Fermentable Liquid Energy Carriers by Microwave-Assisted Hydrothermal Depolymerisation of Several Biomass Carbohydrates

摘要

Microwave-assisted hydrothermal depolymerisation allows the conversion of the carbohydrate content of biomass into fermentable sugar-rich aqueous solutions. For the development and commercialisation of this route, it is very important to achieve an optimum control of the process in order to strike a good compromise between sugar production and sugar degradation, as the latter leads to the formation of fermentation inhibitors such as aldehydes, carboxylic acids, ketones and furans. Microwave heating is based on the high frequency rotation of polar molecules, which produces a quicker and higher heating of the species with high polarity. As lignin has a lower polarity than cellulose and hemicellulose, it is less active during microwave heating. This allows the solubilisation of the carbohydrate content of the biomass without significantly solubilising the lignin fraction. This minimises the presence of lignin-derived inhibitors in the hydrolysate. In addition, as water is highly effective in microwave energy absorption, the combination of hydrothermal conditions together with microwave-assisted heating might result into a very promising technology to achieve a selective and controllable production of saccharide-rich aqueous solution from biomass.