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Optimization of microalgae cultivation messastrum gracile using different light intensities in photo-autotrophic and mixotrophic regime

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Débora Cristina Fenerick
Total Authors: 1
Document type: Master's Dissertation
Press: Jaboticabal. 2021-09-09.
Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal
Defense date:
Advisor: Lúcia Helena Sipaúba Tavares

The microalgae cultivation is an area of knowledge highlighted among academic research currently and in business, since those microorganisms synthesize a variety of substances of human interest in many sectors, such as proteins, lipids and pigments. The cost reduction for algae cultivation with commercial culture media and electricity is necessary, as they represent the majority of production costs. The approach employed in the present research considered the growth, biological and biochemical development of Messastrum gracile and economic aspects of the cultivation. Thus, the objective of this research was to test two culture mediums, a commercial medium (CHU12) and other based on macrophyte extract Eichhornia crassipes (ME – Macrophyte Extract), under different light intensities (30, 60, 90 and 120 μmol photons m-2 s -1 ), arranged in two cultivation conditions, photoautotrophic and mixotrophic with employment of sugar cane molasses as carbon source, all experiments under different culture conditions and culture media were carried out in a 2-liter flask, in triplicate for a period of 21 days The macrophyte extract medium under 120 μmol photons m-2 s -1 photoautotrophic conditions and presented the highest mean cell density of 165 x 105 cells mL-1 and the specific growth rate. Protein content was higher at day 7 of cultivation in mixotrophic conditions, under 90 and 120 μmol photons m-2 s -1 in ME medium (1.9 mg mL-1 ). The lipid content was higher under light intensity of 60 μmol photons m-2 s -1 in commercial medium CHU12, in both cultivation conditions. Except for lipid, the cultivation in macrophyte extract medium was more effective in M. gracile development with higher biomass and protein than CHU12 medium. The ME culture medium provided a better economic viability with the highest operating profit in the mixotrophic culture condition, at an intensity of 90 μmol photons m-2 s -1 (US$ 9,043), being 133% cheaper than the CHU12 medium in intensities of 60, 90 and 120 μmol photons m-2 s -1 . The crops evaluated in this study are related to production processes and allow the production of different products (proteins, bioenergy and pigments). Thus, the commercial field of the enterprise only increases by changing the industrial process to obtain the desired product, without the need to change the production infrastructure. Therefore, using biological residues from aquaculture (macrophytes) and agroindustry by-products (molasses) reduce production costs and provide a destination for some residues that can cause harmful impacts to the environment (AU)

FAPESP's process: 19/21053-1 - Optimization of Messastrum gracile cultivation in different light intensities in photo-autotrophic and mixotrophic schemes
Grantee:Débora Cristina Fenerick
Support Opportunities: Scholarships in Brazil - Master