Using mini-xylanosomes as a biotechnological tool for sisal fiber deconstruction and enzyme immobilization

Currently, there is an increasing demand for developing enzymatic blends that can efficiently deconstruct the hemicellulose present in plant fibers, since these fibers can be further employed to build new engineered materials. Sisal fibers are investigated as a source of cellulosic material to manufacture new materials, as reinforced fiber with plastic additives. A critical step to obtain the cellulosic matrix is the removal of hemicellulose present on these fibers. In the present study, a mini-xylanosome was tailored using a miniature version of C. thermocellum ’s scaffolding protein (two cohesins I domains and one carbohydrate-binding module family 3) and the xylanase XynZ. The designed xylanosome displayed higher thermal stability at 70 °C in comparison to the free form XynZ, 134 and 90 min of half-lives, respectively. Complexing xylanases into mini-xylanosomes or immobilizing complexes into cellulose did not reduce activity loss by tannic acid. Regarding sisal fiber deconstruction, the mini-xylanosome displayed better hydrolyzing capacity than the non-complexed xylanase, resulting in three times higher reducing sugars. Immobilized mini-xylanosome could be subjected to 72 h of reuse cycles at 50 and 60 °C, and at 70 °C for 48 h.