand Oenology is preparing to make commercially available. Stemming from a collaboration with the South African Grape and Wine Research Institute, LEVEL2 SALVA™ is a non-Saccharomyces bioprotection yeast designed to specifically combat Brettanomyces bruxellensis during the pre-fermentative stages of wine production. “It comes from South Africa’s Stellenbosch University collection”, explains Anthony Silvano, head of yeast products with Lallemand. “It is a Suhomyces pyralidae, a species that was unknown until now, which produces an inhibition factor ‘Spkt1’ meaning Suhomyces pyralidae killer toxin”, he adds.

“The inhibition factor disrupts the cell walls of Brettanomyces. The most probable hypothesis is that an enzyme creates holes in the Brettanomyces yeast cell walls, causing them to die and thereby inhibiting their spread in the pre-fermentative phase”. And only in the pre-fermentative phase because the yeast cannot withstand alcohol – “from 2 to 3% alcohol, it dies”.

Selected from Cabernet-Sauvignon in South Africa, the strain required four years of trials before being ready for market. “We conducted pilot and field trials with real winemaking conditions, monitoring Brett and ethyl-phenol populations. Every time, we either achieve total eradication of the Brettanomyces, or trace elements of the yeast. The inhibition factor has no persistence. If the wine is contaminated again with Brettanomyces during the maturation phase, obviously it will occur in the wine”.