A seasonal simulation approach for culture depth influence on the temperature for different characterized microalgae strains

Abstract

Irradiance and temperature are among the most important variables that affect microalgae growth, being both difficult to control in outdoor raceway reactors utilized for large-scale production of microalgae biomass. They are mainly a function of the location of the reactors, thus, producing certain strains of microalgae in inappropriate places conduces to the failure of the systems. To be able to determine important parameters of any microalgae strains on the performance of the culture, such as the influence of irradiance and temperature, is a powerful tool in decision-making processes.In addition, whatever the strain and location, operation strategies must be defined for each specific case, such as the imposed dilution rate and culture depth, both influencing the light availability and temperature of the culture as major variables determining the biomass productivity. In this paper, a simulation-based methodology is proposed to establish the influence of season and culture depth on the 1-year age irradiance and temperature of the culture, and thus on the biomass productivity of different microalgae strains. Up to five of the most frequently produced strains, such as Spirulina platensis, Chlorella vulgaris, Nannochloropsis gaditana, Isochrysis galbana, and Scenedesmus almeriensis have been considered. The challenge is to develop an easy-to-manage decisionmaking tool for the optimal design and operation of large-scale microalgae facilities.Especially, dates for microalgae production and culture depth at which the reactors must be operated will be provided, being valid for any microalgae strain. The proposed methodology will largely contribute to the risk of investment in this field, then to enlarge the relevance of the microalgae production industry.

Recent advances and fundamentals of microalgae cultivation technology

“…[174] It was demonstrated that although several species of microalgae can tolerate high light intensity at constant temperature, heating to around 40C stops photosynthesis. [95] Further, in accordance with other studies, [52] application of mathematical modeling of photosynthesis at different temperatures and light intensities to seasonal temperature and light intensity data has demonstrated that short, 5 sm light pass increases the productivity twice in all analyzed species (C.vulgaris 2.1; N.gaditana 2.1x; S.almeriensis 2). [95] At the same time, longer light passes can be somewhat beneficial for growth in summer by controlling the temperature (C.vulgaris 1.05; N.gaditana 1.3x; S.almeriensis 1.15).…”

“…[95] Further, in accordance with other studies, [52] application of mathematical modeling of photosynthesis at different temperatures and light intensities to seasonal temperature and light intensity data has demonstrated that short, 5 sm light pass increases the productivity twice in all analyzed species (C.vulgaris 2.1; N.gaditana 2.1x; S.almeriensis 2). [95] At the same time, longer light passes can be somewhat beneficial for growth in summer by controlling the temperature (C.vulgaris 1.05; N.gaditana 1.3x; S.almeriensis 1.15). [95] Thus, it is possible to predict optimal microalgae cultivation conditions for specific microalgae strain and seasonal light and temperature variations.…”

“…[52] In the majority of bioreactors, light supply, [50][51][52]81] cell concentration, [82][83][84] CO 2 concentration, [85,86] pH, [87][88][89][90][91] temperature, [52,92] concentration of nutrients, [91] and other parameters are affected by and have an impact on the growth of microorganisms. [89,91,[93][94][95] These systems must be monitored and externally maintained to achieve optimal results [85,95] which adds to the overall cost. [49,96] Combining algae production with the utilization of the nitrogen-rich waste is one way to address this issue.…”

“…[ 95 ] At the same time, longer light passes can be somewhat beneficial for growth in summer by controlling the temperature ( C.vulgaris 1.05; N.gaditana 1.3x; S.almeriensis 1.15). [ 95 ] Thus, it is possible to predict optimal microalgae cultivation conditions for specific microalgae strain and seasonal light and temperature variations.…”

Microalgae-Based Biorefineries: Challenges and Future Trends to Produce Carbohydrate Enriched Biomass, High-Added Value Products and Bioactive Compounds

“…Rodríguez-Miranda et al [ 97 ] developed a simulation-based methodology to establish the influence of season and culture depth on the one-year irradiance and temperature of the culture, determining the biomass productivity of different microalgae strains. It is expected that such methodology could be used as an easy-to-manage decision-making tool for the optimal design and operation of large-scale microalgae facilities of the most cultivated microalgae strains ( Spirulina platensis, Chlorella vulgaris, Nannochloropsis gaditana, Isochrysis galbana , and Scenedesmus almeriensis ).…”