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.

Author: JoJodal Kigore
Country: Grenada
Language: English (Spanish)
Genre: Technology
Published (Last): 19 September 2016
Pages: 411
PDF File Size: 17.99 Mb
ePub File Size: 1.73 Mb
ISBN: 379-3-16890-636-5
Downloads: 13838
Price: Free* [*Free Regsitration Required]
Uploader: Gami

Proteolytic halos in the inoculated areas were indicative of proteolytic activity Scatamburlo et al. Nowadays, there is a great need for developing fast and reliable methods to detect spoilage enzymes directly from samples in order to determine the quality of lipsae that arrives at the dairy industry platform Datta and Deeth, In general, we found a large diversity of Pseudomonas species.

Find articles by Maurilio L. We evaluated the proteolytic activity of the isolates at all bypsfudomonas temperatures. Journal List Braz J Microbiol v. The bacterial strains and plasmids used in this study are listed in Table 1.

Psychrotrophic bacteria and proteolytic activity in refrigerated raw milk. The lipolytic activity of the predominant psychrotrophic bacteria is shown in Fig.

Login using

Support Center Support Center. Enzymes from isolates of Pseudomonas fluorescens involved in food spoilage. In total Pseudomonas isolates were confirmed. As hydrolytic enzymes from this bacterium are generally not inactivated by pasteurization or even by Ultra-High Temperature UHT treatment Griffiths et al. In this study, we confirmed these findings by showing that a number of Pseudomonas isolates could produce peptidases and exhibit proteolytic lipaxe under different storage temperatures.


Multiple sequence alignment of deduced protease AprX from P. Production, purification and partial characterization of the extracellular proteinase from Pseudomonas fluorescens 22F.

Biodiversity of culturable psychrotrophic microbiota in mi,k milk attributable to refrigeration mil, seasonality and their spoilage potential. The aims of the present work were i to isolate and identify Pseudomonas spp. Burger M, et al. The results of this study provide valuable data about the spoilage potential of bacterial strains in raw milk and the thermal resistance of the enzymes they produce.

To our knowledge, few studies have reported the spoilage potential of Flavobacterium.

There was a problem providing the content you requested

Identification of proteins by mass spectrometry P. The amount of P. Vector for the insertion of a Factor Xa Protease recognition site C-terminal of the 6xHis tag, T5 promoter, lac operator, ribosome binding site, ATG start codon, His tag sequence, multiple cloning sites, stop codons in all three reading frames, Col E1 origin of replication, Ap r. Heat-stable enzymes produced by psychrotrophic bacteria cannot be completely inactivated by thermal processing techniques and pose threats to the quality and shelf-life of dairy products.

Taken together, the extracellular peptidase activity and proteolytic activity data showed that the isolates could produce peptidases at different temperatures.

Species of Acinetobacter showed low proteolytic activity, and the lowest proteolytic activity was shown by Acinetobacter johnsonii a. Preliminary results showed the proteolytic potential of strain 1A4R during growth on skim milk agar plates, where prominent clearing zones were observed data not shown.


Heterogeneity of heat-resistant proteases from milk Pseudomonas species. Results for the Gibbs free energy Genthalpy Hand entropy S of thermal inactivation of enzymes have rarely been reported. The lipM gene of P. Phospholipase activity was found among the isolates belonging to the genera PseudomonasAcinetobacterFlavobacteriumSerratiaChryseobacteriumJanthinobacteriumand Aeromonasconsistent with their ability to cause sweet curdling defects or bitter cream in milk as a result of fat globule aggregation Titball, ; Vithanage et al.

Thermostability of proteases and lipases from a number of species of psychotrophic bacteria of dairy origin. Reducing the activity and limiting the secretion of heat-stable enzymes are scientific challenges.

The reaction mixture consisted of 0. Quantitative assessment of total lipolytic activity The lipolytic bypseudpmonas of the predominant psychrotrophic bacteria is shown in Fig. Comparison of identification systems for psychrotrophic bacteria isolated from raw bovine milk.

A commom type of protease produced by P. A wide variety of psychrotrophic bacteria can produce spoilage enzymes during late log or stationary growth phases Rajmohan et al. This genus is ubiquitous in nature and characterized by the tendency to tolerate dry conditions and multidrugs Gurung et al. Trans Inst Chem Eng.

Hydrolytic potential of a psychrotrophic Pseudomonas isolated from refrigerated raw milk

MU-butyrate zymogram of purified LipM. Lipase production by P.

Microbial contamination of raw milk is a crucial event determining the quality of the fluid milk and milk products.

Author: admin