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Em busca de bacteriófagos para a bioconservação de alimentos e bebidas
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Orientador(es)
Resumo(s)
The fruit juice industry has faced increasing incidents of spoilage attributed to bacteria of the genus Alicyclobacillus. These spore-forming bacteria produce compounds responsible for undesirable odours and flavours, compromising product quality, causing food waste, economic losses, and reducing consumer confidence. The resistance of Alicyclobacillus to acidic environments and to pasteurisation processes used in the food industry justifies the search for new biopreservation strategies. Among these, bacteriophages emerge as a promising, safe, ecological, and sustainable alternative. In this work, methodologies for the isolation, purification and amplification of bacteriophages were applied using different environmental samples considered potential reservoirs of Alicyclobacillus and associated phages. Of the samples tested, only one, originating from vineyard soil, produced phage plaques when using Alicyclobacillus acidoterrestris DSM 3922T as the host. Phage purification was only possible using the alternative strain A. acidoterrestris TAB 21, which enabled the recovery of isolated phage plaques after successive purification cycles. Different conditions were also tested to optimise diffusion, recovery, stability, and maintenance of the phage’s infectious activity. Liquid BAT medium, a culture medium developed for the growth of A. acidoterrestris, at pH 4 and 45 °C proved to be the most suitable for preserving its viability. The plate flooding method allowed the obtainment of high titres, allowing for the extraction and purification of nucleic acids, confirmed as intact double-stranded DNA through spectrophotometry, fluorometry and gel electrophoresis.
Descrição
Tese de Mestrado, Microbiologia Aplicada, 2025, Universidade de Lisboa, Faculdade de Ciências
Palavras-chave
Alicyclobacillus genus Spoilage Biopreservation Bacteriophages