Potential of Poplar Bark Phytochemicals as Value-Added Co-products from the Wood and Cellulosic Bioethanol Industry

Development of high-valued products through an integrated biorefinery approach is essential for the revival of the Canadian forest industry. Utilization of tree bark is one such example with considerable potential. The bark of trees contains a reservoir of phytochemicals that could be harnessed as value-added co-products. The objective of this study was to identify, characterize, and seek commercial potential of phytochemicals present in poplar bark. Industrially harvested poplar bark (Populus tremuloides) was procured from Quebec. Water-soaked poplar bark was subjected to three steam-explosion treatments (treatments 1 to 3) using a steam-explosion reactor. During the experiment, extracts such as air purge, pre-steam purge, cooked purge, and pressed liquid were collected and subjected to compositional analysis. The results showed that the leftover bark residue even after the treatments was still fit for regular combustion for generating heat. Among the several identified phytochemicals (> 100), furfural, 5-HMF, benzoic acid, salicylic acid, and catechol can be obtained as bulk chemicals, and sakuranin present at 15.9 % (extracted with acetone) as a high-valued and fine chemical. Considering the increasing demand for plant-based ingredients, there exists enormous potential to utilize these phytochemicals in agro-pharmaceutical industries. Further end-use studies, however, are required to ascertain the true economic potential of poplar bark phytochemicals.