Growth, Proximate Composition, and Photosynthesis of Chlorella vulgaris Cultures Between a Photobioreactor Based in a Compound Parabolic Concentrator and a Plain Tubular System for a Biorefinery

• Published in: Bioenergy research 2022-03, Vol.15 (1), p.230-241
• Main Authors: Stephens-Camacho, Beatriz Eugenia, Sauceda-Carvajal, Daniel, del Pilar, Sánchez-Saavedra M
• Format: Article
• Language: English
• Subjects: Algae; Aquatic microorganisms; Biochemical composition; Biomass; Biomedical and Life Sciences; Biorefineries; Carbohydrates; Cell culture; Cell size; Chlorella; Chlorella vulgaris; Composition; Concentrators; Fine chemicals; Growth; Growth rate; Irradiance; Life Sciences; Light intensity; Lipids; Luminous intensity; Microalgae; Photosynthesis; Pigments; Plant Breeding/Biotechnology; Plant Ecology; Plant Genetics and Genomics; Plant Sciences; Productivity; Wood Science & Technology
• ISSN: 1939-1234; 1939-1242
• DOI: 10.1007/s12155-021-10304-1

This study compared the growth, proximate composition, and photosynthesis of Chlorella vulgaris cultures between a compound parabolic concentrator (CPC) coupled to a glass tube and a plain tube without the concentrator. The system with a concentrator increased the irradiance level on the culture by 351% and the average light intensity on cells by 462% compared to the plain tube system. During the exponential growth phase, the growth rate of C. vulgaris was higher in the tube system (1.14 div by day −1 ) versus the system with a concentrator (0.98 div by day −1 ), but the cell size was higher in the system with the concentrator (11.23 μm) compared with the tube system (6.28 μm). From day 2 to 4 of culture, biomass production (as organic dry weight: 3.43 to 9.85 pg cell −1 ) and proximate composition (proteins: 12.13 to 31.36 pg cell −1 , lipids: 10.44 to 17.55 pg cell −1 , and carbohydrates: 13.04 to 38.38 pg cell −1 ) were higher in the system with concentrator versus tube system. The biomass productivity (0.07 to 0.37 g L −1 ) and lipid productivity (1.23 to 5.94 g L −1  day −1 ) were significantly higher in the tube system in the same period. From a practical perspective, these results emphasize the importance of controlling irradiance in C. vulgaris cultures and suggest that a CPC can be used for microalgae cultures to increase the irradiance and induce stress by light. The CPC system can be used to shift the biochemical composition of microalgae cells toward the production of fine chemicals (e.g., pigments and lipids).