Current means of production for plant-derived aroma compounds include chemical synthesis and extraction from plant material. Both methods are environmentally detrimental and relatively expensive: plant material is only seasonally available and only a small subset of the plant biomass produces the desired aroma compounds, while organic synthesis inevitably involves waste byproducts with a negative ecological impact. Benzenoids are a class of plant metabolites that includes a number of aroma compounds. This paper explores, for the first time, the feasibility of producing benzenoids in yeast. We present a method for the production of the phenylpropanoid methyl benzoate in Saccharomyces cerevisiae using benzoic acid as a substrate, by heterologous expression of Antirrhinum majus benzoic acid methyl transferase. Production was pH dependent with a maximal yield of approximately 50 μg of methyl benzoate per liter of culture per hour, and with linear kinetics over at least 24 h. In addition, we have analyzed two alternative expression vectors for the production of benzoic acid methyl transferase in S. cerevisiae: a constitutive triosephosphate isomerase promoter-based system was compared with a copper-inducible CUP1 promoter system. We find major differences in the amounts of methylbenzoate produced by these respective systems. Potential applications are discussed.
Bibliographical noteFunding Information:
This work was funded by Grant number 812-0393-04 from the Chief Scientist of the Israel Ministry of Agriculture and Rural Development to A.V., H.A, and D.W., by research grant number US-3437-03 from BARD to A.V., D.W., and N.D, and by the Hebrew University Intramural Research Fund Basic Project Award to H.A., D.W., and A.V.
- Benzoic acid
- Benzoic acid methyltransferase
- Methyl benzoate
- Saccharomyces cerevisiae