CITE seminar series

CITE - Chemicals In The Environment - is a research topic within the Helmholtz programm oriented funding. CITE addresses multiple aspects of the impact of chemicals in the environment. The seminar series (irregular) with invited external speakers aims to reflect these different aspects.

Scheduled seminars

Date: Tuesday, 13. September 2016, 03:30pm, lecture hall of building 4.0

Presenter: Dr. Michael Sander from ETH Zurich

Title: "Going large: On the reactivity and transformation of (bio-) macromolecules in natural and engineered systems"

Host: Prof. Dr. Kai-Uwe Goss

Abstract: Environmental organic chemistry and analytical chemistry have traditionally focused on elucidating the distribution and transformation of low molecular weight organic chemicals including compounds of technical use, agrochemicals, personal care products, and pharmaceuticals. By comparison, the environmental chemistry of (bio-) macromolecules has received much less attention - in part due to analytical challenges - and, as a consequence, remains only poorly studied and understood. This stands in contrast to the fact that many (bio-) macromolecules are of environmental concern and/or of biogeochemical importance. These molecules are ubiquitous in both natural and engineered systems and include - but are not limited to - natural organic matter, agrochemical bioregulators, enzymes, nucleic acids, viruses, and synthetic organic polymers.

This contribution will provide a brief overview of our past and ongoing work in this new field of environmental (bio-) macromolecular chemistry. The experimental, methodological and conceptual challenges of working with macromolecular (‘polymeric’) organic substances in water and soil systems will be highlighted by two illustrative examples. The first example will focus on the redox properties and reactivities of natural organic matter, as assessed by mediated electrochemical analyses. The importance of electron transfer to and from natural organic matter will be discussed in the context of carbon cycling in northern peatlands. The second example will be on the biodegradation of polyester-based polymers in soils. The key steps in the overall biodegradation process (i.e., enzymatic hydrolysis of the polyesters, microbial utilization of released oligo- and monomers, and incorporation of polymer carbon into microbial biomass) will be addressed. Novel experimental methodologies developed to study polymer biodegradation will be presented, including the use of 13C-labeled polymers for automated analysis of polymer mineralization and subsequent analysis of biomass incorporation using nanoscale ion secondary mass spectrometry.