Construction of an Artificial Microbial Consortium for Green Production of (−)-Ambroxide

(−)-Ambroxide is a key ingredient of the fauna natural perfume ambergris, which is currently mainly supplied by the semi-synthetic route using plant-extracted sclareol as the raw material. Biosynthesis of (−)-ambradiol as the direct precursor of ambroxide holds promise for addressing the energy and environmental concerns in this semi-synthetic process. Due to the lack of the natural producer of ambradiol from glucose and the unrevealed metabolic pathway from sclareol to ambradiol, we divided the whole pathway into two modules and built an artificial microbial consortium using engineered sclareol-producing Saccharomyces cerevisiae and natural sclareol-converting Hyphozyma roseonigra ATCC 20624. S. cerevisiae strain YN42 was constructed by assembly and optimization of the plant-sourced sclareol synthetic pathway, producing 357.3 mg L^–1 of sclareol in shake flasks. After validating the capability of ATCC 20624 in converting sclareol to ambradiol, an artificial microbial consortium was established for (−)-ambradiol production. In the optimized co-culture system, up to 644.2 mg L^–1 of ambradiol was produced from glucose. By promoting the transmembrane transportation of sclareol via adding 2-hydroxypropyl-β-CD, a simplified induction-free co-culture system was constructed, producing 493.1 mg L^–1 of ambradiol in shake flasks. This work provides an example for the biosynthesis of natural products with only a partially characterized pathway and points to a new production route of (−)-ambroxide.