A microbial process for the production of benzyl acetate

Benzyl acetate is a valuable aromatic ester compound with diverse applications in the flavor and fragrance industries. However, its current synthesis primarily relies on inefficient plant extraction methods or chemical/enzymatic processes that depend on non-renewable substrates. Here we report a sustainable approach to benzyl acetate production from d-glucose using metabolically engineered Escherichia coli strains. We explored both benzoic acid-dependent and -independent synthetic pathways by either dividing the pathway between upstream and downstream strain pairs or by introducing the complete pathway into single, integrated strains. In an optimized two-phase extractive fermentation process, a delayed co-culture of an upstream strain that converts d-glucose to benzoic acid and a downstream strain that transforms benzoic acid into benzyl acetate yielded 2,238.3 ± 171.9 mg l⁻¹ of benzyl acetate from d-glucose in 108 h (or 2,204.0 ± 192.2 mg l⁻¹ in 96 h). The economic competitiveness of the microbial process for sustainable benzyl acetate production was also assessed by techno-economic analysis.