The enzymatic characters of heterologous expressed novel β-1, 4-glucosidase originated from Aspergillus fresenii.

β-1, 4-glucosidases generate glucose from cellobiose and oligosaccharides, enhancing the productivity in biorefinery and the bioconversion process as well as the nutritional value in food and feed. With the high-throughput sequencing technique, a novel β-1, 4-glucosidase, named bgl T2, containing 861 amino acid residues, was found from Aspergillus fresenii. bgl T2 belongs to the glycosyl hydrolase (GH) family 3. The bgl T2 that expressed by Komagataella phaffii X33 presented the highest activity at 55 °C and pH 5.5. The half-lives of bgl T2 under 50 °C, 55 °C, 60 °C, and 65 °C were 9 min 36 s, 4 min 22 s, 117 s, and 68 s, respectively. The bgl T2 was stable between pH 3.0 to pH 8.0. The Michaelis constant (K m) and the theoretical maximum rate (V max) of bgl T2 were 0.0007 mol/L and 9 × 10-8 mol/L/s, respectively. In a 5 L fermentation vessel, the recombinant K.phaffii X33 could yield a β-1, 4-glucosidase activity of 4.45 U/mL after 96 h methanol inducement. As an important member of cellulases, the novel bgl T2 might contribute to bioenergy, food processing, feed enrichment, and nutritional study, etc. This study also developed a path to obtain new enzymes depending on high-throughput sequencing technique. © King Abdulaziz City for Science and Technology 2020.