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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It is responsible for the spoilage of milk with activity on casein Dufour et al. It is important to stress that this work focused only on enzymes produced by planktonic cells. Effect of heat treatment for 60 min on lipolytic activity of purified LipM. For these poduction, thermo-stable spoilage enzymes produced by a high number of psychrotrophic bacterial isolates from raw milk are of major concern to the dairy industry.

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In contrast, Rajmohan et al. Boran R, Ugur A. This could be because of differences in the growth characterization of the isolates. Besides bypseuvomonas these spoilage enzymes, it is important to estimate the extent of degradation of milk components, and thus further improve enzymatic methods to access milk quality. There is a vast amount of scientific knowledge about the ability of psychrotrophic bacteria to produce spoilage enzymes, but no effective strategy has yet been presented to control this problem.


Multiple sequence alignment of deduced lipase LipM from P. The heat stability of enzymes originating from psychrotrophs is a limiting factor in maintaining the quality and shelf-life of dairy products.

The spoilage ability of Pseudomonas spp. Trans Inst Chem Eng. Support Center Support Center. Trends Food Sci Technol. Quantification of the proteolytic and lipolytic activity of microorganisms isolated from raw milk. Results Milk-deteriorating hydrolytic activities of P.

Open in a separate window. These results are in agreement with the findings of Liao and McCallus who observed that P.

Rheinheimera chironomi showed the lowest protease activity followed by A. Production, purification and partial characterization of the extracellular proteinase from Pseudomonas fluorescens 22F.

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Keratinolytic bacteria isolated from feather waste. Production of glycosidases by psychrotrophic bacteria. The pH optimum of AprX is between 6.

After heat treatment, samples were cooled immediately in an ice bath followed by the addition of 0. Molecular and phenotypic characterization of Pseudomonas spp.

A total isolates from all 87 samples were confirmed as Pseudomonasand were identified as belonging to 14 Pseudomonas species. Following a 5 days incubation on milk agar, extracellular peptidase activity was detected in Amplification of aprX gene and preparation for cloning in pQEXa. The bypseudomomas point for AprX was 4. In this work, a protease AprX and a lipase LipM produced by Pseudomonas fluorescensa highly proteolytic and lipolytic strain isolated from raw milk obtained from a Brazilian farm, have been purified and characterized.

Hydrolytic potential of a psychrotrophic Pseudomonas isolated from refrigerated raw milk

Quantitative assessment of total lipolytic activity Strains that showed positive produtcion production on screening medium were selected to quantify the total lipolytic activity. Kinetic parameters showed that lipases produced by A. Material and Methods Bacterial strains and plasmids The bacterial strains and plasmids used in this enzyke are listed in Table 1. Among psychrotrophic bacteria, genera of PseudomonasAcinetobacterFlavobacteriumChryseobacteriumand Serratia are the most frequently isolated from raw milk Vithanage et al.


Identification of proteins by mass spectrometry P. The D -values of proteases produced by S.

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

Pseudomonas single colonies were streaked onto Pseudomonas agar Oxoid Ltd. Microbiology Pt 2— Psychrotrophic bacterial populations in Chinese raw dairy milk. Each assay was performed in triplicate and with three replicates.

Extracellular protease activity of different Pseudomonas strains: 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 resulting cell bypseuvomonas were finally resuspended in lysis buffer 8 M urea, 0. This article has been cited by other articles in PMC.

The following primers were used: Characterization of pseudomonads isolated from decaying sporocarps of oyster mushroom. Data represent the average of duplicate experiments; D: Substrate solution was prepared with 1 mL of p NPP 0. Purification and properties of mil from Pseudomonas fluorescens strain 2D.

This genus is ubiquitous in nature and characterized by the tendency to tolerate dry conditions and multidrugs Gurung et al.