title: Mutagenesis of Aspergillus Oryzae IPT-301 to improve the production of β-Fructofuranosidase.
abstract: Aspergillus oryzae IPT-301, previously reported as a β-fructofuranosidase producing microorganism, was successfully mutated using UV irradiation at 253.7 nm followed by the screening of survivors resistant to certain stress conditions. Strains were first subjected to the β-fructofuranosidase activity assay using a portion from the colony grown in Petri dish as the enzyme source. Seven mutants with β-fructofuranosidase activity values relative to the parent culture between 140 - 190% were selected from survivors grown at temperature of 40ºC or 0.018% (w/v) sodium dodecyl sulfate concentration. They were cultivated on a rotary shaker to characterize mycelium and extracellular fructosyltransferase activities. Three mutants named IPT-745, IPT-746 and IPT-748 showed the highest amount of mycelium activity whose values increased 1.5 - 1.8 fold, compared with the parent strain. It was found that more than 55% of total enzyme activity (mycelium- plus extracellular- activity) from these strains was detected in the mycelium fraction. Only one mutant, IPT-747, exceeded the amount of extracellular enzyme exhibited by the parent strain (1.5 times). This mutant also showed the highest value of total fructosyltransferase activity.
authors.affiliation: Instituto Cubano de Investigaciones Azucareras-ICINAZ, Carretera al Central Manuel M. Prieto Km 2 ½, Boyeros Habana Cuba.
authors.forename: Beatriz Guilarte
authors.initials: BG
authors.lastname: Maresma
authors.forename: Boris Gutarra
authors.initials: BG
authors.lastname: Castillo
authors.forename: Rubén Cuervo
authors.initials: RC
authors.lastname: Fernández
authors.forename: Elda Sabino
authors.initials: ES
authors.lastname: da Silva
authors.forename: Alfredo Eduardo
authors.initials: AE
authors.lastname: Maiorano
authors.forename: Maria Filomena
authors.initials: MF
authors.lastname: de Andrade Rodrigues
keywords: Aspergillus oryzae; Fructooligosaccharides; Fructosyltransferase; Mutagenesis; UV irradiation; β-fructofuranosidase
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