A sustainable method for carbon sequestration using algae (Chlamydomonas reinhardtii) deficient in phosphate and nitrogen uptake

Background/Question/Methods: Carbon dioxide levels have been rising rapidly. Algae are single celled protists with highly efficient CO₂ uptake mechanisms. Algae yield 2-10x more biomass vs terrestrial plants and can grow nearly anywhere. Large scale CO₂ sequestration is not yet sustainable due to high amounts of nitrogen (N) and phosphate (P) needed for growth media. Objective: was to see if mutant strains of algae could be created that were deficient in N/P uptake but produced as much biomass as control strains. To conduct the experiment, I created two new mutant strains of C reinhardtii using ultraviolet light (2.2-3K J/m2) and natural selection with lower concentrations of N/P based Sueoka’s media (20-80% normal). Biomass was compared to wild-type control (CC-125) using direct counts, optical density and dry weight. Mean doubling time also was calculated.

Results/Conclusions: Mean doubling time was 20 and 25 hrs in the Low N and Low N/P strains respectively (vs 66 hrs in control). Dry weight and optical density measurements had fair-poor correlation to cell counts (R² = 0.1 and 0.6) respectively. Using direct counts, growth rates of mutant strains of Low N and Low N/P cultures were not significantly different from control (P = 0.37 and 0.70) respectively. Growth was best in 80%N/80%P and 80%N/60%P media. My new strains of algae were able to grow as well as wild-type control while using 20-40% less N and P. Implications for ecology: it has been estimated that algae could capture 95 million tons CO²/ha/year. Using my strains an extra 19-38 million tons CO₂/ha could be captured/year. This may make long-term CO₂ sequestration using algae more sustainable.

See more of: Genetics And Molecular Techniques
See more of: Contributed Posters

Previous Abstract | Next Abstract >>