Discovery and Synthesis of Terpenoids Using Synthetic Biology

Terpenoids, or isoprenoids, constitute possibly the largest group of natural products (>70,000). Structural diversity of terpenoids contributes to wide applications ranging from pharmaceuticals (e.g., artemisinin), nutraceuticals (e.g., astaxanthin), flavors and fragrances (e.g., linalool), polymer molecules (e.g., isoprene) and biofuels (e.g., farnesene). Unlike plant terpenes that are well studied, most fungal terpenes and their synthases remain largely untapped. Our group has thus developed an integrated platform for discovery of novel fungal terpene synthases (TPSs). Coupling bioinformatics and experiments (SPME-GCMS), we have successfully predicted several unique clusters of putative isofunctional TPSs (e.g. protoilludene, viridiflorol) and validated by experiments.

In addition, we also developed a multidimensional heuristic process (MHP) to efficiently synthesize these molecules in Escherichia coli. Built on modular metabolic engineering methods, MHP is a focused and systematic approach to optimize the performance of biosynthetic pathways, especially effective on complex systems (>10 genes). MHP adopts ‘modular design’ that significantly reduces experimental workload yet without losing the flexibility by simultaneously control different functional dimensions (transcription, translation and enzymes). As a proof-of-concept, we effectively enhanced the production of the 15-step heterologous biosynthetic route of the nutraceutical astaxanthin at (320 mg/L, C40), as well as different isoprenoid fragrance molecules, linalool (0.5 g/L, C10), nerolidol (~4 g/L, C15) and viridiflorol (~1.2 g/L in flasks, C15), apocarotenoid fragrance molecules α-ionone (0.5 g/L, C13) and β-ionone (0.5 g/L, C13). Evidently, MHP is generally applicable for different metabolic pathways and products.

Reference:

1. ZHANG, C., Seow, V. Y., Chen, X. & Too, H.-P. Multidimensional heuristic process for high-yield production of astaxanthin and fragrance molecules in Escherichia coli. Nat Commun 9, 1858 (2018).
2. ZHANG, C., Chen, X., Lindley, N. D. & Too, H.-P. A ‘plug-n-play’ modular metabolic system for the production of apocarotenoids. Biotechnol. Bioeng. 115, 174–183 (2018).
3. ZHANG, C. Progress in Carotenoid Research, Chapter 5 (InTech, 2018). doi:10.5772/intechopen.79061