Aðalbygging
The Aula
Doctoral candidate: Antoine Didier Christophe Moenaert
Title of thesis: Cell factory and cell-free conversions of brown seaweed to valuable compounds by metabolic engineering
Opponents:
Dr. Oddur Þór Vilhelmsson, Professor at the Faculty of Natural Resource Sciences, University of Akureyri
Dr. Magnus Carlquist, Professor at the Faculty of Engineering, Lund University, Sweden
Advisor: Dr. Snædís Huld Björnsdóttir, Professor at the Faculty of Life and Environmental Sciences, University of Iceland
Other members of the doctoral committee:
Dr. Guðmundur Óli Hreggviðsson , Professor at the Faculty of Life and Environmental Sciences, University of Iceland
Dr. Ólafur Héðinn Friðjónsson, Research leader at Matís, Iceland
Dr. Eva Nordberg Karlsson, Professor at the Faculty of Engineering, Lund University, Sweden
Chair of Ceremony: Dr. Snæbjörn Pálsson, Professor and Head of the Faculty of Life and Environmental Sciences, University of Iceland
Abstract
In the context of fossil fuel shortage and the need for more sustainability, recent emphasis has been put on finding new biomasses suitable for biotechnological applications, such as brown seaweed. They are the most abundant seaweed in Northern Europe and contain laminarin and alginate as main carbohydrates. The aim of this study was to utilize this biomass as a feedstock for microorganisms, using metabolic engineering, both in vivo and in vitro, to improve conversion of these carbohydrates to value-added products. The anaerobic thermophilic bacteria Thermoanaerobacterium AK17 was used as a cell factory and engineered to produce ethanol as the sole fermentation product. The resulting strain AM6 reached an ethanol yield close to the maximum theoretical yield (95%), using mannitol, glucose and oligosaccharides from seaweed hydrolysate. Further genetic manipulations could increase the productivity of this new strain, by enabling the use of alginate and by increasing the ethanol tolerance. A cell-free approach was also considered, and a cascading enzymes reaction was designed to produce KDG, a precursor for bioplastic production, from alginate and laminarin, using different thermophilic enzymes. After fine tuning various enzymatic parameters, such as pH and temperature, KDG could be produced from alginate, but further optimizations are needed to produce it also from laminarin. In this context, a gene encoding a novel laminarinase was cloned and the recombinant enzyme characterized. Overall, this study is a proof of concept for brown seaweed valorization using metabolic engineering and paves the way toward a more sustainable world.
About the doctoral candidate
Antoine Moenaert was born in Ennevelin, a small village in North of France. He grew up with my two bigger sisters, Cecile and Emilie. Antoine completed his Master degree in Biotechnology at the University of Marseille, and as he didn’t want to continue with a PhD, he worked for two years in Basel, Switzerland. Looking for a change of environment, Antoine then moved to Iceland and joined Matís. He was supposed to stay for 6 months, yet, after 3 years working under great supervision, he decided to write a PhD application, which he is now ready to defend.
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Buses 14, 1, 6, 3 and 12 stop at the University of Iceland in Vatnsmýri. Buses 11 and 15 also stop nearby. Let's travel in an ecological way!