New ß-galactosidase producers with potential for prebiotic synthesis

• Autor(a) principal: Silvério, Sara Isabel Cruz
• Data de Publicação: 2018
• Outros Autores: Macedo, Eugénia A., Teixeira, J. A., Rodrigues, L. R.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/1822/49479
• topic: ß-galactosidase; fungal strains; lactulose; galacto-oligosaccharides; fructo-oligosaccharides; β-Galactosidase; Science & Technology

ß-galactosidases (EC 3.2.1.23) are interesting enzymes with potential application in the pharmaceutical and food industry. In this work, a screening study was carried out to identify new fungal sources of -galactosidase. A total of 50 fungi were evaluated using a chromogenic test performed in agar plates. The most promising microorganisms were validated as effective -galactosidase producers under submerged fermentation conditions. The crude -galactosidases were characterized regarding their optimal pH (3.0-5.5) and temperature (45-65 °C). All enzymes showed ability to synthesize lactose-based prebiotics, namely lactulose (maximal yield 3.3%) and a galacto-oligosaccharide (GOS) (maximal yield 20%). Additionally, some enzymatic extracts with fructosyltransferase activity allowed to produce other type of prebiotics, namely fructo-oligosaccharides (FOS). This work, reports for the first time the simultaneous synthesis of different mixtures of GOS (2-15% yield and 0.07-0.5 g/L·h-1 productivity) and FOS (4-30% yield and 0.1-1 g/L·h-1 productivity) by crude extracts exhibiting dual enzymatic activity.