Antares I: a Modular Photobioreactor Suitable for Photosynthesis and Bioenergetics Research

Abstract

Oxygenic photosynthesis is responsible for most of the fixation of atmospheric CO2. The microalgal community can transport atmospheric carbon into biological cycles in which no additional CO2 is created. This represents a resource to confront the actual climate change crisis. These organisms have evolved to adapt to several environments and different spectral distribution of light that may strongly influence their metabolism. Therefore, there is a need for development of photobioreactors specialized in addressing spectral optimization. Here, a multi-scale modular photobioreactor made from standard glass materials, ad hoc light circuits, and easily accessible, small commercial devices is described. The system is suitable to manage the principal culture variables of research in bioenergetics and photosynthesis. Its performance was tested by growing four evolutionary-distant microalgal species with different endosymbiotic scenarios: Chlamydomonasreinhardtii (Archaeplastida, green primary plastid), Polytomella parva (Archaeplastida, colorless plastid), Euglena gracilis (Discoba, green secondary plastid), and Phaeodactylum tricornutum (Stramenophiles, red secondary plastid). Our results show an improvement of biomass production, as compared to the traditional flask system. The modulation of the incident light spectra allowed us to observe a far-red adaptation in Euglenagracilis with a difference on paramylon production, and it also significantly increased the maximal cell density of the diatom species under green light. Together, these confirm that for photobioreactors with artificial light, manipulation of the light spectrum is a critical parameter for controlling the optimal performance, depending on the downstream goals.

The Microalgae <em>Chlamydomonas </em>for Bioremediation and Bioproduct Production

“…A multi-scale PBR, Antares I, with incident light modulations ranging from 10 to 300 µmol photons m −2 s −1 , has been tested with C. reinhardtii and has shown improvement in biomass production compared to traditional PBRs. With Antares I the estimated doubling time for Chlamydomonas culture is half of that reported for culture using similar media and light conditions [36]. These findings demonstrate the diverse applications and research efforts related to the optimization of PBR for Chlamydomonas cultivation.…”

Significance and Applications of the Microalgae Chlamydomonas and its Bacterial Consortia

“…The multi-scale modular PBR, Antares I, has been tested with C. reinhardtii and has shown improved biomass production compared to traditional flask systems. With Antares I, the estimated doubling time for Chlamydomonas culture was almost half of that reported for culture using similar media and light conditions [44]. A drawback of monoculture microalgae in PBRs is that dissolved oxygen accumulation can reach up to 400% of air saturation, which is detrimental to microalgae growth [45].…”