β glucosidase from aspergillus niger

Rice straw was procured from a local paddy field in the central part of Thailand. The moisture content from the collected biomass was removed by drying it in a hot-air oven (WOF-50, Daihan Scientific, Gangwon-do, Korea) at 80 °C until a constant weight was obtained. Then, the dried rice straw sample was reduced in size using a household blender and sieved through a 20-mesh-sized aluminum sieve to obtain a uniform particle size. The biomass composition of the rice straw samples was analyzed by following the Van Soest protocol [28 (link)].
The 1-ethyl-3-methylimidazolium acetate (EMIM-Ac) and commercial cellulase enzyme, CelluClast 1.5 L, produced by Trichoderma reesei used in this study was bought from Sigma-Aldrich (St. Louis, MO, USA). The enzyme β-glucosidase from Aspergillus niger was obtained from Megazyme (Wicklow, Ireland). The 3,5-Dinitrosalicyclic acid used in reducing sugar determination was purchased from Alfa Aesar (Heysham, UK). The other solvents used in this study were obtained from RCI Labscan (Bangkok, Thailand).

TtLPMO9E was donated by Novozymes A/S (Bagsværd, Denmark). The TtLPMO9E concentration was determined by absorbance at 280 nm using a molar extinction coefficient of 58,120 M⁻¹ cm⁻¹. Novozym 188 was obtained from Novozymes A/S (Bagsværd, Denmark). β-glucosidase from Aspergillus niger and cellobiohydrolase I (CBHI) from Trichoderma longibrachiatum were purchased from Megazyme with a specified activity of 40 U ml⁻¹ and a concentration of 10 mg ml⁻¹, respectively.

Complete T. reesei cellulase was from fungal culture (strain SVG17) on wheat straw. TrCBH I was purified from the cellulase mixture using a reported ion exchange protocol [76 (link)]. Serum albumin fraction V (BSA) was bought from Roth (Karlsruhe, Germany), β-glucosidase from Aspergillus niger and β-xylanase M1 from T. viride were obtained from Megazyme International (Wicklow, Ireland). Avicel PH-101 and lignin (alkali, low sulfonate content) were obtained from Sigma-Aldrich (St. Louis, MO, USA), barley β-glucan (high viscosity > 100 cST) from Megazyme International (Wicklow, Ireland), birch xylan from Roth (Karlsruhe, Germany), cellotetraose and 4-methylumbelliferyl-β-d-cellobioside from Carbosynth (Compton, UK). CNC was prepared from Whatman^® qualitative filter paper (Sigma-Aldrich, St. Louis, MO, USA) using H₂SO₄ according to Lu et al. [63 (link)]. Amorphous thin film cellulose (ATFC) was prepared from trimethylsilyl cellulose by a reported procedure [57 (link)].