Abstract Adam LauderdaleAubrey DuBoisYan Ping QianMichael QianJames Osborne

Interactions Between Oenococcus oeni and Brettanomyces bruxellensis during Malolactic Fermentation

Adam Lauderdale, Aubrey DuBois, Yan Ping Qian, Michael Qian, and James Osborne*
*Oregon State University, Wiegand Hall 108A, 3051 SW Campus Way, Corvallis, OR 97331 (James.Osborne@oregonstate.edu)

A rapid malolactic fermentation (MLF) initiated by inoculation of Oenococcus oeni is a useful strategy to prevent Brettanomyces bruxellensis spoilage by minimizing the length of time wine is not protected by SO2. This project investigated an additional benefit of conducting a rapid MLF: the prevention of B. bruxellensis growth due to inhibitory interactions with O. oeni. Pinot noir wine (no SO2, no MLF) was produced and used to test the ability of commercial O. oeni strains to inhibit B. bruxellensis growth at the end of MLF. All 10 O. oeni strains tested inhibited B. bruxellensis UCD2049 growth and volatile phenol production in Pinot noir wine, with some O. oeni strain variation observed. The potential mechanism of this inhibition was investigated by using a dialysis membrane to physically separate O. oeni and B. bruxellensis cells in wine, but to allow free movement of nutrients and other potential inhibitory compounds. Physical separation of O. oeni cells from B. bruxellensis cells relieved the inhi bition of B. bruxellensis by O. oeni that occurred when the two microorganisms were present together. This suggests that inhibition was not due to nutrient depletion by O. oeni and was also unlikely to be caused by an inhibitory compound. Instead, these results provide evidence that the inhibition of B. bruxellensis by O. oeni was due to cell-cell contact. The sensitivity of additional B. bruxellensis strains to O. oeni was also determined. While B. bruxellensis UCD2049 populations declined rapidly when inoculated into Pinot noir wine that had just completed MLF with O. oeni Alpha, growth of seven other B. bruxellensis strains was not affected. Subsequent experiments showed that ethanol tolerance differences between B. bruxellensis strains may have played a role in their sensitivity to repression by O. oeni.

Funding Support: Oregon Wine Board