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An executive master's programme thesis from Aalborg University
Book cover


Optimized production and prebiotic uses of sulfonolipids

Author

Term

4. term

Publication year

2026

Submitted on

Abstract

Inflammatory bowel disease (IBD) causes long‑lasting inflammation in the digestive tract and affects about 2.5–3 million people in Europe. Both genes and changes in the gut microbiome—such as altered microbial diversity, sulfur metabolism, and the presence of specific bacterial groups—are thought to contribute. Because the microbiome can be shaped by diet, diet and prebiotics are promising ways to support gut health. This study examines sulfonolipids (Sols), sulfur‑containing lipids, as potential anti‑inflammatory molecules, and investigates how to produce them and how they affect gut microbes. We optimized Sol production using the bacterium Flavobacterium johnsoniae grown in CYE medium with 0.5 g/L cysteate, which increased both biomass and Sol yield. The Sols made by this bacterium resembled those found in Alistipes, a bacterial genus associated with the human gut. To test their effects, we added extracted lipids to pooled human stool samples in the lab. Sol supplementation markedly increased hydrogen sulfide (H2S) production but did not consistently change levels of short‑chain fatty acids (SCFAs), based on measurements by capillary electrophoresis and quantitative NMR. Sequencing of the 16S rRNA gene showed no significant shifts in overall microbial diversity, and quantitative PCR indicated no change in the absolute abundance of Alistipes. Overall, under the tested conditions Sols influenced microbial metabolism—especially by raising H2S—but did not substantially alter microbiome composition or SCFA production.

Inflammatorisk tarmsygdom (IBD) giver langvarig betændelse i mave‑tarm‑kanalen og rammer cirka 2,5–3 millioner mennesker i Europa. Både gener og ændringer i tarmens mikrobiom—som ændret mikrobiel diversitet, svovlstofskifte og forekomst af bestemte bakteriegrupper—menes at bidrage. Fordi mikrobiomet kan påvirkes af kost, er kost og præbiotika lovende strategier til at styrke tarmens sundhed. Dette studie undersøger sulfonolipider (Sols), svovlholdige lipider, som mulige anti‑inflammatoriske molekyler, og ser på både deres produktion og deres effekt på tarmmikrober. Vi optimerede Sol‑produktion ved at dyrke bakterien Flavobacterium johnsoniae i CYE‑medium tilsat 0,5 g/L cysteat, hvilket øgede både biomasse og Sol‑udbytte. De Sols, denne bakterie dannede, lignede dem, der ses hos Alistipes, en bakterieslægt forbundet med menneskets tarm. For at teste effekterne tilsatte vi ekstraherede lipider til sammenblandede menneskelige afføringsprøver i laboratoriet. Tilsætning af Sols øgede markant dannelsen af svovlbrinte (H2S), men ændrede ikke pålideligt niveauerne af kortkædede fedtsyrer (SCFA), målt med kapillærelektroforese og kvantitativ NMR. Sekventering af 16S rRNA‑genet viste ingen væsentlige ændringer i den samlede mikrobielle diversitet, og kvantitativ PCR viste ingen effekt på den absolutte mængde af Alistipes. Samlet set påvirkede Sols mikrobiel metabolisme—særligt ved at øge H2S—men ændrede ikke i nævneværdig grad mikrobiomets sammensætning eller SCFA‑produktionen under de testede betingelser.

[This abstract has been rewritten with the help of AI based on the project's original abstract]