Optimization and partial purification of beta-galactosidase production by Aspergillus niger isolated from Brazilian soils using soybean residue

Abstract

β-Galactosidases are widely used for industrial applications. These enzymes could be used in reactions of lactose hydrolysis and transgalactosylation. The objective of this study was the production, purification, and characterization of an extracellular β-galactosidase from a filamentous fungus, Aspergillus niger. The enzyme production was optimized by a factorial design. Maximal β-galactosidase activity (24.64 U/mL) was found in the system containing 2% of a soybean residue (w/v) at initial pH 7.0, 28 °C, 120 rpm in 7 days. ANOVA of the optimization study indicated that the response data on temperature and pH were significant (p < 0.05). The regression equation indicated that the R 2 is 0.973. Ultrafiltration at a 100 and 30 kDa cutoff followed by gel filtration and anion exchange chromatography were carried out to purify the fungal β-galactosidase. SDS-PAGE revealed a protein with molecular weight of approximately 76 kDa. The partially purified enzyme showed an optimum temperature of 50 °C and optimum pH of 5.0, being stable under these conditions for 15 h. The enzyme was exposed to conditions approaching gastric pH and in pepsin’s presence, 80% of activity was preserved after 2 h. These results reveal a A. niger β-galactosidase obtained from residue with favorable characteristics for food industries.

β-Galactosidase-Producing Isolates in Mucoromycota: Screening, Enzyme Production, and Applications for Functional Oligosaccharide Synthesis

“…Some β-galactosidase producers have already been reported from the genera Rhizopus , Rhizomucor and Mucor [ 12 , 27 , 28 ], however, as far as we know, there were no data concerning Lichtheimia , Mortierella and Umbelopsis species. In filamentous fungi, the enzyme production of Aspergillus , Penicillium and Trichoderma species was studied in detail, and several producers have been identified during recent research studies [ 12 , 29 , 30 , 31 , 32 ]. Commercial β-galactosidases from filamentous fungal sources, especially from Aspergillus , were also previously prepared [ 33 ].…”

Production of β‐galactosidase by Trichoderma sp. through solid‐state fermentation targeting the recovery of galactooligosaccharides from whey cheese

“…The enzyme produced by A. niger was stable at 50°C for 1440 min (Martarello et al . 2019), while the β‐galactosidase from A. japonicus was completely inactivated when maintained at this temperature for 300 min (Saad 2004). β‐galactosidase secreted by A. tubingensis GR1 retained 49% of its initial activity after incubation at 55°C for 180 min (Raol et al .…”

“…2010), and A. foetidus (Martarello et al . 2019), which converted 55, 50 and 43·5% respectively of the lactose content into glucose and galactose. According to Prenosil et al .…”

“…2017; Martarello et al . 2019). β‐galactosidases from filamentous fungi exhibit optimal activity at acidic pH and temperatures ranging from 30 to 60°C, highlighting their potential for the hydrolysis of lactose present in acidic whey (Xavier et al .…”

“…2018; Martarello et al . 2019). In this context, the use of wheat bran as solid matrix is an important and interesting choice for this technology.…”