Energy Potential of Urban Tree Pruning Waste

Abstract Background Large urban centers, such as São Paulo, have green areas interspersed with asphalt and buildings, requiring periodic maintenance to avoid issues with electrical networks. Urban tree management generates tons of pruning waste that is often deposited in landfills. Therefore, it is essential to discard these residues sustainably by composting and reusing the material to generate bioenergy and value-added products that support a circular economy. Methods This study aimed to evaluate the biomass potential of pruning tree waste through a composting system by characterizing the cell wall composition, starch, lignin, and saccharification capacity. Results The fermentable sugars in pruning tree waste are degraded during the composting process; however, the levels of starch, galactose, xylose, and arabinose are maintained during the first weeks of composting. Conclusions These sugars can be utilized for energy production and contribute to the saccharification capacity. Throughout the 32-week composting process, lignin is not degraded; however, the decrease in other sugars in the biomass increases the proportion of lignin, suggesting opportunities for the use of thermal energy and green chemistry.