α-Pinene

The pinene family of terpenes consists of two structural isomers, α- and β-pinene. Both exist as (+)- and (–)- enantiomers. Turpentine, obtained from pine trees, contains ≈60% α-pinene and ≈30% β-pinene. α-Pinene from North American trees is predominantly the (1R,5R)-(+)-enantiomer (shown), but most European α-pinene is (1S,5S)-(–). Recently, G. Bokinsky and J. D. Keasling genetically engineered Escherichia coli enzymes to convert switchgrass to sugars and then to pinene for jet fuel.