Efficient Production of δ-Guaiene, an Aroma Sesquiterpene Compound Accumulated in Agarwood, by Mevalonate Pathway-Engineered <i>Escherichia coli</i> Cells

Abstract

Mevalonate pathway for isoprenoid biosynthesis was constructed in <i>Escherichia coli</i> cells by the transformation with a gene cluster isolated from <i>Streptomyces</i> sp., and farnesyl diphosphate synthase and δ-guaiene synthase genes were coexpressed in this strain. This transformant was capable of liberating an appreciable amount of δ-guaiene, an aroma sesquiterpene compound accumulated in agarwood, and its concentration was elevated to more than 30 μg/ml culture by the incubation with mevalonolactone as an isoprene precursor in a nutrient-enriched Terrific broth. Coexpression of type 1 isopentenyl diphosphate isomerase plus acetoacetyl-CoA ligase genes also enhanced δ-guaiene production, and the concentration of the compound was approximately 38 - 42 μg/ml culture in the presence of mevalonolactone or lithium acetoacetate. These results clearly indicate that mevalonate pathway-engineered <i>E. coli</i> cells showed an appreciable δ-guaiene producing activity in the en- riched medium in the presence of appropriate isoprene precursors.