Further growth of the aquaculture industry requires new sources of EPA/DHA and protein, and EPA/DHA is also needed for the growing human population. Marine microorganisms are a natural source of these essential fatty acids, proteins, vitamins, minerals and other nutrients. Thus, cultivated microorganisms are possible new sustainable feed ingredients for e.g. salmon. The MIRA-project explored the potential of microalgae and bacteria as sources of marine lipids and protein, but with main focus on EPA/DHA. Both groups can be cultured based on sustainable carbon and energy sources, but the challenges for future application are different. Algae have an excellent composition of fatty acids, but a major drawback is relatively low light utilization efficiency and solutions for cost effective high-density cultivation do not exist. Lipid storing bacteria, on the other hand, do not contain DHA and EPA, but can easily be cultivated to high densities and with high lipid content.
The combined efforts of technological, physiological, genetic and biotechnological expertise of both pro- and eukaryotic organisms have secured the innovative approaches of the project. State of the art methods have been applied in the work both related to biotechnology and sustainability in a converging manner. For the lipid-accumulating bacterium Rhodococcus opacus, the necessary genes for DHA synthesis were transferred from a marine bacterium. However, DHA-production was not obtained. The reasons for this is not yet clarified.
The production of biomass and EPA/DHA by algae can be increased by increasing the efficiency in the utilization of light. One approach here was to apply selective pressure of algae that grow at high rates in an environment with variable light intensities, similar to the light experienced in photobioreactors. In addition, the new CRISPR-Cas technology was adapted to diatoms in this project, and we have established several mutant strains with reduced light harvesting complex and confirmed phenotypic differences. A selection of the most promising mutants were characterized and the project has shown that there is a great potential for strain improvement by using either directed evolution or gene editing.
For evaluation of the suitability of the microbial biomasses as feed ingredient for salmon, several large scale fermentations and cell mass processing have been performed to obtain the 12-15 kg dry weight cell mass needed for each organism in the fish feed trials. Thraustochytrid biomass, was included for comparison. All biomasses had lower digestibility than a reference diet with fish meal and oil. The thraustochytrid biomass used for comparison had the highest digestibility followed by the microalgae Nannochloropsis, whereas R. opacus displayed too low digestibility. A growth experiment using oil from R. opacus and cell mass from Nannochloropsis and the thraustochytrid showed no significant differences in growth compared to a standard feed.
Environmental, economic and social sustainability of microorganisms as feed ingredient have been evaluated. We have developed a model which estimates the carbon footprint due to feed production. The model can be used to evaluate different raw material scenarios when using microorganisms as raw materials in feed. We have also analysed the global EPA/DHA balance to identify intervention options for diminishing the global gap in EPA/DHA supply. We have arranged a workshop with different stakeholders discussing the need for omega 3 fatty acids and the social acceptance of using feed ingredients produced by GMOs.
The project partners were a multidisciplinary team, and included The Norwegian University of Science and Technology (NTNU) with Departments of Biotechnology and Food Science, Biology, and Energy and Process Engineering-Industrial Ecology, SINTEF Ocean, and SINTEF Industry. The project also had two German partners; IGW and University of Münster. The results have so far been presented in four published and three submitted scientific Papers, three master thesis, three Papers and 25 lectures at conferences and meetings have been targeting user groups and anyone interested in the topics.
Nye kjelder til dei marine feittsyrene EPA og DHA trengst for å møte eit auka behov ved den globale auken i akvakulturproduksjonen og auken til 11 milliardar menneske på jorda. Samanlikninga av potensialet ulike mikroorganismar har som kjelder til EPA/DHA i laksefôr utgjer eit kunnskapsgrunnlag om potensialet til kvar gruppe. Vidare såg vi i prosjektet på kva delar i heile verdikjeda som det var viktigast å forbetre for å optimalisere dei mikrobielle produksjonsprosessane. Etablering av eit globalt EPA/DHA-budsjett ga innsikt i kva straumar som dominerer og kvar tapa i budsjettet skjer. Dette er eit viktig kunnskapsgrunnlag for å kunne informere og ta avgjerder både når det gjeld konsumentar, produsentar, forskarar og politikarar.
For all vidare forsking på mikroalgar var etableringa av CRISPR-Cas9 metoden i kiselalgar ein viktig milepæl. Analyser av dei første mutantane kunne allereie vise skilnadar mellom fotosystema i landplanter og kiselalgar.
Marine microorganisms are a natural source of essential fatty acids, proteins, vitamins, minerals and other nutrients. Thus cultivated microorganisms are a sustainable resource for salmon feed ingredients on both short and long term.
The project will exp lore the potential of microalgae and bacteria as sources of marine lipids and protein. Both groups can be cultured based on sustainable carbon and energy sources (light/CO2 and organic waste) and have high protein contents, but the challenges are differen t. Algae have excellent composition of fatty acids, but solutions for high density cultivation do not exist, whereas lipid storing bacteria do not contain DHA and EPA, but can easily be cultivated to high densities. The metabolic pathway for EPA/DHA-synth esis will be introduced in the lipid-accumulating bacterium Rhodococcus opacus, whereas the biomass and EPA/DHA-productivities of photosynthetic microalgae will be improved by increasing the efficiency of light utilization. The microbial biomass will be e valuated in digestibility and growth tests with salmon. Evaluation of environmental, economic and social sustainability is also included.
The combined efforts of technological, physiological, genetic and biotechnological expertise of both pro- and eukary otic organisms secure the innovative approaches of the project. State of the art biotechnological methods will be applied, including synthetic biology, genome editing and directed evolution. The project will establish biotechnological tools and competence that are no-existent nationally at present. State of the art methods will be used to evaluate sustainability.
A full evaluation of achievements and progress will be made after 24 months
The project partners are a multidisciplinary team and include The No rwegian University of Science and Technology (NTNU) with Departments of Biotechnology, Biology, and Energy and Process Engineering-Industrial Ecology, SINTEF Fisheries and Aquaculture, SINTEF Materials and Chemistry