Lignocellulosic biomass degradation enzymes and characterization of cellulase and xylanase from Bosea sp. FBZP-16

One key factor in the design of enzymatic cocktails for the lignocellulosic biomass breakdown is the performance of bacteria . Bosea sp. FBZP-16, a high-performing bacterium strain producing different types of cellulases and hemicellulases, was evaluated for production of global (hemi)cellulolytic enzymes under different growth conditions. Different (hemi)cellulases were predominantly produced. On Sigmacell 101 and newspaper, the highest specific cellobiohydrolase activity was found with 830.8 U/mg and 1341.2 U/mg, respectively. Beechwood xylan revealed the highest β-xylosidase activity (1625.3 U/mg) consistent with the highest xylose release. Cultivation temperature of 30 and 35 °C produced most (hemi)cellulolytic enzymes between the 3rd and the 9th days of incubation at shaking frequencies from 150 up to 300 rpm, while the highest glucose and xylose yields were observed at 150 rpm. Respiration activity monitoring system analysis confirmed the potential of Bosea sp. FBPZ-16 to grow on xylan. The production of cellobiohydrolase and endoxylanase was further investigated using response surface methodology (RSM) and Box-Behnken matrix. The optimal conditions of the tested parameters were carbon source concentration (10 g/L), nitrogen source concentration (3 g/L), inoculum size (3 mL inoculum/100 mL media), and pH 7.0, where the maximal cellobiohydrolase production was found to be 2797 U/mg, which was close to the predicted activity of 2275.37 U/mg. The maximal endoxylanase production reached 60 U/mg, with a predicted value of 49.75 U/mg.