Work Package 3

Valorisation of waste wood fractions into high-value products

WP 3 aims at valorisation of the pretreated recycled wood fractions generated in WP 2. The applicability of cellulose and hemicellulose fractions for production of biochemicals by fermentation route will be screened (WP 3.1), lignin valorization as a tackifier in biobased hot-melt adhesives, e.g. for labels and fiber based packaging will be investigated (WP 3.2), and possibilities to utilise hemicellulose fractions after chemical modification as biobased surfactants will be studied (WP 3.3).

 Workpackage Leader

Tiina Liitiä

VTT

Work Package 3.1

Bioethanol production potential of recycled Wood

The potential of waste wood raw material and the studied pre-treatments for biotechnical fermentation processes will be evaluated. The hydrolysability of the pulps produced in WP 2 will be evaluated at lab scale by screening with commercial enzymes. For the selected samples, the enzyme cocktails based on commercial and precommercial products will be optimised. The suitability of selected hydrolysates for the production of biochemicals will be confirmed by yeast fermentation experiments to produce ethanol, in order to detect the effect of possible inhibiting compounds either originating from recycled wood feedstocks or formed in pre-treatments. A demonstration in larger scale will be carried out to produce hydrolysis lignin for WP 3.2.

Work Package 3.2

Lignin based hot melt adhesives

The aim is to valorise relatively low molecular weight side stream lignins as tackifiers or waxy components in biobased hot-melt or pressure sensitive adhesives. Completely biobased adhesive formulations are aimed at, and thus biodegradable cellulose acetate or PLA will be tested as cohesive providing polymers with lignin tackifiers. The effect of lignin source and pre-treatment process on structural features and gluing performance will be evaluated first. For comparison purposes a commercially available lignin will be used as a reference along the development work. To adjust the tackifying properties of lignins, various modification, fractionation and/or degradation methods for sufficient thermoplastisation and adhesion will be explored. Gluing experiments at lab scale will be performed to evaluate the tackiness and mechanical strength of the glue seams (to define adhesive/cohesive breakage). As reference, commercial hot melt adhesives will be used.

Work Package 3.3

Hemicellulose based surfactants

Possibility to utilise the side stream hemicelluloses produced in WP 2 as a hydrophilic component in biobased and biodegradable surfactants will be explored. Available hemicellulose fractions from organososolv and alkaline oxidation processes will be characterised, and the effect of DP (mono- vs. oligosaccharides) and degree of oxidation (alkaline oxidation vs. organosolv side-streams) on applicability as surfactants studied. Additional purification and fractionation methods will be developed. Chemical modification procedures to adjust the hydrophilic and lipophilic balance (HLB) of sugar based surfactants will be explored. To evaluate the applicability of sugar based surfactants, surface tension in aqueous solutions, critical micelle concentration and turbidity will be determined.