Control of the pH for marine microalgae polycultures: A key point for CO2 fixation improvement in intensive cultures

Type Article
Date 2020-05
Language English
Author(s) Gales Amandine1, 2, Triplet Sebastien3, Geoffroy Thibault3, Roques Cécile1, Carre Claire1, Le Floc'h Emilie4, Lanfranchi Mélissa1, 3, Simier Monique5, Roque D'Orbcastel Emmanuelle1, Przybyla CyrilleORCID1, Fouilland Eric4
Affiliation(s) 1 : MARBEC, Univ Montpellier, IRD, CNRS, IFREMER, Montpellier, Sète & Palavas, France
2 : LBE, Univ Montpellier, INRA, Narbonne, France
3 : IFREMER L-SEA, Palavas, France
4 : MARBEC, Univ Montpellier, IRD, CNRS, IFREMER, Montpellier, Sète & Palavas, France
5 : MARBEC, Univ Montpellier, IRD, CNRS, IFREMER, Montpellier, Sète & Palavas, France
Source Journal Of Co2 Utilization (2212-9820) (Elsevier), 2020-05 , Vol. 38 , P. 187-193
DOI 10.1016/j.jcou.2020.01.019
WOS© Times Cited 4
Keyword(s) Carbon yield, Microalgal diversity, pH, Predators
Abstract

Recently, CO2 recycling for the production of valuable microalgae has acquired substantial interest. Most studies investigating CO2 conversion efficiency in algal cultures were based on single species, although a stabilising effect of algal diversity on biomass production was recently highlighted. However, addition of CO2 into polyalgal cultures requires a careful control of pH; performance of CO2 conversion, growth and carbon biomass production are affected by pH differently, depending on the species of microalgae. This study investigates the efficiency of CO2 conversion by natural marine algal assemblage cultivated in open, land-based raceways (4.5 m3, 10 m2), working as high rate algal ponds (HRAP). Ponds were enriched with nitrogen and phosphate, pure CO2 was added and algal cultures were grown under three different fixed pH levels: pH 6, 7 and 8. The highest conversion of photosynthetically fixed CO2 into carbon biomass (40 %) was reached at pH 7, an intermediate level, due to the partial CO2 asphyxiation of algal predators (copepods, ciliates), while being under the suboptimal conditions for the development of marine amoebae. Under this pH, the theoretical maximal biological conversion of available CO2 into carbon biomass was estimated to be 60 % in naturally inoculated open ponds.

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Gales Amandine, Triplet Sebastien, Geoffroy Thibault, Roques Cécile, Carre Claire, Le Floc'h Emilie, Lanfranchi Mélissa, Simier Monique, Roque D'Orbcastel Emmanuelle, Przybyla Cyrille, Fouilland Eric (2020). Control of the pH for marine microalgae polycultures: A key point for CO2 fixation improvement in intensive cultures. Journal Of Co2 Utilization, 38, 187-193. Publisher's official version : https://doi.org/10.1016/j.jcou.2020.01.019 , Open Access version : https://archimer.ifremer.fr/doc/00612/72403/