Projects:
Modern Biotechnology requires very active and robust enzymes for a wide range of applications. The desired enzymes often have to function under very extreme conditions (i.e. high temperature, extreme pH, high solvent or salt concentrations, etc.). These biocatalysts are encoded by the DNAs of cultivated and non-cultivated microbes. Today the majority of all microbes on earth are still not cultivated. Only 1% of the available microbes can be cultivated. However, to unleash the vast potential of the cultivated and non-cultivated microbes we use metagenomics and other technologies. One of the main projects in the lab focuses on the isolation of genes encoding for novel biocatalysts or bioactive compounds with unusual properties that function under extreme conditions. We are very much interested in the isolation of enzymes such as lipases, and decarboxylases.
Furthermore we are interested in enzymes that are involved in cellulose degradation for the production of bioenergy and other enzymes linked to sugar modifications. For this purpose we develop novel screening protocols. All the identified enzymes are usually characterized in detail on a molecular and biochemical level.
Furthermore we are interested to increase our understanding on the molecular and ecological aspects of microbial life in biofilms. Within this project we use metagenome technologies to identify novel genes and bioactive compounds that interfere with biofilm formation. Biofilms are aggregation of microorganisms growing on solid surfaces, which can cause severe clinical and industrial damages. We are mainly interested to identify novel biomolecules and proteins that can be used to prevent growth of microbial biofilms. Here we focus on the isolation of enzymes that are involved in the degradation of N-acyl-homoserine lactones and other autoinducer related molecules.
Autoinducer are molecules used by bacteria for Quorum sensing. Using a very sophisticated screening technology for quorum quenching clones from soil metagenomes, we have been able to identify several proteins with strong effects of bacterial swarming, swimming and biofilm formation in P. aeruginosa and E. coli. The identified enzymes are characterized in detail and tested for their effects on biofilm prevention or biofilm detachment.
Within our third project we are focusing on a comparative genome and transcriptome analyses of selected Gram-negative bacteria with relevance to biotechnology and microbe- host interaction. These microbes are living together with eukaryotes as either beneficial symbionts or pathogens. Therefore we are very much interested in the mechanisms these microbes use to communicate (Quorum Sensing) with each other and or how they destruct bacterial and eukaryotic signaling molecules (Quorum Quenching). One of the microbes studied is the unique broad host range and nitrogen fixing symbiont Rhizobium sp. NGR234. The complete genome sequence has been published by our lab. A close relative, the strain the S. fredii USDA257, is also being sequenced by our lab. Furthermore we have established the genome sequence of Burkholderia glumae PG1 together with the IMET. Lastly, we are sequencing a novel Janthinobacterium species that was recently isolated. All these genome sequences are established as part of national/international collaborations together with the Göttingen Genome laboratory.
