Comparison of Enzymatic, Alkaline, and UV/H 2 O 2 Treatments for Extraction of Beetle-Infested Lodgepole Pine (BILP) and Aspen Bark Polyphenolic Extractives M. Ferhan,* N. Tanguy, N. Yan, and M. Sain Center for Biocomposites and Biomaterials Processing (CBBP), Faculty of Forestry, University of Toronto, Toronto, ON, Canada M5S 3B3 ABSTRACT: This paper describes the comparison of enzymatic, alkaline, and UV/H 2 O 2 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/H 2 O 2 treatments on extractives yield and component contents were investigated. UV/H 2 O 2 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. KEYWORDS: BILP, Mixed aspen bark, Polyphenolic extractives, HPLC, UV/H 2 O 2 , Enzymatic and alkaline treatments ■ INTRODUCTION Today, we are facing an environmental crisis, and its associated socio-ecological burden, mainly due to the extraction and processing of fossil fuels. Under these circumstances, it is urgent to reduce fossil resources consumption. As such, replacing petrochemical products with green biomaterials based on cost- effective renewable resources appears a viable solution. Petrochemical compounds such as phenol and its derivatives are produced in quantities over 10 million tons on an annual basis (essentialchemicalindustry.org/chemicals/phenol.html). There- fore, to alleviate environmental concerns, it is important to find new natural raw materials to produce polyphenolic compounds. One such raw material is woody biomass and bark, which is available in abundance as the byproduct from wood conversion industries. Bark, similar to wood, is composed of cellulose, hemicellulose, lignin, extractives, and ash. Compared to wood, bark contains higher amounts of phenolic extractives, such as lignan, hydrolyzable and condensed tannins, which have been of great interest to scientists and green technologists during the last two decades. The main idea of this study to produce value-added chemicals that are rich in phenolic structures and thus suitable for wood adhesives, 1 PF resins, 2 polyols, 3 polyurethane foams, 4 and Novolak resins. 5 In addition, the lower toxicity of bark-based phenolics as compared to pure phenol would expedite resin production. 6 In British Columbia, lodgepole pine (Pinus contorta var. latifolia) accounts for 24% of the total forest growing stock. 7 Large numbers of mature lodgepole pines have been damaged by the attack of the mountain pine beetle (Dendroctonus ponderosae) and its fungal associates. The scale of the mountain pine beetle attack in British Columbia is unprecedented. In 2010, the beetle attack had affected over 18 million hectares of forest and had killed 710 million m 3 of lodgepole pine. 8 Aspen (Populus tremuloides) is considered as a source species and is important for maintaining biodiversity in the western and boreal regions in North America. 9 It is one of the main timber sources in North America and in some Scandinavian and Baltic nations. 10 Aspen accounts for 39.5% of the growing stock volume of the forested land base in these countries, which is almost equal to the 42.1% of the stock that is attributable to all coniferous species. 11 In order to better understand the bark extraction process and to provide better direction for the application of bark extractives, it is important to explore and compare the effect of Received: June 17, 2013 Revised: October 15, 2013 Research Article pubs.acs.org/journal/ascecg © XXXX American Chemical Society A dx.doi.org/10.1021/sc400184f | ACS Sustainable Chem. Eng. XXXX, XXX, XXX-XXX