Volume 17, Issue 65 (fall 2013)                   jwss 2013, 17(65): 1-12 | Back to browse issues page

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H. Rahmani, A. Lakzian, A. R. Karimi Karouyeh, A. Halajnia. Effects of Time, Temperature, pH and Urease Concentration on Enzyme Adsorption and Activity of Vermiculite and Sepiolite. jwss 2013; 17 (65) :1-12
URL: http://jstnar.iut.ac.ir/article-1-1632-en.html
Ferdowsi University of Mashhad , soilsun65@yahoo.com
Abstract:   (19733 Views)
Urease is one of the most important enzymes in nitrogen cycle. The clay particles (with high surface area) play an important role in the stability of these protein compounds (enzymes) against various environmental factors. In order to examine the interactions between urease with sepiolite and vermiculite, three in vitro experiments were conducted separately in a completely randomized design. Two experiments were carried out with two replications. Treatments included six incubation times (0, 1, 2, 5, 10 and 20 days) and five levels of temperature (10, 20, 30, 40 and 50 ˚C). The third experiment was carried out in a factorial arrangement with two replications. Factors included three levels of pH (5, 7 and 9), and six-levels of enzyme concentrations (0.05, 0.25, 1, 5, 15 and 30 units). The results showed that the activity of adsorbed enzyme was more than free enzyme during the incubation time. The optimum temperatures for activity of free and adsorbed enzymes were 30 and 50 ˚C, respectively. It was concluded that enzyme adsorption on clay surfaces increases enzyme stability against environmental changes. Also, the results showed that the highest levels of urease adsorption on sepiolite and vermiculite occurred at pH 9 and 7, respectively. Adsorption isotherms of Enzyme showed that Vermiculite adsorbed urease with higher affinity compared to Sepiolite.
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Type of Study: Research | Subject: Ggeneral
Received: 2011/09/1 | Accepted: 2011/11/5 | Published: 2013/12/3

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