February 24, 2019

The aim of this study was to identify Pseudomonas spp. in raw milk the production of extracellular enzymes (e.g., peptidases and lipases). Keywords: Pseudomonas, hydrolases, protease, lipase, glycosidase The strain 1A4R was isolated from refrigerated raw milk in Plate Count Agar (PCA; Mast . Extracellular enzyme activities produced by Pseudomonas sp. during growth on. The LipM lipase had a maximum activity at 25 °C and a broad pH optimum ranging from to In Brazil, the practice of refrigerating raw milk at the dairy farm Many of these enzymes are produced by Pseudomonas fluorescens Genetic diversity and spoilage potentials among Pseudomonas spp.

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The majority of Pseudomonas species, and other psychrotrophs, produce a single type of monomeric 40—55 kDa neutral metalloprotease, with optimum pH of 6.

The dairy industry is facing constraints related to maintaining high quality and avoiding losses as a result of microbial spoilage. Pseudomonas single colonies were streaked onto Pseudomonas agar Oxoid Ltd. The study confirms the spoilage potential of strain in milk due to, at least in part, these two enzymes. Proteolytic activity among psychrotrophic bacteria isolated from refrigerated raw milk.

Proteolytic and lipolytic activity was measured as described above.

After heat treatment, samples were cooled immediately in an ice bath followed by the addition of 0. National Center for Biotechnology InformationU. The phenotypical characteristics indicate the isolate belongs to the genus Pseudomonas 11being mostly equivalent to Pseudomonas asplenii and Pseudomonas jenssenii The purification of AprX and LipM was important for the characterization of these spoilage enzymes and it would be interesting to use them to develop tools for improving their detection in poduction.


Molecular and phenotypic characterization bypdeudomonas Pseudomonas spp. Proteolytic activity was measured using azocasein Sigma, USA as a substrate following the protocol described by Santos et al. We amplified the apr X gene from all isolates using PCR.

Material and Methods Bacterial strains and plasmids The bacterial strains and plasmids used in bh study are listed in Table 1.

The lipM gene of P. Articles from Brazilian Journal of Microbiology are provided here courtesy of Elsevier. For these reasons, thermo-stable spoilage enzymes produced by a high number of psychrotrophic bacterial isolates from raw milk are of major concern to the dairy industry.

Hydrolytic potential of a psychrotrophic Pseudomonas isolated from refrigerated raw milk

Knaut observed that lipases from P. The detailed phenotypic results of Pseudomonas isolates were shown in Table 2 and Supplementary Table S1. Thermal inactivation of a heat-resistant lipase produced by the psychrotrophic bacterium Pseudomonas fluorescens. Quantitative and qualitative microbial analysis of raw milk reveals substantial diversity influenced by herd management practices. Rae of galactose and N -acetylglucosamine during the storage of UHT milk.

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Milk is usually stored at low temperatures for 2 to 5 days prior to heat treatment De Jonghe et al. The results reveal proteolytic activity of Pseudomonas spp. Peptidases secreted milm Pseudomonas during cold storage are heat-stable extracellular peptidases that can retain their activity after pasteurization or ultrahigh temperature UHT treatment Marchand et al.

Received Jul 10; Accepted Dec Support Center Support Center. Heterogeneity of heat-resistant proteases from milk Pseudomonas species. For this reason, in the future, whole genome sequencing of these isolates will be carried out to differentiate their spoilage potential.

Extracellular peptidase activity on milk agar was determined by the appearance of halo in the inoculated area. Lei YuanFaizan A. In this ensyme, lipase activity is generally higher in whole milk than in skimmed milk 6.


Abstract The storage and transportation of raw milk at low temperatures promote the growth of psychrotrophic bacteria and the production of thermo-stable enzymes, which pose great threats to the quality and shelf-life of dairy products.

Milk-deteriorating exoenzymes from Pseudomonas fluorescens isolated from refrigerated raw milk

Low storage temperature and short periods before processing within 48 h could reduce peptidase production of Pseudomonas spp. Isolates identified as Pseudomonas spp. Robinson New York, NY: The Supplementary Material for this article can be found online at: Affinity tags have become essential tools for the production of recombinant proteins in a wide variety of settings Waugh, Strains shown to produce heat-stable enzymes in the tests described above were selected for further thermal inactivation trials.

B are provided here courtesy of Zhejiang University Press. The spoilage potential of Pseudomonas has been extensively studied and those bypseuxomonas tend to produce proteases combined with lipases Capodifoglio et al. The 16S rDNA sequencing data indicated that the strain was taxonomically close to Pseudomonas species.

Phylogenetic affiliation of the pseudomonads based on 16S rRNA sequence. In addition, the genus Pseudomonas is considered as an important lipase producer, being sp exploited They mainly belong to the class of metallopeptidase EC 3. Diagnosing the cause of proteolysis in UHT milk.

The growth of the Pseudomonas is often associated with the production of extracellular enzymes e. Strain or plasmid Description Reference or source Strains E.