PhD Defence by Suvasina Balasubramanian

Principal supervisor:

• Professor Peter Ruhdal Jensen

Co-supervisor:

• Professor Ivan Mijakovic

Examiners:

• Associate Professor Christian Solem, DTU Food
• Senior Department Manager Kenneth Jensen, Novonesis
• Professor Lars M. Blank, RWTH Aachen

Chairperson at defence:

• Associate Professor Christian Solem

Resume
In the quest to address growing global food demands and combat climate change, precision fermentation has emerged as a promising and sustainable solution for producing high-quality animal proteins without relying on traditional livestock farming. This innovative technology harnesses the power of microbes, such as bacteria, yeast and fungi, to produce specific food components, including proteins, enzymes, and flavor compounds, that can replace animal-derived ingredients.

Milk proteins, such as caseins and whey proteins, are among the most nutritionally and functionally important animal proteins. However, replicating their production in microbial systems presents significant challenges. These proteins have complex structures and often require precise post-translational modifications, such as phosphorylation, which are essential for their structure, functionality, and ability to interact with other food components. For example, phosphorylation in caseins is critical for their calcium-binding capacity and the formation of micelles, which contribute to the texture and nutritional value of dairy products like cheese and yogurt.

While precision fermentation is still in its early stages, with significant hurdles such as achieving cost-efficiency, scalability, and accurate replication of these modifications, its potential to revolutionize food systems is immense. By reducing reliance on traditional dairy farming, precision fermentation could dramatically lower greenhouse gas emissions, land use, and water consumption associated with animal agriculture.

This thesis explores microbial production systems for milk proteins using bacterial hosts. It investigates strategies to achieve phosphorylation of these proteins, either through genetic engineering or alternative approaches, to mimic the natural properties of animal-derived milk proteins. The goal is to develop sustainable, functional alternatives that match the quality of traditional dairy proteins, paving the way for environmentally friendly innovations in the food industry.

A copy of the PhD thesis is available for reading at the department.