Sustainable production of arachidonic acid (AA) by a novel thraustochytrid strain

Author: Vidana Arachchige Kashmini Nimesha Appuhami

  • Thesis download: available for open access on 18 Nov 2024.

Appuhami, Vidana Arachchige Kashmini Nimesha, 2021 Sustainable production of arachidonic acid (AA) by a novel thraustochytrid strain, Flinders University, College of Medicine and Public Health

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For a healthy life, it is vital to obtain a higher proportion of polyunsaturated fatty acids (PUFAs) as daily supplements. Various clinical studies have advocated the role of PUFAs, especially arachidonic acid (AA, 20:4n-6) and docosahexaenoic acid (DHA, 22:6n-3) in supporting nutrition in infants. However, only limited sources such as fish oil are known for ensuring PUFAs availability in the human diet. Therefore, more sustainable resources are needed to produce PUFAs. AA is found in high proportion in eggs, meat and poultry, and marine fish oil but it cannot be produced by mammalian cells. Therefore, it should be obtained externally through food supplements, which are meeting the increasing demand of the vegetarian population. The microbial source can be an alternative for producing fatty acid, as these are non-polluting, regarded sustainable sources to produce PUFAs, and acceptable by the vegetarians. Thraustochytrids have been applied as a commercial resource for producing PUFAs. These marine microbes have an attractive PUFA profile that comprises of omega-3 and omega-6 fatty acids. The current study investigated the heterotrophic production of omega-6 fatty acids. The objective of this study was to produce AA through thraustochytrid and increase its yield through fermentation approach which is environment friendly. The present study examined the effects of various medium components (carbon, salt, and yeast concentration) and fermentation parameters (pH, temperature, agitation rate) on the production of AA from an in-house thraustochytrid S2 strain. Different chemical modulators (BA, IBA, KT, and IAA) were added to the fermentation media to enhance AA production. Addition of 6-benzyl adenine (BA) at 15 mg/ L resulted in the highest AA accumulation. Under the optimal conditions of pH 6.5, temperature 22 0C, agitation 150 rpm, salt and yeast concentration (20 g/L), the maximum biomass (22.1 g/L), and AA (3%) production were observed. In addition to AA production, other prominent fatty acids such as palmitic acid (C16:0), docosahexaenoic acid (C22:6), and palmitoleic acid (C16:1n7) were also identified as part of total fatty acids. Feeding of a precursor rich in unsaturated fatty acids further enhanced AA, DCW, and lipid yields using thraustochytrid S2 strain, thus, achieving the objectives of the study.

Keywords: Arachidonic Acid (AA), PUFA,omega-6 fatty acids,DCW, TFA, Thraustochytrids,Heterotrophic fermentation, Fatty Acid Methyl Esters (FAMEs) and Gas chromatography analysis

Subject: Biotechnology thesis

Thesis type: Masters
Completed: 2021
School: College of Medicine and Public Health
Supervisor: Associate Professor Munish Puri