Microbial production of omega-3 fatty acids – a model based approach.

Highlights 2020

The project's contribution to the Centre for Digital Life Norway annual report 2020.

The purpose of AurOmega is to obtain a knowledge base on the biosynthesis of the omega 3 fatty acid docosahexaenoic acid (DHA) in thraustochytrids. Thraustochytrids can be cultivated at high cell concentrations and are extremely promising microorganisms for development of economic competitive production processes for omega-3 fatty acids. However, yields and productivities are still too low to compete commercially against traditional DHA raw material sources such as fish oil for low-value applications such as salmon feed, and more basic knowledge about DHA biosynthesis and lipid accumulation is needed.

During 2020, our research has advanced significantly in all of the three main scientific areas: strain construction, strain and bioprocess characterisation and modelling. The genome scale metabolic model for the organism has been refined, validated, and submitted for publication. We have had a significant breakthrough in establishing methods for genetic engineering of thraustochytrids and have made several interesting mutants that are being analysed. A manuscript describing high resolution metabolite and lipid profiles of thraustochytrids is submitted. The quantitative metabolite profiling is based on six different liquid chromatography–mass spectrometry (LC-MS)/MS methods and includes challenging metabolite groups as coenzyme As (CoAs) and nicotinamide adenine dinucleotides (NADs). Such profiling provides deep insight into the central metabolism and lipid biosynthesis pathway of thraustochytrids during growth and lipid accumulation stages. The high-resolution lipid profiling is based on supercritical fluid chromatography with MS/MS detection (published in a separate paper). The two triglyceride lipids TG 16:0_16:0_22:6 and 16:0_22:6_22:6 (16:0 palmitic acid, 22:6 – DHA) dominate in the intracellular lipid storage droplets, but we were also able to detect trace amounts of a triglyceride with DHA in all three acyl positions. Both the metabolite and lipid profiling are critical for characterisation of wild type and mutant strains, but they are also important hypothesis generators together with metabolic model simulations for further target selections.

In AurOmega, researchers with experience from the fields of synthetic biology, systems biology, bioprocess technology, analytics, and mathematical modelling are needed in order to reach our aims. We meet regularly to ensure that everyone knows the challenges the other researchers are facing and can contribute with their knowledge to aid in solving those challenges. It is only through this transdisciplinary approach that we can achieve AurOmega’s ambitious goals.

Project overview

Project lead: Per Bruheim
Institution: NTNU
Partners: SINTEF
Duration: Start-up 2017


Absolute Quantification of the Central Carbon Metabolome in Eight Commonly Applied Prokaryotic and Eukaryotic Model Systems (2020)
Lisa Marie Røst, Lilja Brekke Thorfinnsdottir, Kanhaiya Kumar, Katsuya Fuchino, Ida Eide Langørgen, Zdenka Bartosova, Kåre Andre Kristiansen, Per Bruheim

Zwitterionic HILIC tandem mass spectrometry with isotope dilution for rapid, sensitive and robust quantification of pyridine nucleotides in biological extracts (2020)
Lisa Marie Røst, Armaghan Shafaei, Katsuya Fuchino, Per Bruheim

Lipid and DHA-production in Aurantiochytrium sp. – Responses to nitrogen starvation and oxygen limitation revealed by analyses of production kinetics and global transcriptomes (2019)
Tonje Marita Bjerkan Heggeset, Helga Ertesvåg, Bin Liu, Trond Erling Ellingsen, Olav Vadstein, Inga Marie Aasen

High-throughput method for lipidomic analysis and semi-quantification of lipid classes (2019)
Zdenka Bartosova, Susana Villa Gonzalez, Per Bruheim

Supercritical fluid chromatography with mass spectrometry: A versatile tool for lipid profiling and lipid class quantitation (2019)
Zdenka Bartosova, Marit Hallvardsdotter Stafsnes, Andre Voigt, Per Bruheim

Metabolomics and fluxomics - essential approaches in optimization of bioprocesses (2019)
Marit Hallvardsdotter Stafsnes, Zdenka Bartosova, Per Bruheim

Production of omega3 fatty acids for salmon feed by heterotrophic microorganisms. (2019)
Inga Marie Aasen

Fatty acid synthesis in Aurantiochytrium sp, revealed by analyses of growth and production kinetics and global proteomes. (2019)
Inga Marie Aasen, Hanne Haslene-Hox, Helga Ertesvåg, Tonje Marita Bjerkan Heggeset, Per Bruheim

Lipid accumulation and DHA synthesis in Aurantiochytrium sp, elucidated by transcriptome, proteome and metabolome analyses. (2019)
Inga Marie Aasen, Hanne Haslene-Hox, Marit Hallvardsdotter Stafsnes, Tonje Marita Bjerkan Heggeset, Per Bruheim

Industrial microbiology – 'omics methods and modelling as tools for process optimization (2019)
Helga Ertesvåg, Hanne Haslene-Hox, Inga Marie Aasen, Eivind Almaas, Zdenka Bartosova, Tonje Marita Bjerkan Heggeset, Simone Balzer Le, E-Ming Rau, Marit Hallvardsdotter Stafsnes, Andre Voigt, Per Bruheim

All results in the CRIStin-database

Research group

The long-chain omega-3 fatty acids EPA and DHA are essential for humans, as well as for marine fish species. The current source is fish oil. As wild fish catches cannot be further increased, continued growth of marine aquaculture, in Norway and globally, is now seriously constrained by the availability of fish oil. New, sustainable sources of the EPA and DHA are needed. Thraustochytrids are unicellular eukaryotic microorganisms able to accumulate high levels of lipids. They can be cultivated at high cell concentration and are extremely promising organisms for development of economic competitive omega-3 fatty acid bioprocesses.

Despite many years of research, there is still a lack of basic understanding of fatty acid synthesis in thraustochytrids, where DHA and saturated fatty acids are produced by two competing pathways. AUROMEGA partners NTNU and SINTEF have over the last decade isolated a high number of thraustochytrid strains and characterized their lipid-producing potential.The systems biology approach in AUROMEGA will provide an enhanced understanding of what limits the DHA synthesis in thraustochytrids and how it can be improved. An iterative approach applying high integration of experimental disciplines, with extensive omics analyses, and mathematical modelling will be used. The mathematical and computational analysis will be based on genome-scale metabolic reconstruction and simulations to predict metabolic performance profiles, and complex network analysis to identify key regulatory features of DHA-synthesis, with particular focus of increasing the rate of DHA-synthesis and introduction in the triacylglycerol storage lipids. The acquired new knowledge will be translated into enhanced DHA production capabilities of selected thraustochytrid strains and laying the foundation for a sustainable and economically feasible industrial omega-3 fatty acid production process, thereby enabling further growth of one of the most important industries in Norway.