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

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

doi:10.1186/s13068-017-0769-1

Christine E Sharp, Allyson L Brady + Show 4 more

Open Access

https://doi.org/10.1186/s13068-017-0769-1

Copy DOI

Journal: Biotechnology for Biofuels	Publication Date: Mar 29, 2017
Citations: 47	License type: open-access

Affiliation: University of Calgary

Abstract

BackgroundBioenergy 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.ResultsHere 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%).ConclusionFrequent harvesting and red light were the key factors that governed the assembly of a stable and productive microbial community.

Highlights

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
Initial phototrophic cultivation Duplicate flat panel laboratory bioreactors, fed with a high pH, high alkalinity medium, were inoculated individually with microbial mats from four soda lakes located in British Columbia, Canada [Last Chance Lake (LCL-M), Probe Lake (PL-M), Deer Lake (DL-M) and Goodenough Lake (GEL-M)]. 16S and 18S rRNA gene sequencing showed that these microbial mats harboured a diverse microbial community
Bacterial 16S ribosomal RNA amplicon libraries showed that biofilms cultivated from each of the four lakes were initially dominated by a mixture of three populations related to the cyanobacterium Phormidium kuetzingianum, and the bacillariophyta Nitzschia thermalis and Dickieia ulvacea (Fig. 1; Additional file 1: Table S1, Additional file 2: Table S2, Additional file 3: Table S3, Additional file 4: Table S4)

Summary

Introduction

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. Current BECCS strategies involve the growing of trees and crops that extract carbon dioxide (CO2) from the atmosphere, burning them in power plants, stripping the resultant CO2 from the waste gas and storage via C O2 injection into geological formations [3]. Operational costs are high due to the energy requirements of bubbling gas containing carbon dioxide through the open pond or photobioreactor. The use of high pH and alkalinity can improve transfer of CO2 into the culture medium and uncouples CO2 absorption and biological uptake, leading to lower energy requirements and costs [9,10,11].

Methods

Results

Discussion

Conclusion