From dirty soups to starter cultures: why I'm pursuing a PhD in sustainable food fermentation.

By Louka Cox

The first time I looked into a bubbling bioreactor filled with green algae and fungal mycelium, I felt a spark, the kind of excitement that only comes when science, sustainability, and purpose align. It was during my internship at Mycorena in Sweden, where I worked on developing circular food production processes using Chlorella vulgaris and filamentous fungi. I realized that I wanted to continue my career in advancing sustainable food systems. Today, that spark has evolved into a drive to pursue a PhD that dives deeper into fermentation and hybrid food innovation. Before I explain more about my PhD, I would like to take you back to where it all started.

My fascination with food and science started early. As a child, I would experiment in my grandma’s kitchen, mixing strange ingredients into “dirty soups” and proudly serving them to my grandpa, who always played along. Spending time in the garden, picking fruits and vegetables, helped me feel connected to the natural world, the source of everything we eat. In high school, that curiosity grew as I began to grasp the mechanisms of biology and chemistry. I still remember the excitement of finally understanding genetics and solving mole equations, it felt like unlocking a new language. I was eager to use this knowledge to better understand something deeply personal: my own body, and how it connects to the systems around us.

During my bachelor’s in Applied Biomedical Laboratory Research at Hogeschool Utrecht, I had a turning point. I realized I didn’t want to focus on treating symptoms through medicine, I wanted to address the root causes of the challenges we face, particularly climate change. I remember thinking: if we can heal the environment, we can also heal ourselves. Our microbiome is like a biodiverse forest, a complex, interconnected ecosystem that thrives when the world around them is healthy. These tiny agents of change fascinated me, not just for their biological intricacy, but for the possibilities they offered in creating meaningful, tangible solutions. Still, I wasn’t sure how or where I wanted to apply that passion.

That’s when I chose to pursue a master’s in biotechnology. I quickly gravitated toward an area close to my heart: food! Particularly, fermentation, felt like home. I used to make sauerkraut with my grandma, and my mother experimented with making her own wine. Fermentation felt like it was part of my roots, and more than that, it was directly connected to one of the biggest contributors to climate change: our food system. Although some forms of fermentation, like the digestive process in livestock animals, can contribute to rising greenhouse gas emissions, other forms help with mitigating food waste and producing sustainable foods, fuels, and materials. Tackling both food and sustainability at once felt like the perfect intersection of purpose and passion.

A crucial moment came during my thesis, in which I investigated the relationship between growth rate and bacterial microcompartment assembly in Propionibacterium freudenreichii. Known for its role in cheese production and potential probiotic functions, this bacterium stimulated my curiosity, not just for its metabolic flexibility, but for its potential in creating functional, flavorful foods. My research, conducted in chemostat cultivation systems, offered a window into the precision and creativity required in microbial design.  Around that same time, I was also inspired by a fellow student’s project that explored the development of a hybrid cheese made with both dairy and pea protein. Hybrid foods, especially when developed with fermentation, offer exciting opportunities to combine the best of both worlds: the functionality and flavor of dairy with the sustainability of plant-based ingredients. This project broadened my knowledge in nutritional enhancement, including enriching iron and protein content, and validating the final product through sensory evaluation.

Outside the lab, my passion for fermentation continued at home through small-scale experiments with kombucha, kimchi, and sourdough. Studying abroad not only introduced me to new foods, but it also gave me the opportunity to create a social network outside my close circle of family and friends at home. After my internship in Sweden, I gained skills and a network that helped me with securing a PhD position at Chalmers University.

Feeding the future: how fermented dairy-plant based hybrid foods can bridge the gap between planetary health and human nutrition.

As our global population grows and the climate crisis intensifies, the way we produce and consume food needs to change fast. One of the most urgent transitions we face is shifting our protein sources from predominantly animal-based to more plant-based alternatives. This isn’t just about personal choice or dietary trends; it’s about environmental necessity and long-term public health. Animal-based food production is a major contributor to global greenhouse gas emissions, land degradation, and water use (Carlsson Kanyama et al., 2021). In contrast, plant-based food systems require fewer natural resources and emit less CO₂. At the same time, diets richer in plant-based foods are associated with better health outcomes, thanks to their higher fiber content and lower levels of saturated fats (Willett et al., 2019).

