β-glucosidase from thermophilic fungus Thermoascus crustaceus: production and industrial potential

Abstract

Microbial β-glucosidases can be used in several industrial processes, including production of biofuels, functional foods, juices, and beverages. In the present work, production of β-glucosidase by solid state cultivation of the fungus Thermoascus crustaceus in a low-cost cultivation medium (comprising agroindustrial residues) was evaluated. The highest production of β-glucosidase, about 415.1 U/g substrate (or 41.51 U/mL), was obtained by cultivating the fungus in wheat bran with 70% humidity, during 96 h at 40°C. The enzymatic activity was optimum at pH 4.5 and 65°C. β-Glucosidase maintained its catalytic activity when incubated at a pH range of 4.0-8.0 and temperature of 30-55°C. The enzyme was strongly inhibited by glucose; even when the substrate and glucose concentrations were equal, the inhibition was not reversed, suggesting a noncompetitive inhibition. In the presence of up to 10% ethanol, β-glucosidase maintained its catalytic activity. In addition to β-glucosidase, the enzymatic extract showed activity of 36 U/g for endoglucanase, 256.2 U/g for xylanase, and 18.2 U/g for β-xylosidase. The results allow to conclude that the fungus T. crustaceus has considerable potential for production of β-glucosidase and xylanase when cultivated in agroindustrial residues, thereby reducing the cost of these biocatalysts.

Effects of Mixed Adding Crude Extracts of β-Glucosidases from Three Different Non-Saccharomyces Yeast Strains on the Quality of Cabernet Sauvignon Wines

“…In fact, the activity of β-glucosidase might be affected by the concentration of glucose or ethanol [ 14 , 15 ]. It was increased at low ethanol concentration by increasing the glycosyl transferase activity but it was decreased at high concentration of glucose (10%) or ethanol (≥10% v / v ) by altering its protein structure [ 16 , 17 , 18 , 19 ]. These results indicated the activity of SLY-4E, HX-13E and F2-24E was affected by a high concentration of glucose and ethanol but was relatively stable during wine fermentation.…”

Association of Fungi in the Intestine of Black Carp and Grass Carp Compared with their Cultured Water

“…Some species form symbiotic relationships with plants [57,58], while some are hosts themselves and beneft from the symbiotic bacteria in the process of growth and reproduction [59][60][61]. Both Termoascus and Termomyces are thermophilic fungi with unique survival ability and can secrete a variety of enzymes such as amylase and cellulase, which can provide nutrients for the growth of microorganisms [62,63].…”

Antifungal Activity of Ginger Rhizome Extract against Fusarium solani

“…Then, 2 mL of sodium carbonate (2 M) was added to stop the enzymatic reaction, and the absorbance of the released product at 410 nm was determined using a spectrophotometer. One unit of enzyme activity was defined as the amount of enzyme required to release 1 µmol of nitrophenol per minute of reaction [30].…”