We generally distinguish between taxonomically specific molecules that characterize biomass of modern and ancient microorganisms, so-called lipid biomarkers, and intermediates and products of microbial metabolism, so-called metabolites. The group of lipid biomarkers is diverse and useful for many applications in geosciences and microbial ecology. Examples are intact polar lipids (IPLs – a term first coined by our group), i.e., the constituents of cellular membranes in all organisms, steroidal lipids, hopanoids, fatty acids, and straight-chain wax components of higher land plants. Representatives in the group of metabolites are volatile fatty acids such as acetic acid, methane, and low-molecular weight alcohols and amines. Concentrations and isotopic compositions of these compounds can provide useful information on the carbon flow regime in natural microbial ecosystems. Dedicated analytical instrumentation for studying these diverse components consists of combinations of gas- and liquid chromatographic systems and various types of mass spectrometers.
The group of lipid biomarkers is diverse and useful for many applications in geosciences and microbial ecology. Follow this link for more information on our analytical approaches to study intact polar lipids (IPLs), core lipids, and traditional biomarkers.
We study a range of low-molecular-weight compounds that act as central intermediates in metabolic processes, including volatile fatty acids (VFAs), volatile organic sulfur compounds, methane and other volatile hydrocarbons.
We study the molecular composition of DOM by ultra-high resolution mass spectrometry, i.e. Fourier Transform Ion Cyclotron Resononance Mass Spectrometry (FT-ICR-MS). This analytical technique is available through cooperation with Bruker Daltonik GmbH, Bremen.
Stable isotope probing
The stable carbon-13 isotope is rare in nature. Therefore, the addition of 13C-labelled compounds in incubation experiments, allows us to track the flow of carbon from substrates to metabolic products and new biomass. We will soon provide a link for more information on this technique.
Our analytical infrastructure consists of state-of-the-art instrumentation for detecting and identifying biomarkers, lipid membrane compounds, organic material and metabolites of microbial metabolism and is the base of our research.