Abstract

Hydroxycinnamic acids are lipophilic compounds naturally present in grape must, and proposed to have antimicrobial properties. Consequently, microorganisms that grow in media containing these acids must have efficient adaptation mechanisms. In Saccharomyces cerevisiae hydroxycinnamic acids enter into the cell where they are deprotonated causing a decrease in internal pH, this variation in the intracellular pH is counteracted by an increase in the activity of the H⁺- ATPase pump Pma1p. Dekkera bruxellensis however, is able to transform hydroxycinnamic acids into volatile-less toxic derivates, a mechanism used by few yeast species. Nonetheless, D. bruxellensis could also have an adaptation mechanism similar to that of S. cerevisiae. Our results showed that hydroxycinnamic acids caused a longer lag phase during D. bruxellensis growth, particularly when supplementing media with ferulic acid. Additionally, extracellular pH decreased while Pma1p activity increased during lag phase in media supplemented with p-coumaric acid. These results suggest the existence of a complementary mechanism of resistance to hydroxycinammic acids in D. bruxellensis which involves the H⁺- ATPase pump Pma1p.

Key words: Dekkera bruxellensis, H⁺-ATPase Pma1p, p-coumaric acid.