Presence of aprX gene in Pseudomonas spp. from refrigerated raw milk and their proteolytic ability

Rosana De Longhi, Samera Rafaela Bruzaroski, Josiane Ito Eleodoro, Regina Celia Poli-Frederico, Rafael Fagnani, Agostinho Ludovico, Elsa Helena Walter de Santana


This study aimed to determine the frequency of Pseudomonas fluorescens, P. putida, and P. aeruginosa in refrigerated raw milk; their proteolytic potential; and your association with the aprX gene. Of the 173 isolates confirmed as belonging to Pseudomonas spp., 37% were P. fluorescens, 25.4% P. putida, and none belongs to P. aeruginosa. The aprX gene was distributed proportionally between P. putida (68%) and P. fluorescens (75%), but it was not associated with low or high proteolytic potential in both species. P. putida (16) and P. fluorescens (14) isolates with no aprX gene identified also had proteolytic potential. Considering the synthesis of proteases other than AprX by the isolates under study, we concluded that P. fluorescens and P. putida represented 62.4% of the Pseudomonas genus, with high probability of having the aprX gene and proteolytic potential. However, there was no association between the deteriorating potential with the presence of the aprX gene.


Psychrotrophic; Enzyme; Quality; Proteolysis.

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Semina: Ciênc. Agrár.
Londrina - PR
E-ISSN 1679-0359
DOI: 10.5433/1679-0359
Este obra está licenciado com uma Licença Creative Commons Atribuição-NãoComercial 4.0 Internacional