Production of α-pinene via the MVA pathways used in this study. Gene symbols and the enzymes they encode (all genes marked with gray arrows were from Enterococcus faecalis, all genes marked with white arrows were isolated from Saccharomyces cerevisiae and the gene marked with light gray arrows derived from Abies grandis or Pinus taeda). MVA pathway: MvaE, acetyl-CoA acetyltransferase /HMG- CoA reductase; MvaS, HMG-CoA synthase; ERG12, mevalonate kinase; ERG8, phosphomevalonate kinase; ERG19, mevalonate pyrophosphate decarboxylase; IDI1, IPP isomerase;GPPS2, Abies grandis geranyl diphosphate synthase was optimized to the preferred codon usage of E. coli; Pt30, Pinus taeda alpha-pinene synthase was optimized to the preferred codon usage of E. coli. Pathway intermediates. MVA pathway: A-CoA, acetyl-CoA; AA-CoA, acetoacetyl-CoA; HMG-CoA, hydroxymethylglutaryl-CoA; Mev-P, mevalonate 5-phosphate; Mev-PP, mevalonate pyrophosphate. IPP, isopentenyl pyrophosphate; DMAPP, dimethylallyl pyrophosphate; GPP, geranyl diphosphate.