Lignocellulosic Film as a Valid Tool to Investigate Inhibitions to Cellulose Enzymatic Hydrolysis

Abstract

The complex supramolecular structure of lignocellulose makes it difficult to clarify the recalcitrance to enzymatic digestibility. As an extensively used model mimicking the plant cell wall, assembled lignocellulosic film was applied to investigate inhibition factors of enzymatic hydrolysis for the first time. Xylan was deposited and then a model lignin compound was synthesized to equip bacterial cellulose films. Scanning electron microscopy and surface contact angle analyses revealed that lignin inhibited enzymatic hydrolysis by reducing cellulase accessibility to the cellulose surface. Moreover, xylan showed a good correlation (R2 = 0.969) with the decreased cellulose conversion, although xylan itself did not display inhibitions. The component and surface analyses revealed that xylan enhanced lignin formation on the cellulose surface, and thus increased lignin inhibition. These results highlighted the validity of lignocellulosic films in elucidating inhibitions of cellulose enzymatic hydrolysis. The research could thus open a new avenue for the mechanistic study of the recalcitrance of lignocellulose to enzymatic hydrolysis.