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Publication
A novel bench-scale photobioreactor for continuous cultivation of microalgae [Poster]
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| 1.87 MB | Adobe PDF |
Advisor(s)
Abstract(s)
ABSTRACT: There are different types of carbon intensive industries. While some operate with daily intervals, others must be maintained in continuous operation, sometimes for weeks or months. Processes that depend on microbiological activity are usually of the second category, resulting in the continuous production of CO2 during extensive periods of time. In order to help mitigate climate change, alternative methods of carbon capture into added-value products have been the focus of research. Autotrophic microalgae cultures can be employed to sequester the carbon present in these streams, generating new products, while increasing process sustainability. However, to sequester these emissions microalgal bioreactors must also function under continuous constant conditions, requiring photobioreactors (PBRs) that can act as chemostats for long periods of time. Moreover, there is currently a lack of studies and design alternatives using microalgal chemostats. Most works tend to focus on batch assays or semi-continuous processes, presenting different responses depending on the growth stage of the culture, or the time of day. The present work is centred on the development of a novel continuous bench-scale PBR. This system uses an innovative recirculation concept to combine three different units (retention vessel, photocollector and degasser) that operate as a single autotrophic chemostat, allowing the study of carbon sequestration from a biogenic CO2-rich constant air stream. The novel PBR was tested by cultivating the microalga Haematococcus pluvialis at different dilution rates (0.1-0.5 d-1), while using as sole carbon source an air stream containing ≈0.35 vol% of CO2 (produced by a coupled heterotrophic bacterial chemostat). The results obtained revealed that the system could operate as a chemostat, allowing the production of stable cultures with proportional responses to the changes in dilution rates for more than 3 months, reaching a maximum biomass productivity of 183 mg/L/d, with a carbon fixation efficiency of ≈39% at 0.3 d-1. This makes the PBR prototype a promising tool to study/optimise integrated heterotrophic and autotrophic continuous processes, or constant sequestration of stable CO2-rich streams, making it easier to gather data for future scale-up.
Description
Keywords
Microalgae Haematococcus pluvialis Continuous culture Biogenic CO2 CO2 sequestration Chemostat
Citation
Silva, Tiago... et.al - A novel bench-scale photobioreactor for continuous cultivation of microalgae. In: Abstract Book of 19th International Conference on Renewable Resources & Biorefineries (RRB’2023), 31 May – 2 June, Riga, Latvia, p. 105-106. (Poster 79)