title: Use of highly alkaline conditions to improve cost-effectiveness of algal biotechnology.
abstract: Phototrophic microorganisms have been proposed as an alternative to capture carbon dioxide (CO2) and to produce biofuels and other valuable products. Low CO2 absorption rates, low volumetric productivities, and inefficient downstream processing, however, currently make algal biotechnology highly energy intensive, expensive, and not economically competitive to produce biofuels. This mini-review summarizes advances made regarding the cultivation of phototrophic microorganisms at highly alkaline conditions, as well as other innovations oriented toward reducing the energy input into the cultivation and processing stages. An evaluation, in terms of energy requirements and energy return on energy invested, is performed for an integrated high-pH, high-alkalinity growth process that uses biofilms. Performance in terms of productivity and expected energy return on energy invested is presented for this process and is compared to previously reported life cycle assessments (LCAs) for systems at near-neutral pH. The cultivation of alkaliphilic phototrophic microorganisms in biofilms is shown to have a significant potential to reduce both energy requirements and capital costs.
authors.affiliation: Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, AB, Canada.
authors.forename: Karen A
authors.initials: KA
authors.lastname: Canon-Rubio
authors.affiliation: Energy Bioengineering and Geomicrobiology Group, Department of Geoscience, University of Calgary, Calgary, AB, Canada.
authors.forename: Christine E
authors.initials: CE
authors.lastname: Sharp
authors.affiliation: Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, AB, Canada.
authors.forename: Joule
authors.initials: J
authors.lastname: Bergerson
authors.affiliation: Energy Bioengineering and Geomicrobiology Group, Department of Geoscience, University of Calgary, Calgary, AB, Canada.
authors.forename: Marc
authors.initials: M
authors.lastname: Strous
authors.affiliation: Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, AB, Canada. h.siegler@ucalgary.ca.
authors.forename: Hector
authors.initials: H
authors.lastname: De la Hoz Siegler
mesh_terms: D000468:Alkalies; D056804:Biofuels; D001709:Biotechnology / Q000191:economics* / Q000379:methods*; D002245:Carbon Dioxide / Q000378:metabolism*; D003362:Cost-Benefit Analysis; D004734:Energy Metabolism; D006863:Hydrogen-Ion Concentration; D058086:Microalgae / Q000235:genetics* / Q000378:metabolism*; D010788:Photosynthesis
chemical_list: D000468:Alkalies; D056804:Biofuels; D002245:Carbon Dioxide
keywords: Algal biofilms; Alkaline cultures; Alkaliphiles; Bioenergy; Biogas production; CO2 absorption