Agnieszka Janina Zygadlo Nielsen – Københavns Universitet

17. december: Mikroalger omdanner sollys til kostbar medicin

KU's Alumneforening har bedt forskere fra Københavns Universitet om at fortælle om deres aktuelle forskningsprojekter. Det er tilsammen blevet til de 24 låger i årets forskningsjulekalender, hvor du kan læse om alt fra juleflæsk til mediernes fremstilling af julen. I dagens låge fortæller Agnieszka Janina Zygadlo Nielsen fra Det Naturvidenskabelige Fakultet om sin forskning i mikroalger og fotosyntese.

Microalgae as biofactories to produce active compounds

Plants and algae are responsible for life on earth thanks to photosynthesis. Photosynthesis consists on converting sunlight energy, CO2 and water into oxygen and chemical energy. Some plants have also medicinal values since they produce an active compound that can be used in medicinal applications. For example, morphine coming from the seedpod of poppy plants or taxol -an anti-cancer drug extracted from the bark of yew trees.

Extraction of the medicinal compound from its native plant is often costly and low efficiency. The compounds are also nearly impossible to synthetize chemically or derive from fossile fuel in large amounts. A large effort is focused on identifying the metabolic pathways responsible for biosynthesis of these active compounds. Over 300 000 plants have been described and there are probably as many to identify. 200 000 plant molecules have been identified but they have been not all tested for applications yet, creating a potential of chemicals for human use to be discovered. Enzymes are active proteins involved in metabolic processes that produce a chemical of interest.

Photosynthetic microalgae growing in a photobioreactor in a laboratory scale

In biotechnology, organisms like the bacteria and the yeast are commonly used today to produce lots of biocompounds such as food additives, pharmaceuticals, fuel, other commodity chemicals. These organisms require carbon rich and sugar rich media to grow. A constant supply constant and substantial amounts are needed. However, some active proteins, enzymes, coming from plants are hard to express in these conventional production hosts.

One of the oldest living organisms on earth

Microalgae are one of the oldest living organisms on earth, some of them are evolutionary ancestors of the landplants. Recent development of molecular tools enables metabolic engineering of microalgae to produce chemicals. They only require sunlight, atmospheric CO2 and water with minimal nutrients but no other carbon source. It is a promising platform to produce commodity chemicals in a sustainable manner.  

In our research group lead by Prof. Poul Erik Jensen, we connect photosynthesis to metabolic pathways to produce medicinal compounds using light and water as main energy source. For that, we express the active enzymes directly next to the protein complexes responsible for photosynthesis. Light driven biosynthesis of medicinal compounds is now possible in microalgae.

Engineering of microalgae for light driven biosynthesis. Active enzymes from medicinal plants are expressed in the chloroplast where photosynthesis takes place. The photosynthetic apparatus converts light energy to chemical energy that can be directly used by active enzymes to produce medicinal compounds.

Metabolic engineering of microalgae is expanding rapidly and focused on increasing the production yields so it can become an alternative production platform to conventional production hosts.

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I morgen kan du i KU's forskningsjulekalender 2016 møde Karina Kim Egholm Elgaard, der fortæller, hvordan forskning nogen gange kan føles som en eventyrlig rejse.