Enhancing xylanases production by a new Amazon Forest strain of Aspergillus oryzae using solid-state fermentation under controlled operation conditions

The operation parameters used in solid-state fermentation (SSF) support the growth of filamentous fungi, which grow on solid substrates producing important metabolites such as proteases. The aim of this work is to obtain fungal proteases by SSF using the residues of a local brewery industry (barley bagasse and trub), that have high contents of proteins and soluble matter such as carbohydrates, vitamins, and mineral salts. The methodology includes the preparation of the residues, the screening of microorganisms, evaluation of the operation conditions for SSF using factorial design, purification and partial characterization of the protease. The results indicate that A. niger sp. UPT-03 isolated from the residue shows higher yields in terms of enzyme production (0.36 U gdm-1 h-1). The purification with DEAE-cellulose resulted in protease recovery with 30-fold of purification with a specific activity of 550 U mg protein-1. Higher proteolytic activity of purified enzyme was obtained at pH 5.5 and 55 ºC.

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CONVERSÃO DE DAIDZINA E GENISTINA DE SOJA POR β-GLICOSIDASE DE Aspergillus oryzae

Boletim do Centro de Pesquisa de Processamento de Alimentos ◽

10.5380/cep.v22i1.1189 ◽

2004 ◽

Vol 22 (1) ◽

Cited By ~ 2

Author(s):

CLAUDIO LIMA AGUIAR ◽

YONG KUN PARK

Keyword(s):

Solid State ◽

Enzymatic Activity ◽

Aspergillus Oryzae ◽

Solid State Fermentation ◽

Fungal Spores ◽

Product Formation ◽

Soy Flour ◽

Slight Reduction ◽

Total Conversion

Avaliou-se a capacidade de conversão de isoflavonas glicosiladas às suas formas agliconas pelo uso de β- glicosidase de Aspergillus oryzae ATCC 22786. A produção de daidzeína e genisteína foi acompanhada por 96 h de fermentação em estado sólido, usando-se farelo de soja e suspensão de esporos do fungo a 30ºC. Notou-se a conversão de glicosil-isoflavonas após 24 h e redução significativa na sua quantidade, depois de 48 h de fermentação. A atividade enzimática acompanhou a formação de produto até 72 h (0,2 UI/ mL), apresentando leve diminuição em 96 h (0,19 UI/ mL). Após 48 h obteve-se conversão total de daidzina e genistina, com formação de 551,1 e 17,2 µg/g de daidzeína e genisteína, respectivamente. A produção de genisteína, no entanto, mostrou-se significativamente superior em 24 h de fermentação (289,3 µg/g). Concluiuse que a β-glicosidase produzida por Aspergillus oryzae ATCC 22786 foi capaz de converter glicosilisoflavonas em agliconas por fermentação em estado sólido a 30ºC. CONVERSION OF SOY DAIDZEIN AND GENISTEIN BY β -GLUCOSIDASE OF Aspergillus oryzae Abstract The conversion capacity of glucoside isoflavones to aglycones by Aspergillus oryzae ATCC 2786 β-glucosidase was evaluated. The production of daidzein and genistein was observed for 96 h in solid state fermentation, by utilizing soy flour and a suspension of fungal spores at 30ºC. The conversion of glucoside isoflavones was noted after 24 h and a significant reduction in its quantity after 48 h of fermentation. The enzymatic activity followed the product formation until 72 h (0.2 UI/mL), showing a slight reduction in 96 h (0.19 UI/mL). After 48 h total conversion of daidzein and genistein was obtained, with formation of 551.1 and 17.2 µg/g of daidzein and genistein, respectively. The production of genistein, however, was significantly higher in 24 h of fermentation (289.3 µg/g). It was concluded that the produced β-glucosidase by Aspergillus oryzae was capable to convert glucoside isoflavones in to aglycones by solid state fermentation at 30ºC.

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