During her PhD studies, Ida Schnack Eg Gadegaard investigated the milk enzyme xanthine oxidase. Recent findings suggested that it may interact with substances in infant saliva and help control harmful bacteria in the mouth. Ida examined how the enzyme works alone and together with lactoperoxidase, another abundant milk enzyme, forming a system that produces antibacterial compounds.

Her research showed that xanthine oxidase is more widely distributed in milk than previously believed and that the enzyme system can reduce the growth of oral bacteria from infants. The study also revealed that the system can influence bacterial gene activity, pointing to a more complex role in shaping the early oral microbiome. These findings provide new insights into how milk may support microbial balance in infancy and could guide the development of future functional dairy products or infant formula.

The PhD study was completed at the Department of Molecular Biology and Genetics, Faculty of Natural Sciences, Aarhus University.

This summary was prepared by the PhD student.

Time: Monday, 20 October 2025 at 12:00.
Place: Building 1870, room 816, Faculty Club, Department of Molecular Biology and Genetics, Aarhus University, Universitetsbyen 81, 8000 Aarhus C.
Title of PhD thesis: Xanthine Oxidase in Bovine Milk –Characterisation, Antibacterial Functionality, and Oral Microbiota Modulation by the Xanthine Oxidase–Lactoperoxidase System.
Contact information: Ida Schnack Eg Gadegaard, e-mail: iseg@mbg.au.dk tel.: +45 26 39 90 66
Members of the assessment committee:
Professor Alan Kelly, Department of Food & Nutritional Sciences, University College Cork, Ireland
Professor Denis Sandris Nielsen, Department of Food Science, University of Copenhagen, Denmark
Professor Ditlev Egeskov Brodersen (chair), Department of Molecular Biology and Genetics, Aarhus University, Denmark
Main supervisor:
Senior Researcher Jan Trige Rasmussen, Department of Molecular Biology and Genetics, Aarhus University, Denmark
Language: The PhD dissertation will be defended in English

The defence is public.
The PhD thesis is available for reading at the Graduate School of Natural Sciences/GSNS, Ny Munkegade 120, building 1521, 8000 Aarhus C

C