The public defence will be held as a video conference over Zoom.
The defence will follow regular procedure as far as possible, hence it will be open to the public and the audience can ask ex auditorio questions when invited to do so.
Due to copyright reasons, an electronic copy of the thesis must be ordered from the faculty. In order for the faculty to have time to process the order, it must be received by the faculty no later than 2 days prior to the public defence. Orders received later than 2 days before the defence will not be processed. Inquiries regarding the thesis after the public defence must be addressed to the candidate.
Digital Trial Lecture – time and place
- First opponent: Associate Professor Jette Feveile Young, Århus University
- Second opponent: Senior Research Scientist Hanne Haslene-Hox, Sintef Industry-Biotechnology and Nanomedicine
- Third member and chair of the evaluation committee: Professor Farrukh Abbas Chaudhry, University of Oslo
Chair of the Defence
Professor II Guttorm Haraldsen, University of Oslo
Professor Svein Olav Kolset, University of Oslo
The global population growth is posing enormous challenges to the sustainability of the current food production system. The average consumption of meat has tripled over the last 50 years, and meat consumption tends to rise as people get richer, threatening to make high-quality meat and animal protein products a limited resource. Conventional meat production is associated with considerable negative environmental impacts. Sustainable development approaches include achieving a responsible production, use, and consumption of meat products. Along with meat production, significant quantities of organic waste by-products related to environmental pollution are generated. These by-products contain high-quality proteins and nutrients that are currently underused. Opportunities to extract additional value from by-products and sustainable alternatives to conventional meat production should be studied and developed. A promising alternative to the traditional way of producing animal proteins is cultured meat. This meat bypasses animal production by growing muscle cells under a suitable cell culture medium in bioreactors and can potentially be produced more sustainable and efficient than conventional meat. Despite a high uncertainty due to the early developmental stage of the technology, life-cycle analyses suggest that cultured meat production requires 90% less land, 75% less water, 95% less eutrophication while contributing to 75% less greenhouse gas emissions. At the same time, cultured meat could provide an opportunity for a more responsible waste by-product management. However, there are major technological hurdles to overcome before cultured meat can be served at the dinner table, such as formulating a cost-effective serum-free media (SFM), developing suitable scaffolds necessary for muscle cell attachment, and optimizing a large-scale production.
By-products are low-cost, easy to obtain, food-safe ingredients with potential cell-stimulating and biocompatible properties. Therefore, they have excellent potential as ingredients in a tailor-made SFM and as muscle cell scaffolding support (microcarriers). In this project, the aim was to solve the challenges in cultured meat technology by investigating the feasibility of implementing by-products in the production process. Bovine skeletal muscle satellite cells (MuSCs) were isolated from Longissimus thoracis (beef sirloin). A scaffold-based design was implemented with microcarriers (MCs) providing permanent support to bovine skeletal muscle satellite cell (MuSC) monocultures in different sized bioreactors. Protein hydrolysates and edible MCs were produced from by-products, characterized, and evaluated for their cell growth-promoting efficiency. Further, long-term and scalable cell expansion parameters were investigated from low volume spinner flasks to higher volume bench-bioreactors.
The properties studied confirmed that various by-product hydrolysates and fractions effectively maintained cell growth in SFM. Further, the MCs produced using collagen extracted from turkey tendons, and powdered eggshell membrane (ESM) provided high cell culture expansion efficiency. After more than a month, MuSCs expanded in bench-bioreactors retained their proliferative and migratory capacity after dissociation from the MCs, indicating that the stem cell pool was well maintained. These are functional cell qualities essential for achieving the massive quantities of MuSCs required in cultured meat production. Also, low volume spinner flask cultures with less controlled environments were robustly reproducible in bench-bioreactors. Therefore, low volume spinner flasks can be used as higher throughput and scaled-down models to optimize MuSCs expansion on MCs. This work provides a promising start to develop a sustainable SFM for cultured meat production while reducing the problematic reliance on culture media cost drivers such as serum and commercial growth factors. More importantly, it contributes to a more responsible waste by-product management, representing a significantly more effective protein conversion strategy while contributing to a circular economy by reducing waste. Further, it was demonstrated that by-products with minimal processing successfully functions as MCs for bovine MuSCs in spinner flask culture. Finally, this work provides much-needed publicly accessible data on MuSCs growth kinetics, behavior, and development, especially in high volume bioreactors, and is a promising start to optimize cell expansion parameters adapted to muscle cells.
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