Abstract:

Six β-glucosidase-producing fungi were screened through enrichment culture in martin medium, purification with
PDA medium, and color development with an esculin-based chromogenic medium. β-Glucosidase was extracted and purified
from the fermentation broth. Strain 10 revealed the highest β-glucosidase activity of 18.34 U/mL. The strain was identified
as Penicillium oxalicum by morphological and molecular methods. The β-glucosidase had optimal temperature of 55 ℃ and
was stable at 30, 40, and 50 ℃. The enzyme had optimal pH of 5 and could be stable between pH 5 and 6. Ag+ could activate
the β-glucosidase while Cu2+ could inhibit its activity.

Key words: Penicillium oxalicum, β-glucosidase, screening, enzymatic characteristics