Effect of lactose concentration on the grow kinetics of Kluyveromyces marxianus var. marxianus and production of b-D-galactosidase (E.C. 3.2.1.23)

Karelen Araujo, Gisela Páez, Zulay Mármol, José Ferrer, Eduardo Ramones, Cateryna Aiello Mazzarri, Marisela Rincón

Resumen


The effect of lactose concentration on the kinetics of growth of Kluyveromyces marxianus var. marxianus ATCC 8554 and production of enzyme b-D-galactosidase in cheese whey previously deproteinized was studied. The as says were carried out to lactose concentrations of 4.72%, 8.5%, 12.6% and to pH of 5 and temperature of 35°C, in a bioreactor Bioflo 4000 with a volume work of 3 liters. The enzymatic activity was determined evaluating hydrolysis of o-nitrophenil-b-D-galactopiranoside (ONPG) and the extraction of the enzyme from the cell was realized through ultrasound treatment. The maximum activity, 384.42 Ó 13.11 μmol ONP/L/5minutos was obtained in the non concentrated cheese whey (4.72%). The greater concentration of biomass and the highest specific speeds of growth were obtained in the non concentrated cheese whey (4.72%), and were 19.68 Ó 0.004 kg/m3 and 0.29 h”“1 Ó 0,006 respectively. The results showed a de crease in enzyme activity at high concentration of lactose, de spite the fact that this carbohydrate is normally used for induction of b-D-galactosidase activity.


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Universidad del Zulia /Venezuela/ Revista Técnica de la Facultad de Ingeniería/ revistatecnica@gmail.com /

p-ISSN: 0254-0770 / e-ISSN: 2477-9377 

 

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