But replacing animal proteins entirely isn’t always straightforward. Many plant-based proteins present challenges, they can have off-flavors (like the well-known “beany” or “grassy” taste), lower solubility, and contain anti-nutrients that reduce the bioavailability of essential minerals. This often results in lower consumer acceptance, especially when it comes to flavor and functionality (Onwezen et al., 2021).

In my PhD project, I’m exploring the potential of innovative fermented hybrid foods that combine both plant and animal proteins to create products that are more sustainable than conventional animal-based foods, but also more familiar and acceptable to consumers than fully plant-based alternatives (Olivas et al., 2024). In my research, I’m working specifically with dairy proteins and combining them with proteins from cereals or legumes. Through fermentation, these hybrid mixtures can be enhanced in terms of nutritional value, flavor, and functionality (Canon et al., 2022). Microorganisms play a key role here, because they can transform anti-nutrients and off-flavors into more desirable compounds while simultaneously producing aromas that improve taste and sensory experience (Genet et al., 2023). Hybrid foods can also help to enhance the solubility and functionality of plant proteins, making them behave more like their animal-based counterparts in food applications (Alves & Tavares, 2019).

The long-term goal of this research is twofold. First, to increase the availability of plant-based ingredients for environmentally conscious consumers who still value traditional, nutritious, and tasty foods. And second, to prepare the food system for future innovations like precision fermentation, where animal proteins are produced directly by microbes. Fermented hybrid foods may serve as a steppingstone, broadening the target consumer group and accelerating this protein transition. With the skills I developed during my master’s in biotechnology, from studying microbial metabolism to optimizing fermentation processes, I’m excited to explore these interactions in depth. Ultimately, I hope this research will bring us closer to a future where nutritious, sustainable, and delicious food is not a compromise, but the new standard.

References

Alves, A. C., & Tavares, G. M. (2019). Mixing animal and plant proteins: Is this a way to improve protein techno-functionalities? In Food Hydrocolloids (Vol. 97). Elsevier B.V. https://doi.org/10.1016/j.foodhyd.2019.06.016

Canon, F., Maillard, M. B., Famelart, M. H., Thierry, A., & Gagnaire, V. (2022). Mixed dairy and plant-based yogurt alternatives: Improving their physical and sensorial properties through formulation and lactic acid bacteria cocultures. Current Research in Food Science, 5, 665–676. https://doi.org/10.1016/J.CRFS.2022.03.011

Carlsson Kanyama, A., Hedin, B., & Katzeff, C. (2021). Differences in environmental impact between plant-based alternatives to dairy and dairy products: A systematic literature review. Sustainability (Switzerland), 13(22), 12599. https://doi.org/10.3390/SU132212599/S1

Genet, B. M. L., Sedó Molina, G. E., Wätjen, A. P., Barone, G., Albersten, K., Ahrné, L. M., Hansen, E. B., & Bang-Berthelsen, C. H. (2023). Hybrid Cheeses—Supplementation of Cheese with Plant-Based Ingredients for a Tasty, Nutritious and Sustainable Food Transition. In Fermentation (Vol. 9, Issue 7). Multidisciplinary Digital Publishing Institute (MDPI). https://doi.org/10.3390/fermentation9070667

Olivas, E. H., da Silva Padilha, M. P., & Comunian, T. A. (2024). The future of hybrid foods: trends, technology and strategy for sustainable and novel food development. International Journal of Food Science & Technology, 59(11), 8615–8617. https://doi.org/10.1111/IJFS.17443

Onwezen, M. C., Bouwman, E. P., Reinders, M. J., & Dagevos, H. (2021). A systematic review on consumer acceptance of alternative proteins: Pulses, algae, insects, plant-based meat alternatives, and cultured meat. Appetite, 159. https://doi.org/10.1016/J.APPET.2020.105058

Willett, W., Rockström, J., Loken, B., Springmann, M., Lang, T., Vermeulen, S., Garnett, T., Tilman, D., DeClerck, F., Wood, A., Jonell, M., Clark, M., Gordon, L. J., Fanzo, J., Hawkes, C., Zurayk, R., Rivera, J. A., De Vries, W., Majele Sibanda, L., … Murray, C. J. L. (2019). Food in the Anthropocene: the EAT-Lancet Commission on healthy diets from sustainable food systems. Lancet (London, England), 393(10170), 447–492. https://doi.org/10.1016/S0140-6736(18)31788-4