The saccharification of delignified corncob and Carolina poplar was carried out to study the stimulation of xylanases with or without CBMs to the hydrolysis of lignocellulosic biomass. In brief, 50 mg of delignified corncob or Carolina poplar powders with particle sizes under 75# mesh as well as 125 μL of commercial cellulase solution (2.5 mg/mL, C8546, Sigma-Aldrich) and of recombinant xylanase solution (25 μM) were loaded into a 5 mL tube. The reaction buffer (disodium hydrogen phosphate—citric acid buffer, pH 5.0, 200 mM) was then added to a final volume of 2.5 mL. Subsequently, the tubes were incubated in a shaker at 37 °C with a rotational speed of 200 rpm, and 10 μL of the supernatant were sampled at the 0th, 6th, 12th, 24th, 48th and 96th hour and then diluted to 150 μL for the determination of the reducing sugar concentration with DNS reagent. At the 96th hour, 100 μL of the supernatant was sampled and incubated in a boiling water bath for 20 min to stop the reaction. After filtration, the solution was loaded into a HPLC system (EClassic 3100, Elite) equipped with a MARS MOA 10u column and a refractive index detector to measure the glucose, xylose and arabinose concentration to calculate the cellulose and xylan conversion rates. The sulfuric acid solution (2.5 mM) was employed as mobile phase for separation at 60 °C with a flow rate of 0.6 mL/min.
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