Enhancing microalgae flocculation with sodium alginate for efficient harvesting in culture medium
List of Authors
  • Azianabiha A Halip Khalid, Nurammaroh Aisyhah Ghazali

Keyword
  • Immobilised Microalgae, Microalgae Cultivation, Sodium Alginate, Chlorella Vulgaris, Harvesting Microalgae

Abstract
  • Microalgae are rich in esters, glycerol, proteins, polysaccharides, lipids, vitamins, and unsaturated fatty acids, making them ideal for producing bioethanol, biofuels, and other nutritious and bioactive substances. They also have a notable capacity for carbon sequestration, converting carbon dioxide into organic matter. Efficient harvesting is essential to maximize the yield of these valuable compounds. Traditional methods, such as centrifugation, have limitations, including high energy consumption, significant costs, and potential for cell damage or environmental pollution. Sodium alginate, known for its high adsorption capability and heavy metal removal properties, offers a promising alternative for microalgae harvesting. This study explores the effectiveness of sodium alginate in microalgae harvesting and compares the growth rates of microalgae in suspended cultures versus immobilized systems. Results showed that while suspended cultures exhibited slightly better performance with a shorter lag phase and faster growth due to unrestricted access to nutrients and light, the immobilized group demonstrated significantly higher biomass producticity. Specifically, the immobilized microalgae produced 309.17 g/L/day, compared to 32.50 g/L/day in the control culture, underscoring the efficiency of flocculation with sodium alginate. Furthermore, characterization of the microalgae beads using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy-Energy Dispersive X-Ray Analysis (SEM-EDX) confirmed their stability and purity. These findings contribute to more sustainable microalgae harvesting practices, enhancing both profitability and environmental sustainability.

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