Chemicals and biofuels from pine oleoresin

Coniferous trees are rich in chemical compounds such as terpenes, fats/fatty acids, waxes, tannins and phenolics, which function to protect the tree against insect pests and diseases, and as energy reserves. Compounds extractable with organic solvents typically comprise about 3 to 5 percent of total biomass on a whole tree dry basis, and may represent up to 25 percent in certain tree parts, such as heartwood in the inner basal portion of the stem and roots. Trees may develop higher levels or altered profiles of extractives when subjected to stressors, including mechanical injury, water-deficit, pest attack, or atmospheric pollutants. Terpenes are a large group of compounds having molecular formulas that are multiples of C5H8. Oleoresin is an important natural product that is a mixture of resins (diterpene acids) that are normally a solid material at room temperature, and volatile essential oils (monoand sesquiterpenes) that serve as a solvent to maintain the oleoresin in a fluid state. Oleoresin is synthesized by the thin-walled epithelial cells within the wood parenchyma tissue. In pines and firs, these structures are organized as a network of interconnected radial and longitudinal ducts which store oleoresin at elevated pressure and transport it to injury sites. Oleoresin is especially abundant in certain pines, such as Pinus elliottii, P. palustris, P. taeda, and P. ponderosa.