title: FLO11-based model for air-liquid interfacial biofilm formation by Saccharomyces cerevisiae.
abstract: Sardinian wine strains of Saccharomyces cerevisiae used to make sherry-like wines form a biofilm at the air-liquid interface at the end of ethanolic fermentation, when grape sugar is depleted and further growth becomes dependent on access to oxygen. Here, we show that FLO11, which encodes a hydrophobic cell wall glycoprotein, is required for the air-liquid interfacial biofilm and that biofilm cells have a buoyant density greater than the suspending medium. We propose a model for biofilm formation based on an increase in cell surface hydrophobicity occurring at the diauxic shift. This increase leads to formation of multicellular aggregates that effectively entrap carbon dioxide, providing buoyancy. A visible biofilm appears when a sufficient number of hydrophobic cell aggregates are carried to and grow on the liquid surface.
authors.affiliation: Dipartimento di Scienze Ambientali Agrarie e Biotecnologie Agroalimentari, Sezione di Microbiologia Generale ed Applicata, Università di Sassari, Viale Italia 39, 07100 Sassari, Italy.
authors.forename: Severino
authors.initials: S
authors.lastname: Zara
authors.forename: Alan T
authors.initials: AT
authors.lastname: Bakalinsky
authors.forename: Giacomo
authors.initials: G
authors.lastname: Zara
authors.forename: Giorgia
authors.initials: G
authors.lastname: Pirino
authors.forename: Maria Antonietta
authors.initials: MA
authors.lastname: Demontis
authors.forename: Marilena
authors.initials: M
authors.lastname: Budroni
mesh_terms: D000388:Air; D018441:Biofilms / Q000254:growth & development*; D003470:Culture Media; D000431:Ethanol; D005285:Fermentation; D015966:Gene Expression Regulation, Fungal; D057927:Hydrophobic and Hydrophilic Interactions; D007218:Industrial Microbiology; D008562:Membrane Glycoproteins; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D013499:Surface Properties; D014920:Wine / Q000382:microbiology
chemical_list: D003470:Culture Media; C110690:FLO11 protein, S cerevisiae; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D029701:Saccharomyces cerevisiae Proteins; D000431:Ethanol