Research

How bacteria degrade sugars

Our working group investigates how heterotrophic bacteria use complex sugars and how these processes influence their environment. The aim is to characterize the physiological capabilities of microbial communities (“phenotyping of microbiomes”) and to quantify the heterotrophy of microorganisms.
Simply put, we want to understand microbial cycling of sugars and what impact this has on ecosystems. Examples range from phytoplancton biomass (sugars) —with direct consequences for the global carbon cycle—to bacterial sugar utilisation in human and animal digestive systems, which can affect health.
We want to redefine the analysis of microbial heterotrophy by using innovative culture-independent methods to visualize microbial phenotypes. These include, for example, fluorescent substrates that allow the metabolic activities of individual bacteria to be observed directly. Our group combines approaches from molecular ecology (DNA extraction, PCR, diversity analyses using 16S rRNA, metagenomics, FISH, and microscopy), microbiology (cultivation, growth curves, metabolic analyses), and glycobiology (carbohydrate extraction, sugar analyses, production of fluorescent sugars).
We are an Emmy Noether Junior Research Group and part of the Critical Research Centre (SFB-TRR) CONCENTRATE and the Cluster of Excellence The Ocean Floor – Earth’s Uncharted Interface.

The 3 bacterial sugar degradation mechanisms in the ocean

In order to make complex sugars, known as polysaccharides, accessible for microbiological metabolism, they must be broken down into smaller components by enzymes. Marine bacteria process complex sugars in three different ways. Either they absorb the polysaccharides into their membrane space and break them down there without other microorganisms getting any of them. This mechanism is called “selfish.” Other bacteria release their enzymes into the environment, where they break down the sugars and make the products available to everyone. This benefits the last type of bacteria, which does not produce any enzymes and lives only on the breakdown products of others. You can imagine it a little like bacteria fighting over candy.

Where in the oceans do these mechanisms occur, and how are they related to the surrounding environmental factors? To understand the influences of temperature, depth, pressure, nutrient availability, oxygen, and salinity, we take seawater samples from various locations in the oceans.

Factors such as temperature and pH determine how well bacteria can absorb and utilize sugar and other organic substances. The aim is to gain a better understanding of the role of abiotic parameters in the interaction between carbon cycles and microbial dynamics in the marine ecosystem.

H?nde mit blauen Handschuhen, die etwas pipettieren.

Biotic factors originate from other living organisms. We want to understand how competition influences the type of sugar uptake. Co-cultures of different species should show us whether they react selfishly when they have neighbors.

Grün und glau leuchtende Bakterienzelle. Deutlicher egoistitsche Zuckerabbau.

Selfish bacteria could have an impact on carbon storage in the ocean, as they (temporarily) absorb sugar and thus remove carbon compounds from the cycle.

Our project is the continuation of the RUMIC Project (Marie Sk?odowska-Curie Actions, 2019–2023), which explored new strategies to specifically influence the rumen microbiome of ruminants through prebiotics. The goal is to improve the digestion of plant fibers, make fermentation more efficient, and thereby promote animal health and sustainability.

Key findings so far: