Paclitaxel: biosynthesis, production and future prospects

•Paclitaxel is a major anticancer drug produced by Taxus species.•Sustainable production of paclitaxel is problematic.•Typically, paclitaxel is produced via semi-synthesis.•Cambial meristematic cells provide an alternative production vehicle.•Microbial production hosts offer a potential future production route. Plants are capable of producing a wide variety of secondary metabolites which have a diverse range of functions that can be exploited for medicinal purposes; for example, paclitaxel is a major anti-cancer drug found in the bark of Taxus spp. There are however supply issues as the compound is only found at low concentrations (0.05%) within the plant. The complex paclitaxel biosynthetic pathway makes chemical synthesis non-commercially viable; therefore alternative biotechnological sources have been explored for production including heterologous expression systems and plant cell culture.