ABSTRACT
Better understanding through direct observation of the mechanisms involved in chemical and enzymatic hydrolysis of biomass is of great importance, to implement a substitute for the common cellulose standards. We report the hydrolysis of biomass, using exclusively the parenchyma, to isolate cellulose nanoplatelets using a less harsh pretreatment. Then, we show direct evidence of the effect of endoglucanase on the structure of cellulose nanoplatelets, finding that amorphous cellulose is exclusively digested, loosening the cellulose nanofibrils in the process. The analysis of micrographs demonstrates that when cellulose nanoplatelets are deposited on a silicon wafer, its thickness can be qualitatively measured by the interference color detected using an optical microscope. This finding facilitates further studies of mechanisms involved in lignin removal and cellulose nanofibrils production by specific enzymatic digestion.
Subject(s)
Agave/chemistry , Bacterial Proteins/chemistry , Cellulase/chemistry , Lignin/chemistry , Nanofibers/chemistry , Actinobacteria/chemistry , Actinobacteria/enzymology , Bacterial Proteins/isolation & purification , Biomass , Cellulase/isolation & purification , Humans , Hydrolysis , Lignin/isolation & purification , Nanofibers/ultrastructure , Sulfuric Acids/chemistryABSTRACT
Agave is recognized as a low recalcitrant material, which makes it a potential source to obtain nanocellulose. Aqueous dispersions (in water, H2O2, H2O2/H2SO4) of agave powder were heated at 120°C under vapor pressure (1kg/cm2). The resultant materials were observed with an optical microscope (OM), a laser scanning microscope (LSM) to obtain the thickness measurement and a scanning electron microscope (SEM) to observe morphology. Raman spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used to obtain the chemical structure. Cellulose nanoplatelets (CNPs) from Agave salmiana were successfully isolated under mild conditions. Physicochemical analysis indicates that lignin was removed in a single step oxidation with hydrogen peroxide in presence of sulfuric acid at low concentration (0.17M). The CNPs images revealed the presence of entangled cellulose nanofibrils (Ø≈14nm) along the nanoplatelets (thickness ≈80nm).
