17-14: Biosensor preparation of microfibrillated lignocellulose for analyzing enzymatic degradation behavior using Quartz crystal microbalance (QCM)

Biosensors were prepared from microfibrillated lignocellulose (MFLC) with different content of lignin and hemicellulose for real-time monitoring the enzymatic adsorption and degradation behavior using Quartz crystal microbalance (QCM). MFLCs were obtained by disk-milling followed by high pressure homogenizing of Hinoki crypress. Lignin and hemicelluloses contents were adjusted by sodium chlorite treatment and/or hydrothermal treatment under various reaction conditions. The centrifugal supernatants of thus-obtained MFLC water suspensions were spin-coated onto polyethyleneimine (PEI)-precoated gold QCM sensors. Film thickness was adjusted by changing MFLC concentration in the centrifugal suspensions, which is determined from its proportional correlation with UV absorbance of lignin. The zeta potential of MFLC and surface roughness of biosensor were also measured. The effect of different content of lignin and hemicellulose on enzymatic adsorption and degradation behavior was investigated using several enzyme systems, such as crude cellulase, CBH-I, and endoglucanase from Acremonium cellulolyticus. Chemical composition and kind of the used enzyme affected on enzymatic adsorption and degradation behavior. For example, MFLC biosensor with a high lignin content more than 26.4% showed a distinctive frequency and dissipation change in initial stage of enzyme adsorption, compared to pure microfibrillated cellulose. The biosensors obtained in this study showed the potential to evaluate the enzymatic reaction behavior of the real-pretreated product of lignocelluloses.