HSP12 is essential for biofilm formation by a Sardinian wine strain of S. cerevisiae.

Sardinian sherry strains of S. cerevisiae form a biofilm on the surface of wine at the end of the ethanolic fermentation, when grape sugar is depleted and when further growth becomes dependent on access to oxygen. A point mutation in HSP12 or deletion of the entire gene results in inability to form this film. HSP12 encodes a heat-shock protein previously foundby others to be active during stationary phase, in cells depleted for glucose, and in cells metabolizing ethanol and fatty acids, all conditions associated with sherry biofilms.