Identification of heat stable protease of Klebsiella oxytoca isolated from raw milk

Tondo, Eduardo César; Lakus, Filipe R.; Oliveira, Fabrício Augusto de; Brandelli, Adriano

doi:10.1111/j.1472-765x.2003.01461.x

Cited by 29 publications

(27 citation statements)

References 13 publications

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“…Microbial proteases from psychrotrophic bacteria have been related to the coagulation or gelation of milk proteins, but few studies have demonstrated such defects by direct addition of proteases to milk samples (Datta and Deeth ; Tondo et al . ). UHT milk produced with low‐quality milk (psychrotrophic counts 4.7 log cfu/mL, photolytic activity 0.71 U/mL) showed an increase of 74.7% in soluble N values after 180 days versus 33.8% observed for high quality milk (3.2 log cfu/mL, 0.42 U/mL).…”

Section: Resultsmentioning

confidence: 97%

Investigation of Protease Production by P seudomonas fluorescens BJ-10 and Degradation on Milk Proteins

Zhang

Uluko

et al. 2015

Journal of Food Processing and Preservation

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The production of protease by Pseudomonas fluorescens BJ-10 and degradation on milk proteins were carried out. The results showed that the growth rate and protease activity in nutrient broth were lower than in milk. The maximum viable counts at both 6 and 28C in milk were approximately 10-11 log colony forming units (cfu)/mL. The highest protease activity in milk reached 227.99 U/mL. The protease preferentially degraded caseins in the following order κ-casein > β-casein > αs-casein and had low activity on whey proteins. Correlation analyses showed that protease activity was significantly (P < 0.01) related to viable counts. Regression equation was y = 31416.26-31415.33/(1 + 101.64 × −26.97), R 2 = 0.98. The protease showed a typical heat-stable behavior. After treatment at 130C for 3 min, more than 39.36 % activity remained. Crude protease caused coagulation of ultra high temperature milk after 5 days of storage at room temperature. We concluded that protease plays an important role in milk spoilage. PRACTICAL APPLICATIONThis work provides an alternative way for dairy processing enterprises to evaluate milk quality based on measured protease activity. Protease from psychrotrophic bacteria in milk plays an important role in milk spoilage after long periods of storage. In addition, dairy processing enterprises could reduce the storage time to avoid proteolysis in milk and consequent degradation of milk quality.

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Section: Resultsmentioning

confidence: 97%

Investigation of Protease Production by P seudomonas fluorescens BJ-10 and Degradation on Milk Proteins

Zhang

Uluko

et al. 2015

Journal of Food Processing and Preservation

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“…The cold-active proteases from different microorganisms vary in their thermostability and alkalistability [41,43,73,65,63,101,105,129,130,131]. High proteolytic activity at lower temperatures shown by cold-active proteases is important in the commercial usage of proteases, but their low thermal stability is a common drawback that hinders their use in industries.…”

Section: Enhancing Thermo-stability Of Cold-active Proteasesmentioning

confidence: 99%

Biotechnology of Cold-Active Proteases

Joshi

Satyanarayana

2013

Biology

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The bulk of Earth’s biosphere is cold (<5 °C) and inhabited by psychrophiles. Biocatalysts from psychrophilic organisms (psychrozymes) have attracted attention because of their application in the ongoing efforts to decrease energy consumption. Proteinases as a class represent the largest category of industrial enzymes. There has been an emphasis on employing cold-active proteases in detergents because this allows laundry operations at ambient temperatures. Proteases have been used in environmental bioremediation, food industry and molecular biology. In view of the present limited understanding and availability of cold-active proteases with diverse characteristics, it is essential to explore Earth’s surface more in search of an ideal cold-active protease. The understanding of molecular and mechanistic details of these proteases will open up new avenues to tailor proteases with the desired properties. A detailed account of the developments in the production and applications of cold-active proteases is presented in this review.

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“…Furthermore, their presence is not only linked to undesirable alteration in appearance and flavour, but residual activity of bacteria proteases can be related to gelation of milk and coagulation of milk proteins as well (Harwalker et al. 1993;Tondo et al. 2004).…”

Section: Introductionmentioning

confidence: 99%

Proteolytic activity among psychrotrophic bacteria isolated from refrigerated raw milk

Nörnberg

Friedrich

Weiss

et al. 2010

Int J of Dairy Tech

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Psychrotrophic bacteria were isolated from refrigerated raw milk from a processing plant in Southern Brazil. Psychrotrophic counts were between 4.9 and 7.8 log cfu ⁄ mL, and 5.3 to 7.2 log cfu ⁄ mL, for samples collected at the truck and the milk storage silo, respectively. Among the bacterial isolates, 90% were Gram-negative. Most strains presented low proteolytic activity, but strains of Burkholderia cepacia, Klebsiella oxytoca and Aeromonas sp. showed higher than 20 U ⁄ mL on azocasein as substrate. Crude proteases from selected strains were resistant to conventional heat treatments and caused coagulation of UHT milk after 5 days storage at room temperature.

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Identification of heat stable protease of Klebsiella oxytoca isolated from raw milk

Cited by 29 publications

References 13 publications

Investigation of Protease Production by P seudomonas fluorescens BJ-10 and Degradation on Milk Proteins

Investigation of Protease Production by P seudomonas fluorescens BJ-10 and Degradation on Milk Proteins

Biotechnology of Cold-Active Proteases

Proteolytic activity among psychrotrophic bacteria isolated from refrigerated raw milk

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