Pediococcus damnosus strains isolated from a brewery environment carry the horA gene

Beer is recognized as a safe beverage, owing to its excellent microbiological stability provided by its components, especially iso-a-acids from hop and ethanol which have antimicrobial activity. Despite these unfavourable conditions for bacteria, some lactic acid bacteria (LAB) can cause beer spoilage. Resistance to hop compounds is caused, in part, by the product of genes like horA. Understanding how LAB adapts to hop compounds as well as quick detection of these microorganisms is necessary to ensure high-quality beverages produced by the brewing industry. In this work, we searched for the presence of two main hop-resistance genes, horA and ORF5, and determined the capacity of four strains of Pediococcus damnosus isolated from a brewery environment to grow in the presence of increasing concentrations of iso-a-acids. All strains were able to grow in increasing concentrations of iso-a-acids up to 150 mu g mL(-1). This amount is 10 times greater than the concentration in average beer. Genetic amplification of genes associated with hop-resistance, demonstrated the presence of horA, but not ORF5 in all tested strains. This communication represents the first report of the presence of horA gene in bacteria isolated from breweries in our country. (C) 2017 The Institute of Brewing & Distilling