Abstract
This work dealt with the study of growth parameters, pigments production, and bioenergetic aspects of the microalga Dunaliella tertiolecta in different culture media. For this purpose, cultures were carried out in Erlenmeyer flasks containing F/2 medium, Bold’s Basal medium, or an alternative medium made up of the same constituents of the Bold’s Basal medium dissolved in natural seawater instead of distilled water. D. tertiolecta reached the highest dry cell concentration (Xmax = 1223 mgDM·L−1), specific growth rate (µmax = 0.535 d−1), cell productivity (PX = 102 mgDM·L−1·d−1), and photosynthetic efficiency (PE = 14.54%) in the alternative medium, while the highest contents of carotenoids (52.0 mg·g−1) and chlorophyll (108.0 mg·g−1) in the biomass were obtained in Bold’s Basal medium. As for the bioenergetic parameters, the biomass yield on Gibbs energy dissipation was higher and comparable in both seawater-based media. However, the F/2 medium led to the highest values of moles of photons absorbed to produce 1 C-mol of biomass (nPh), total Gibbs energy absorbed by the photosynthesis (ΔGa) and released heat (Q), as well as the lowest cell concentration, thus proving to be the least suitable medium for D. tertiolecta growth. On the other hand, the highest values of molar development of O2 and consumption of H+ and H2O were obtained in the alternative medium, which also ensured the best kinetic parameters, thereby allowing for the best energy exploitation for cell growth. These results demonstrate that composition of culture medium for microalgae cultivation has different effects on pigments production, growth kinetics, and bioenergetics parameters, which should be taken into consideration for any use of biomass, including as raw material for biofuels production.
Highlights
Species belonging to the Dunaliella genus are unicellular and biflagellate green microalgae that grow under high salinity and irradiance conditions [1]
The F/2 medium contained mineral salts, trace elements, and vitamins dissolved in natural seawater previously filtered through membranes with 0.22 μm pore diameter [26]; the Bold’s Basal medium is a well-known broth made up of mineral salts dissolved in distilled water [27]; while the alternative medium was composed of the same mineral salts as the Bold’s Basal one but using seawater (Table 1) instead of distilled water
In F/2 medium, the exponential growth phase started after about 1 day of cultivation, and cell density achieved a value of 452 mgDM ·L−1 on the fifth day, after which the microalga entered the stationary growth phase that continued until the end of cultivation
Summary
Species belonging to the Dunaliella genus are unicellular and biflagellate green microalgae that grow under high salinity and irradiance conditions [1]. Cultivation has been widely applied because its biomass is a source of valuable compounds such as polysaccharides, lipids, vitamins, proteins, and pigments, mainly carotenoids and chlorophyll, that can be used in several biotechnological applications [2,3,4,5]. Microalgae can be cultivated under different conditions, and several factors such as light intensity, photobioreactor type and configuration, mixing regime, temperature, and culture medium composition may influence cell growth and biomass composition [7]. The composition of culture medium is one of the most important issues to be tackled in commercial production of microalgal biomass
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
