Research
Astaxa is active in applied research and development in microalgal biotechnology. A main emphasis is laid on valuable components from microalgae that can be utilized in cosmetics and in aquaculture. We are conducting research projects in cooperation with Universities and private research institutes as well as industrial research with commercial partners. Our main fields of interest are:
Omega-3 fatty acids from microalgae
The demand for polyunsaturated fatty acids (PUFA) as additives in animal and human diet is strongly increasing. Animals are not able to synthesize ω-3 fatty acids de novo, and recent research results indicate a strong correlation between intake of those PUFA and beneficial health effects such as the prevention of cardiovascular diseases and Alzheimer’s disease, the abatement of depression and the inhibition of cancer.
At present ω-3 fatty acids are being produced from oily fish, but concerns regarding the accumulation of pollutants, especially toxins like PCB etc., as well as the continued exploitation of fish stocks in order to meet the demands for an expanding market are drawing the attention to other resources. Since ω-3 PUFA in fish oils is actually derived via the marine food chain from zooplankton consuming ω-3 PUFA-synthesizing microalgae, the production of microalgae in closed photobioreactors with high quality and controlled composition appears reasonable.
But so far, only relatively few wild-type microalgae are known to produce ω-3 PUFA such as EPA (eicosapentaenoic acid, C20:5, n3) and DHA (docosahexaenoic acid, C22:6, n3) in high concentrations, e.g. Schizochytrium (DHA), Crypthecodinium (DHA) and Phaeodacty-lum (EPA). Therefore we conducted a screening for suitable microalgae, including marine diatoms with the aim of photoautotrophic biomass production.
Lipids were extracted and the fatty acid profile was determined by GC after conversion to fatty acid methyl esters. As major fatty acids, depending on the individual strain, C16:0, C16:1 or C18:1 have been identified. EPA contents varied between 17,1 and 45,4% of total fatty acids, whereas the total fat content was about 30% of dry matter.
A main emphasis of the research lies on the suitability of these phototrophic microorganisms for the production of single cell oils with a high PUFA content by the application of large scale photobioreactor technology (85.000 litre volume IGV-modules).
To use the phototrophic microorganisms as source for EPA rich oils as demanded for example for fish feed, especially the oil content and the fatty acid profile were controlled during cultivation under various laboratory conditions to find out optimum for growth, oil production, and the formation of EPA. In influence of temperature, light intensity and nutrient supply on the PUFA composition and content was investigated.
Following the selection of the best-suited microalgal strains with regard to PUFA production under laboratory conditions, up-scaling experiments were carried out and different candidates with good potential for EPA-production in industrial scale were identified. The produced ω-3 rich oil will be suitable for use in the food and feed industry as an alternative for fish oil.
Carotenoids from microalgae
The ability to synthesize secondary carotenoids such as astaxanthin and canthaxanthin under nitrogen depreviation and high light conditions in different algal cultures has been reported from various authors over 100 years ago (Wollenweber 1907). Until now, only a few microalgae are being investigated for their carotenoid production potential and only two of them are biotechnologically produced: Duanliella for ω-carotene production and Haematococcus pluvialis for astaxanthin production. However, the interest in carotenoids from microalgae is due to the high turnover of the global carotenoid market (more than 1 bn. US$ in 2009) ever growing.
We are focussed on the investigation of different green, fast dividing microalgae and cultivation techniques targeted at elevated primary and secondary carotenoid yields. The total carotenoid content can thereby be enhanced by the use of media additives and specific process management. The results of our research are directly up-scaled to our industrial scale photobireactors and can therefore deliver useful insights in carotenoid formation in various green microalgae for the production of microalgal carotenoids in industrial scale.
Wollenweber, W. (1907). "Untersuchungen über die Algengattung Haematococcus." Ber Deutsch bot Ges 26: 238-298.
Carbon dioxide sequestration using microalgae
The research aims the capture and storage of carbon dioxide being produced by the combustion process by microalgae. This process offers the possibility of reducing the emission of anthropogenic greenhouse gases as well as saving money on carbon dioxide emission certificates. Microalgae, the major natural CO2-fixing organisms on the planet, can be a successful solution for that issue.
They are able to transform CO2 from flue gases directly into organic material such as valuable proteins, lipids and carbohydrates by the photosynthetic process that is driven by sunlight. This process requires land, water, sunlight as well as nitrates and phosphates as nutrients. The application of vertical tubular photobioreactors in industrial scale, can achieve high cell densities that are directly linked to CO2 fixation rates. At the same time the vertical orientation will reduce the necessary land space that is needed for microalgal culturing.
