Supplying plant natural products by yeast cell factories

Plant natural products have been used for centuries to treat human illnesses, as recreational substances, and as flavouring and colouring agents in our food. Nowadays commercial scale manufacturing of plant natural products using extraction from natural resources or chemical synthesis pose challenges for environmental sustainability, such as species overexploitation. Bio-based synthesis of plant natural products in microbial cell factories can offer an attractive alternative as these processes reduce the use of natural plant resources and instead rely on renewable feedstocks as raw materials. Here, we review the most recent developments on sustainable supply of plant natural products by bio-based synthesis in yeast, with special focus on newly discovered and implemented plant natural product biosynthetic pathways, approaches for chemical diversification of natural products, and optimization of platform yeast cell factories. From this we discuss environmental considerations and the main challenges towards sustainable and robust microbial production of plant natural products based on fermentation.