title: Using carbon dioxide to maintain an elevated oleaginous microalga concentration in mixed-culture photo-bioreactors.
abstract: Microbial contamination of growth reactors is a major concern for microalgal biofuel production. In this study, the oleaginous, CO2-tolerant microalga Scenedesmus dimorphus was combined with a wastewater-derived microbial community and grown in replicated sequencing batch photobioreactors. The reactors were sparged with either ambient air or 20% v/v CO2. In the initial growth cycles, air and the 20% CO2 reactors were similar in terms of growth and microbial community structure. Beyond the fourth growth cycle, however, the ambient air reactors had larger decreases in cell density and growth rate, and increases in species richness and non-algal microorganisms compared to the 20% CO2 reactors. Both qPCR and rDNA sequence analyses demonstrated a greater loss in S. dimorphus enrichment in the ambient-air reactors compared to the 20% CO2 reactors. These results demonstrate that environmental parameters can be used to delay the adverse impacts of microbial contamination in open, mixed-culture microalgae bioreactors.
authors.affiliation: Department of Chemical and Environmental Engineering, Yale University, New Haven, CT 06520, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Giannetto
authors.affiliation: Department of Chemical and Environmental Engineering, Yale University, New Haven, CT 06520, USA.
authors.forename: Allison
authors.initials: A
authors.lastname: Retotar
authors.affiliation: Department of Chemical and Environmental Engineering, Yale University, New Haven, CT 06520, USA.
authors.forename: Hamid
authors.initials: H
authors.lastname: Rismani-Yazdi
authors.affiliation: Department of Chemical and Environmental Engineering, Yale University, New Haven, CT 06520, USA. Electronic address: Jordan.Peccia@Yale.edu.
authors.forename: Jordan
authors.initials: J
authors.lastname: Peccia
mesh_terms: D061249:Batch Cell Culture Techniques / Q000295:instrumentation*; D002245:Carbon Dioxide / Q000378:metabolism*; D049109:Cell Proliferation / Q000502:physiology; D002470:Cell Survival / Q000502:physiology; D018920:Coculture Techniques / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D058086:Microalgae / Q000145:classification / Q000166:cytology / Q000502:physiology*; D058433:Photobioreactors / Q000382:microbiology*; D044444:Scenedesmus / Q000145:classification / Q000166:cytology / Q000502:physiology*
chemical_list: D002245:Carbon Dioxide
keywords: CO(2) tolerance; Microalgae ecology; Microalgal biofuels; Scenedesmus dimorphus; Wastewater