초록
<P><B>Abstract</B></P> <P>β-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 β-galactosidase. A total of 50 fungi were evaluated using a chromogenic test performed in agar plates. The most promising microorganisms were validated as effective β-galactosidase producers under submerged fermentation conditions. The crude β-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<SUP>−1</SUP> productivity) and FOS (4–30% yield and 0.1–1 g/L·h<SUP>−1</SUP> productivity) by crude extracts exhibiting dual enzymatic activity.</P> <P><B>Highlights</B></P> <P> <UL> <LI> 50 fungi were screened to identify novel β-galactosidase producers. </LI> <LI> 8 fungi were validated as effective β-galactosidase producers. </LI> <LI> β-Galactosidases presented optimal pH (3.0–5.5) and optimal temperature (45–65 °C). </LI> <LI> Lactulose, GOS and FOS were produced using crude enzymatic extracts. </LI> <LI> Simultaneous production of mixtures of GOS and FOS was obtained for the first time. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>