Lignocellulosic materials from agro-forestry sector represent a substantial renewable source of chemicals, energy and fuels that do not compete with food production and animal feed. In order for bio-based products to be competitive to oil-based ones, an integrative sustainable biorefinery strategy that maximizes the utilization of biomass needs to be developed. Lignocellulosic biomass consists mainly of the polysaccharides cellulose and hemicellulose and the phenolic polymer lignin, the latter giving plants a natural recalcitrance to biological degradation. Therefore, recovery of the components from lignocellulose requires pretreatment, as the removal of the lignin and hemicellulose allows hydrolytic reagents an improved access to cellulose in the subsequent hydrolysis steps. Among the green technologies, sonochemical methods are used in carbohydrate chemistry [1], not only for biomass pre-treatment, but also for the hydrolysis and cleavage of oligo- and polysaccharides. Indeed, ultrasound (US) provides a high energy input that destroys the lignocellulosic matrix at mild conditions [2], without generation of toxic byproducts or wastes streams. In this work, different US device were tested in order to compare the energy consumption, the yields of the solid residue and liquid fraction, and the generation of inhibitors. The parameters for the treatment with ultrasound were optimized in order to obtain an effective disruption of the lignocellulose matrix and increased accessibility for further processing steps. Different green solvents were investigated in terms of acoustic properties and lignin solvation capacity. In particular, γ-valerolactone and Natural Deep Eutectic Solvents (NADES) represent a sustainable alternative for the biomass fractionation, as they can be produced from the sugar fraction itself, leading to some material cycling in the process.
Ultrasonic treatment of lignocellulosic biomass for sugar production
TABASSO, Silvia;CALCIO GAUDINO, Emanuela;GRILLO, GIORGIO;CRAVOTTO, Giancarlo
2016-01-01
Abstract
Lignocellulosic materials from agro-forestry sector represent a substantial renewable source of chemicals, energy and fuels that do not compete with food production and animal feed. In order for bio-based products to be competitive to oil-based ones, an integrative sustainable biorefinery strategy that maximizes the utilization of biomass needs to be developed. Lignocellulosic biomass consists mainly of the polysaccharides cellulose and hemicellulose and the phenolic polymer lignin, the latter giving plants a natural recalcitrance to biological degradation. Therefore, recovery of the components from lignocellulose requires pretreatment, as the removal of the lignin and hemicellulose allows hydrolytic reagents an improved access to cellulose in the subsequent hydrolysis steps. Among the green technologies, sonochemical methods are used in carbohydrate chemistry [1], not only for biomass pre-treatment, but also for the hydrolysis and cleavage of oligo- and polysaccharides. Indeed, ultrasound (US) provides a high energy input that destroys the lignocellulosic matrix at mild conditions [2], without generation of toxic byproducts or wastes streams. In this work, different US device were tested in order to compare the energy consumption, the yields of the solid residue and liquid fraction, and the generation of inhibitors. The parameters for the treatment with ultrasound were optimized in order to obtain an effective disruption of the lignocellulose matrix and increased accessibility for further processing steps. Different green solvents were investigated in terms of acoustic properties and lignin solvation capacity. In particular, γ-valerolactone and Natural Deep Eutectic Solvents (NADES) represent a sustainable alternative for the biomass fractionation, as they can be produced from the sugar fraction itself, leading to some material cycling in the process.
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