Effect of enzymatic pretreatment of sugarcane bagasse with recombinant hemicellulases and esterase prior to the application of the cellobiohydrolase CBH I Megazyme

The polysaccharides in the primary plant cell wall are a renewable energy source for biofuel production. However, these polysaccharides are not readily available for bioconversion, and large enzyme sets are required to deconstruct them. Here, we aimed to improve the glucan conversion using recombinant hemicellulases and esterase as a treatment in exploded and sugarcane bagasses (SCB), followed by the addition of commercial CBH I to prevent its inhibition by hemicellulases products. A high secretion level of the recombinant enzymes was observed on SDS-PAGE. The highest activities were verified at a temperature and pH ranging from 40 to 55 degrees C and 4.5 to 6.0, respectively. The released reducing sugar analysis showed that all enzymes act better on SCB, with xylanase C (XynC) presenting the best activity (0.54 U/mg of protein). The high-performance liquid chromatography (HPLC) analysis demonstrated that 24 h of pretreatment was enough to reach maximum glucan conversion. The best synergy was achieved between XynC and CBH I on SCB, 1.4%. All results showed that the enzymes acted better on SCB, which can be related to the biomass composition and its molecular structure. The enzymatic pretreatment of SCB with XynC was essential to improve the glucan conversion by CBH I.