Exploring novel bacterial terpene synthases

Abstract

Terpenes are the largest class of natural products with extensive structural diversity and are widely used as pharmaceuticals, herbicides, flavourings, fragrances, and biofuels. While they have mostly been isolated from plants and fungi, the availability and analysis of bacterial genome sequence data indicates that bacteria also possess many putative terpene synthase genes. In this study, we further explore this potential for terpene synthase activity in bacteria. Twenty two potential class I terpene synthase genes (TSs) were selected to represent the full sequence diversity of bacterial synthase candidates and recombinantly expressed in E. coli. Terpene synthase activity was detected for 15 of these enzymes, and included mono-, sesqui-and diterpene synthase activities. A number of confirmed sesquiterpene synthases also exhibited promiscuous monoterpene synthase activity, suggesting that bacteria are potentially a richer source of monoterpene synthase activity then previously assumed. Several terpenoid products not previously detected in bacteria were identified, including aromandendrene, acora-3,7(14)-diene and longiborneol. Overall, we have identified promiscuous terpene synthases in bacteria and demonstrated that terpene synthases with substrate promiscuity are widely distributed in nature, forming a rich resource for engineering terpene biosynthetic pathways for biotechnology.

Discovery of an Abundance of Biosynthetic Gene Clusters in Shark Bay Microbial Mats

“…A recent study also found BGCs from Gammaproteobacteria were enriched in shallow sections of soil ( Sharrar et al, 2020 ). Gammaproteobacteria and Cyanobacteria are known prolific secondary metabolite producers and Bacteroidetes have previously been reported to encode for a range of bacteriocins thus supporting the relatively high count of BGCs at the surface layer ( Wang et al, 2014 ; Lopetuso et al, 2019 ; Reddy et al, 2020 ). The high distribution of BGCs at the microbial mat surface may also be attributed to microbial adaptations against harsh environmental conditions due to the surface layer being directly exposed to high UV radiation and desiccation stress ( Wong et al, 2018 ).…”

Comparing Sediment Microbiomes in Contaminated and Pristine Wetlands along the Coast of Yucatan

“…Today the bioproduction of retinoids is sought through the use of bacteria. Terpenoids, such as sesquiterpenoids and triterpenoids, due to their structural diversity have a wide range of industrial applications as pharmaceuticals, flavorings, fragrances, antimicrobials, pesticides, and antibiotics, among others [ 80 , 81 ]. Recent genome mining studies suggest that bacteria are a potentially much richer source of terpene synthases (TS), including enzymes from Cyanobacteria and Proteobacteria.…”

“…Recent genome mining studies suggest that bacteria are a potentially much richer source of terpene synthases (TS), including enzymes from Cyanobacteria and Proteobacteria. Actually new terpenoid products have been detected in bacterial species, including aromandendrene, acora-3.7 (14) -diene, and longiborneol [ 80 ], opening the possibility of finding in bacteria a source of new terpenoids with potential biotechnological use. Finally, our results indicate that conserved wetlands represent an invaluable source of molecules with potential applications in different industries such as pharmaceutical, cosmetic, agricultural, among others.…”

Alternative metabolic pathways and strategies to high-titre terpenoid production inEscherichia coli

“…235,236 There are few other examples of attempts to optimise titres using bacterial TPSs and modifying enzymes in E. coli (Table S1 †). However, several bacterial TPSs, CYPs and reducing partners have been expressed in E. coli to characterise product proles, [236][237][238][239][240][241] which further suggests that bacterial terpenoid biosynthesis genes express well in E. coli. Titres might be improved further by optimising precursor pathways and performing protein engineering studies.…”

“…245 Experimental validation has conrmed the activity of over 70 bacterial TPSs for two monoterpenoids (1,8-cineole and linalool), over 40 sesquiterpenoids and over 30 diterpenoids. 240,[245][246][247] Therefore, there are a growing number of bacterial TPS candidates that could be used for terpenoid production.…”