Large amounts of lignocellulosic biomass wastes and residues from industrial and agricultural processes are produced worldwide, however, are mostly used for energy purposes or discarded as residues. Only a few portion is valorized to produce high-value-added materials or bioethanol as more sustainable alternatives in comparison to their petroleum-based counterparts. In the adhesive industry, many efforts are being made to move toward a circular economy by developing bio-based adhesives from renewable resources, coupled to switching toxic solvents for water and improving the biodegradability. However, the low reactivity of lignocellulosic biomass needs still to be addressed for producing bio-based advanced materials. In this work, a novel biomass treatment combining hydrolytic enzymes and sonochemistry was applied on linseed wastes containing cellulose, hemicellulose, lignin, and proteins. The increased number of functional groups in the resulting biomass demonstrated the efficient fractioning with the sono-enzymatic system, which was higher than when using the two separated treatments (only ultrasounds or only enzymes). The obtained fractioned biomass was used to produce a bio-based solvent-free wood adhesive for replacing conventional petroleum-based adhesives. Taking advantage of the functional groups generated during the sono-enzymatic treatment, and using the oxidative enzyme laccase, natural low-molecular-weight phenolic compounds were grafted to the amino and phenolic groups from biomass, hence obtaining a highly cross-linked system. The adhesive obtained with the fractioned linseed presented higher tensile strength (up to 2.60 MPa) and improved rheological properties in comparison with the adhesive prepared with untreated linseed biomass. Moreover, the solid content in the formulation was increased from 30 to 60 % with the sono-enzymatic treatment, which is beneficial in many operational processes such as adhesive penetration in wood. Overall, a highly efficient biomass treatment combining hydrolytic enzymes and sonochemistry for the production of bio-based adhesives is presented.

Sono-enzymatic fractioning of biomass for the production of bio-based wood adhesive

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.