One-pot bioconversion of algae biomass into terpenes for advanced biofuels and bioproducts

Abstract

Under robust algae growth conditions, algal carbohydrates and proteins typically comprise up to ~80% of the ash-free dry weight of microalgae biomass. Therefore, production of algal biofuel through comprehensive utilization of all algal components and the addition of high energy density fuel compounds with “fit for purpose” properties or high-value bioproducts will both diminish the process cost and improve the overall process feasibility. In this study, we firstly demonstrated the concept of a “one-pot” bioconversion of algal carbohydrate and protein into value-added terpene compounds as advanced biofuel and high value bioproducts to improve the overall process feasibility through the development of engineered microbial consortium. The consortium for caryophyllene production yielded the highest titer of total terpene, up to 507.4mg/L, including 471mg/L of sesquiterpene, 36.4mg/L of monoterpene, and 124.4mg/L of caryophyllene on algal hydrolysate from Nannochloropsis sp. Additionally, the consortium expressing chamigrene synthase produced 187mg/L total terpene including 87mg/L of monoterpene, 100mg/L of sesquiterpene, and 62mg/L chamigrene on hydrolysate from benthic polyculture biomass. Compared to the yields of terpene extracted from plant tissue, both consortia increased the terpene yield about 3–40 times, which makes it a promising alternative pathway for terpene production.