Robust, high-productivity phototrophic carbon capture at high pH and alkalinity using natural microbial communities

Christine E Sharp; Sydney Urschel; Xiaoli Dong; Allyson L Brady; Greg F Slater; Marc Strous

doi:10.1186/s13068-017-0769-1

Robust, high-productivity phototrophic carbon capture at high pH and alkalinity using natural microbial communities

Biotechnol Biofuels. 2017 Mar 29:10:84. doi: 10.1186/s13068-017-0769-1. eCollection 2017.

Authors

Christine E Sharp¹, Sydney Urschel¹, Xiaoli Dong¹, Allyson L Brady², Greg F Slater², Marc Strous¹

Affiliations

¹ Department of Geosciences, University of Calgary, 2500 University Drive NW, EEEL 509, Calgary, AB T2N 1N4 Canada.
² School of Geography and Earth Science, McMaster University, Hamilton, ON Canada.

Abstract

Background: Bioenergy with carbon capture and storage (BECCS) has come to be seen as one of the most viable technologies to provide the negative carbon dioxide emissions needed to constrain global temperatures. In practice, algal biotechnology is the only form of BECCS that could be realized at scale without compromising food production. Current axenic algae cultivation systems lack robustness, are expensive and generally have marginal energy returns.

Results: Here it is shown that microbial communities sampled from alkaline soda lakes, grown as biofilms at high pH (up to 10) and high alkalinity (up to 0.5 kmol m^-3 NaHCO₃ and NaCO₃) display excellent (>1.0 kg m^-3 day^-1) and robust (>80 days) biomass productivity, at low projected overall costs. The most productive biofilms contained >100 different species and were dominated by a cyanobacterium closely related to Phormidium kuetzingianum (>60%).

Conclusion: Frequent harvesting and red light were the key factors that governed the assembly of a stable and productive microbial community.

Keywords: Algae biofuel; Biofilm; Microbial ecology; Mixed-community; Phormidium kuetzingianum.