A comparison between microalgal autotrophic growth and metabolite accumulation with heterotrophic, mixotrophic and photoheterotrophic cultivation modes. (May 2022)

• Record Type: Journal Article
• Authors: Abreu, Ana P.; Morais, Rui C.; Teixeira, José A.; Nunes, João
• Is Part Of: Renewable & sustainable energy reviews. Volume 159(2022)
• Publication Date: 2022-05
• Subjects: Microalgae -- Autotrophic -- Mixotrophic -- Heterotrophic -- Photoheterotrophic -- Organic carbon -- Bioeconomy; Aut. autotrophic -- CAGR Compound Annual Growth Rate -- CEF cyclic electron flow -- Chl chlorophyll -- DW dry weight -- EMP Embden-Meyerhof pathway -- G3P glyceraldehyde-3-phosphate -- Het. heterotrophic -- Mix. mixotrophic -- mPt 1 kPt equals to the annual impact of one European citizen -- NPQ non-photochemical quenching -- OCS organic carbon substrate -- OP open pond -- PE photosynthetic efficiency -- PHet. photoheterotrophic -- Pmax maximum productivity -- PPC phosphoenolpyruvate carboxylase -- PPP pentose phosphate pathway -- PSI photosystem I -- PSII photosystem II -- PUFA polyunsaturated fatty acids -- qP photochemical quenching -- TCA tricarboxylic acid -- TSCS two-stage cultivation strategy -- μaut autotrophic growth rate -- μmix mixotrophic growth rate; Renewable energy sources -- Periodicals; Power resources -- Periodicals; Énergies renouvelables -- Périodiques; Ressources énergétiques -- Périodiques; 333.794
• DOI: 10.1016/j.rser.2022.112247
• Languages: English
• ISSNs: 1364-0321

Abstract

Abstract: Microalgae are sustainable feedstock for healthy food and feed, organic drugs, ecological polymers, green chemicals and dyes, biofuels, biofertilizers, and environmental bioremediation technologies. Despite its enormous promises, microalgae cultivation is expensive and thus large-scale production is centred on low volume/high value markets, such as the specialty food and feed, dietary supplements and pharmaceuticals. Large-scale microalgal cultivation is severely limited by the low biomass productivity achieved in current production systems, due to low photosynthetic efficiency. Furthermore, the management of carbon dioxide (CO2 ) for microalgal large-scale production is costly and faces technological constraints. The cultivation of microalgae in media supplemented with organic carbon substrates, with or without light, can significantly increase biomass productivities and overcome the technical constraints associated to CO2 supply. This review collects quantitative data to compare microalgal autotrophic growth and metabolite accumulation with heterotrophic, mixotrophic and photoheterotrophic cultivation modes. Critique hypotheses are proposed to explain the increase in biomass productivity once microalgae are supplied with organic carbon molecules. The main cultivation parameters that could affect biomass accumulation are also analysed. Supplementation of microalgae with organic carbon substrates could be a suitable strategy towards a microalgal economy, despite the constraints and challenges that have to be overcome and that are also analysed. Highlights: Large-scale microalgal cultivation is constrained by low biomass productivities. Photosynthetic efficiency is low in autotrophic production systems. Large-scale management of carbon dioxide faces economic and technical constraints. Microalgal biomass productivities can be increased with organic carbon substrates. Selection of growth model is critical for successful microalgae production system.