Cost-effective production of Omega-3 fatty acids and proteins from Schizochytrium sp. biomass for feed application

Author: Kanchan Ghimire Shrestha

  • Thesis download: available for open access on 10 Jan 2027.

Ghimire Shrestha, Kanchan, 2023 Cost-effective production of Omega-3 fatty acids and proteins from Schizochytrium sp. biomass for feed application , Flinders University, College of Medicine and Public Health

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Fish meal and fish oil are the major sources of omega-3 fatty acids. The production of fish meal and fish oil relies on captured fisheries but due to factors, such as climate change, overfishing, and sustainability goals, the worldwide supply of wild-caught fish has declined. Microalgae with high lipid content and rapid growth rate can serve as a good alternative to fish meal and fish oil. However, high cost of production is one of the hindrances in microalgae cultivation. Thus, the main aim of this study was to utilise inexpensive carbon sources, such as glycerol to obtain high omega-3 fatty acids as well as protein in Schizochytrium sp. DT3 strain, which possess potential application as aquaculture feed. Glycerol, sodium acetate, sodium bicarbonate as well as glucose were utilised as either sole carbon source or mixed carbon sources for Schizochytrium sp. DT3 cultivation. The maximum biomass obtained was 18.65 g/L using glycerol (40 g/L) in plain Erlenmeyer flask at 25°C at 120 h of incubation. In addition, maximum lipid content was obtained (48%) when glycerol (80 g/L) was used as a sole carbon source in baffled Erlenmeyer flask at 25°C at 96 h. Further, maximum omega-3 fatty acid (34.35 % of TFA) was achieved using sodium bicarbonate and glucose as a mixed carbon source. The maximum protein (55.53%) was obtained at 24 h. When compared with two commercial fish feeds, the lipid and omega-3 fatty acid content of Schizochytrium sp. DT3 biomass was significantly higher. This study demonstrates that utilising low-cost carbon sources, such as glycerol, sodium acetate and sodium bicarbonate can effectively facilitate biomass production with elevated levels of lipids, protein and omega-3 fatty acids thereby benefitting aquaculture.

Keywords: Omega-3 fatty acid, microalgae, Schizochytrium sp., Thraustochytrid, microalgal protein, aquaculture feed, low-cost substrate, glycerol

Subject: Biotechnology thesis

Thesis type: Masters
Completed: 2023
School: College of Medicine and Public Health
Supervisor: Munish Puri