Resumo

PAEZ, Gisela et al. Effect of lactose concentration over β-D-galactosidase production by Kluyveromyces marxianus ATCC 8554 in fed batch cultures. Rev. Soc. Ven. Microbiol. [online]. 2012, vol.32, n.1, pp.50-54. ISSN 1315-2556.

The effect of lactose concentration over β-D-galactosidase production by Kluyveromyces marxianus ATCC 8554 in fed batch cultures was studied using milk serum as substrate. The bioprocesses were carried out in triplicate at two lactose concentrations: 2.3% and 4.7%, pH 5 and a 35oC temperature in a Bioflo 4000 bioreactor. The enzyme extraction from the cells was done using 2% toluene. Enzymatic activity was determined evaluating the hydrolysis of o-nitrophenil-β-D-galactopiranoside (ONPG). With fed batch cultures and undiluted milk serum (4.7% lactose) we were able to obtain a higher biomass yield (Yx/s). The fed batch cultures allowed prolonging the production phase of the enzyme (509 µmol/L/10min) and maintain production for a longer period of time, higher than that mentioned for load cultures

Palavras-chave : fed batch lot; -D-galactosidase; lactose; Kiuyveromyces marxianus; serum.

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