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|Type:||Artigo de periódico|
|Title:||Production And Properties Of The Kluyveromyces Fragilis Nrrl Y-2415 β-galactosidase [producao E Propriedades De β-galactosidase De Kluyveromyces Fragilis Nrrl Y-2415]|
|Author:||Alvarez Nunes M.F.|
|Abstract:||Cheese whey permeate and deproteinised cheese whey by thermo-acid treatment can be used as growth medium by Kluyveromyces fragilis NRRL Y-2415 for β-galactosidase obtention. The supplementation of these media with (NH4)2SO4 (0.1%) and KH2PO4 (0.05%) increased cellular mass and β-galactosidase production. The enzyme extraction from cells by autolysis with potassium phosphote buffer (pH = 7.0, 36 °C), 2% chloroform, was faster when using 2% of toluene. Total enzyme activity depends of the cellular mass suspended in buffer. This enzyme presented optimum pH value at 6.6 to 6.8. Enzyme low stability was observed when maintained during one hour at different pH values. This fact means that the pH extraction must stay around the optimum value. The maximum activity was found at 30 to 37 ° C; at 50 °C the enzyme was inactivated. Microfiltration and ultrafiltration membranes were used on the initial purification steps. With a 0.08 mm membrane it was possible to separate cells and cells capsules, and with a 15.000 Daltons membrane concentrates up to 2.500 ONPG units per mL were obtained.|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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