Abstract Urban trees and bushes generally require periodic pruning to address various issues such as visibility on roads and housing, public safety, and clearing power lines. However, managing the resulting biomass poses challenges like high handling costs, waste management overload, and the risk of fires and greenhouse gas emissions. At the same time, the growing demand for renewable products and eco-friendly processes is driving interest in using materials that are often discarded or have low added value. In this context, lignocellulosic biomass, such as tree pruning residues (branches, leaves, and bark), has emerged as a possible source of chemicals and materials that could replace the ones coming from fossil resources. Thus, taking the aforementioned into account, this work aimed to assess the potential of the woody part of tree pruning wastes of two tree-species (pine and cedar) for their valorisation through a multi-product biorefinery. For this aim, two valorisation pathways were studied. The first included a pre-treatment step (ethanol/water extraction) to recover extractives, followed by an organosolv delignification step. The second pathway focused only on organosolv delignification step. Using both approaches, high percentages of hemicellulose and lignin were successfully removed from the solid, resulting in cellulose-rich solids and lignin with high purity (> 95%). In this way, the effect of the pre-treatment was studied, and the resulting production yields together with the characteristics of the fractions were compared in order to assess possible applications. Introducing an additional stage not only enhanced the delignification process, but also led to another product of great commercial interest.
Morales et al. (Wed,) studied this question.