Fast activated charcoal prepurification of Fusarium solaniβ-glucosidase for an efficient oleuropein bioconversion

ABSTRACT

Fungal β-glucosidases were extensively studied regarding their various potential biotechnology applications. Here, we report the selection of Fusarium solani strain producing high yield of β-glucosidase activity. The effect of some factors on β-glucosidase production was studied including: Initial pH, medium composition, concentration of carbon and nitrogen sources, and particle size of raw substrates. The optimal enzyme production was obtained with 4 units of pH. The highest β-glucosidase activity was produced on 4% wheat bran (WB) as raw carbon sources, reaching 5 U/mL. A positive correlation between WB particle size and the β-glucosidase production level was settled. The last one was enhanced to 13.60 U/mL in the presence of 0.5% (w/v) of ammonium sulfate. Interestingly, the activated charcoal was used as an inexpensive reagent enabling a rapid and efficient purification prior step that improved the enzyme-specific activity. Eventually, F. solani β-glucosidase acts efficiently during the bioconversion process of oleuropein. Indeed, 82.5% of oleuropein was deglycosylated after 1 hr at 40°C. Altogether, our data showed that the β-glucosidase of F. solani has a potential application to convert oleuropein to ameliorate food quality.

KEYWORDS:

• Activated charcoal
• bioconversion
• oleuropein
• prepurification
• wheat bran
• β-glucosidase

Acknowledgment

The authors would deeply thank Professor Raja Gargouri and Dr. Ines Belhaj for their helpful discussions, advice, and English proofreading. Sirine Choura is thanked for her technical help. This work was supported by grants from the Ministry of Higher Education and Scientific Research, Tunisia.