Publication (UJEP): Adhesion of Megasphaera cerevisiae onto solid surfaces mimicking materials used in breweries

Developments in filling technologies have led to a reduction in oxygen content in beer, thus producing an anaerobic environment suitable for the growth of anaerobic beer-spoiling microorganisms. Anaerobic bacteria survive well in a biofilm that provides protection against environmental stress factors. The initial step in biofilm formation is adhesion of cells to a solid surface.ThereforethepurposeofthisresearchwastostudytheoreticallyandexperimentallyadhesionofstrainsofMegasphaera cerevisiae to different solid surfaces with properties covering a wide range of materials used in breweries. Experimental characterizationofsurface properties wasusedtomodelsurface interactions,resulting ina quantitative predictionofcell adhesion. The colloidal model predictions were thencompared with adhesion tests.As revealed experimentally, the most significant adhesion occurred to 3-aminopropyltriethoxysilane-modified glass (substitute for stainless steel) at pH 3–7. According to physicochemical interaction models, under these conditions interactions were influenced mostly by electrostatic attractions between surfaces. At pH 3, experimental data, supported by theoretical predictions, showed significant bacterial adhesion to borosilicateglass(ahydrophilicsurface)andpropyltriethoxysilane-modifiedglass(ahydrophobicsurface).Conversely,theleast adhesion of M. cerevisiae was both predicted and observed at pH 10, since at an alkaline pH, electrostatic repulsion between surfacespredominates.SinceadhesioncanbeexpectedmainlyatanacidicpH,preventionshouldbebasedontheuseofalkaline cleaning agents and/or alkaline rinse water at the end of the cleaning procedure. An elevated risk of adhesion to stainless steel was also identified, allowing appropriate measures to be taken.

Bittner M., Strejc J., Matoulkova D., Kolska Z., Pustelnikova L, Branyik T.: „Adhesion of Megasphaera cerevisiae onto solid surfaces mimicking materials used in breweries“, JOURNAL OF THE INSTITUTE OF BREWING, 123 (2017) 204-210. DOI: 10.1002/jib.415. Spolupráce s VŠCHT Praha. UJEP (WP3) IF = 0,859. DOI 10.1002/jib.415

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