Metabolic engineering for improved heterologous terpenoid biosynthesis

Terpenoids belong to the largest class of natural compounds and are produced in all living organisms. The isoprenoid skeleton is based on assembling of C5 building blocks, but the biosynthesis of a great variety of terpenoids ranging from monoterpenoids to polyterpenoids is not fully understood today. Terpenoids play a fundamental role in human nutrition, cosmetics, and medicine. In the past 20 years, many metabolic engineering efforts have been undertaken in plants but also in microorganisms to improve the production of various terpenoids like artemisinin and paclitaxel. Recently, inverse metabolic engineering and combinatorial biosynthesis as main strategies in synthetic biology have been applied to produce high-cost natural products like artemisinin and paclitaxel in heterologous microorganisms. Artemisinin is an important antimalarial drug and its demand can hardly been covered by plant cultivation and harvesting herbal material for extraction. Therefore additional biotechnological approaches have been applied to solve the problem of sufficient demand and cultivation independent of ecological conditions. Today most of the combinatorial biosynthesis studies have been carried out in E. coli or S. cerevisiae. This presentation describes the recent progresses made in metabolic engineering of the terpenoid pathway and the early artemsinin pathway in Xanthophyllomyces dendrorhous as new industrial host. X. dendrorhous has been developed as terpene factory because of its ability to biosynthesise high quantities of different terpenoid classes (e.g. mono-, di-, sesquiterpenoids). Early genes like amorphadiene synthase (ADS), Cyp450 71AV1 and DHAA Reductase (RED1) have been assembled and expressed successfully. With particular focus on fundamental aspects as knock out strategies, vector design, and metabolic profiling assembly of the early artemisinin biosynthesis towards dihydroartemisinic acid will be discussed.