microAlgae for climate, food and feed

Microalgae are, as the name suggests, tiny unicellular organisms that dwell in the oceans and water systems around the globe. Even if they do not have features such as leaves and roots that we recognize in the more familiar, higher plants, they are capable of performing photosynthesis. In fact, they produce roughly half of the atmospheric oxygen, thereby harvesting more carbon than all the rain forests combined. They also produce a range of chemical compounds such as lipids and fatty acids, which are valuable and largely untapped resources for food and as renewable feedstock for the process industry. Microalgae species differ greatly in their capacity to bind and store carbon and in what chemicals they produce. This biodiversity has been utilized to develop, in specially designed laboratory experiments for screening and natural selection, algae that produce a maximum of the most valuable fatty acids. These fatty acids are, in turn, being transformed to versatile and even more commercially potent compounds, termed alpha olefins, using newly developed catalysts, compounds that speed up chemical reactions without themselves being consumed. The project has developed the first-ever solid catalyst selectively giving alpha olefins from fatty acids. The solid catalyst is based on an inexpensive and an easy-to-handle carbon nanomaterial that makes it possible to separate and recycle the catalyst from the otherwise liquid reaction medium. The project has involved tight collaboration between experts from disciplines ranging from biology, physics, chemistry, and information technology, to social sciences. For example, the optical properties of the microalgae, which greatly influence algae growth and production of lipids and fatty acids, have been studied by light absorption and scattering experiments. Likewise, new visualization tools have been developed, which have boosted both the development new algae strains and new catalysts. Ethical, legal, and societal aspects have been considered throughout and have influenced the choice of experiments to carry out. For example, such considerations led to the decision that algae for carbon capture and storage should not be developed as part of the project.

Different microalgae have different properties with respect to carbon harvesting and storage and it is hypothesized that the carbon-binding properties of these organisms may be improved through controlled selection and growth. Since they are already the m ost important carbon harvesters of the oceans, even a minor improvement could transform the thus designed new microalgae into a future emergency tool for limiting global warming. A screening and selection approach based on computational generation of gene tic and metabolic cell inventory combined with single cell cultures and mixed cultures will be used to develop fast-growing, high-density algae for efficient sediment formation, using laboratory-scale experiments only. The selection experiments will be ac companied by molecular- and cell-level investigations of light-use efficiency that can help optimize productivity. A similar combined selection- and light-based approach will be used to identify algae rich in lipids (oils), as well as conditions that max imize lipid production. Next, fatty acids derived from algal lipids are excellent starting points for food and renewable feedstock for chemical production, and new nanostructured catalysts for the transformation of such fatty acids into alpha-olefins will first be designed, using a novel in silico approach, and then realized and tested in experiments. The project is highly interdisciplinary and includes also development and application of powerful visualization tools to aid the algae screening and the in silico catalyst design. Similarly, ELSA-issues are actively handled and include preparatory studies with scenarios, reflections and decision-making approaches for microalgae carbon capture.