Comparison of Enzymatic, Alkaline, and UV/H₂O₂Treatments for Extraction of Beetle-Infested Lodgepole Pine (BILP) and Aspen Bark Polyphenolic Extractives

Abstract

This paper describes the comparison of enzymatic, alkaline, and UV/H2O2 treatments for the extraction of beetle-infested lodgepole pine (BILP) and mixed aspen barks polyphenolic extractives. The concept of green polymers has become more appealing due to the presence of large volumes of processing residuals from the timber and pulp industries. This, in turn, supports the idea of developing new polymers based on bark extractives. Here, we used a chromatographic method to determine the chemical composition of some of the polyphenolic compounds in bark extractives and observed the effect of different extraction methods on extraction yield. Polyphenolic compounds separation was performed using HPLC in reverse-phase mode with an octadecylsilane (ODS), C18 column (3 μm particle size), and an UV detector. Detection wavelengths of 280, 310, and 370 nm were selected to allow better separation of each compound. The comparative studies and effects of enzymatic, alkaline, and UV/H2O2 treatments on extractives yield and component contents were investigated. UV/H2O2 treatment exhibited the highest yield with 54% of dry bark weight extracted and was found to degrade larger amounts of lignins/tannins than enzymatic and alkaline treatments. Conversely, enzymatic treatment was good for holocellulose.