EUBCE 2026 - George PHILIPPIDIS - Enhancing Salinity Tolerance and Lipid Productivity of Extremophilic Micractinium Sp. Using Adaptive Laboratory Evolution and Random Mutagenesis

Enhancing Salinity Tolerance and Lipid Productivity of Extremophilic Micractinium Sp. Using Adaptive Laboratory Evolution and Random Mutagenesis

Short Introductive summary

Microalgae represent a promising bioresource to mitigate greenhouse gas emissions and perform wastewater treatment, while concurrently generating value-added products, like sustainable aviation fuel and nutraceuticals. However, large-scale cultivation is constrained by high freshwater consumption and low lipid yield. Two extremophilic freshwater Micractinium sp. growing at pH 3.5 and pH 10.0, respectively, which were isolated by our team in the Amazon region of Ecuador, were subjected to adaptive laboratory evolution to elicit genetic modifications that lead to high salinity tolerance, thus reducing the need for freshwater in cultivation. Both strains successfully underwent progressive adaptation to 70% seawater, while maintaining their growth rate at extreme pH. To boost the lipid productivity of the adapted strains, random mutagenesis with ultraviolet (UV) light was employed. After screening 75 colonies, we isolated two mutants that exhibited the highest lipid content of 23.8% and 21.4%, respectively, which were significantly higher than the wildtype’s 18.3%. The mutants were cultivated in a 2-liter photobioreactor in saline media to demonstrate strain robustness and scalability.

P. Slick, University of South Florida, Tampa, USA
C. Tran, University of South Florida, Tampa, USA
D. Dorta, University of South Florida, Tampa, USA
E. Lo, University of South Florida, Tampa, USA
N. Arora, Skidmore College, Saratoga, USA
V. Ochoa-Herrera, Universidad San Francisco de Quito, ECUADOR
G.P. Philippidis, University of South Florida, Tampa, USA