The triterpenoids are one of the largest and most structurally complex plant natural products. They are widespread in the Plant Kingdom and have a huge array of structures and numerous associated biological activities. They have important roles in plant defence and signalling. They are also exploited by humans as food supplements, drugs and cosmetics across various sectors. In the past the discovery and production of triterpenoids has relied mainly on isolation from extracts of natural sources and subsequent structural elucidation and chemical modification. These methods suffer from low efficiency and high cost, and are not environmentally sustainable. We herein propose a greener and more sustainable but as yet largely unexplored synthetic biology-based approach that involves genome mining and metabolic engineering to synthesise structural variants of triterpenoids, with a view to discovering novel structures with biological activities for various application prospects in a rapid manner. This project will also shed new light on the biosynthetic pathways of triterpenoids by uncovering new genes and enzymes and will open up opportunities for production of important triterpenoids via further metabolic manipulations in plant or microbial ‘green factories’.