Sensing Penicillin: design and construction of Metabolite Biosensors

Abstract

Since decades microorganisms are employed in industrial biotechnology for the production of valuable compounds, ranging from vitamins to antibiotics and bioplastics. Among the microorganisms used, filamentous fungi are of special interest for the production of very small molecules, so-called ‘secondary metabolites’, as they can have antibiotic, antifungal, or antitumor activity. In recent years, significant progress was made in the genome engineering of fungi, thereby allowing us to produce secondary metabolites at large scale. However, the detection of new secondary metabolites as well as the identification of single fungal cells that produce them in high amounts remains challenging and limits the overall production of fungal secondary metabolites. Molecular biosensors represent an interesting tool to approach this bottleneck, as they can specifically recognize small molecules in- and outside of cells and send a signal after detecting the target molecule. There are many different ways how to develop biosensors for the detection of metabolites and the number of working biosensors is increasing steadily, especially for well-studied microbes, such as the bacterium E. coli. However, there are no biosensors for the detection of secondary metabolites produced by filamentous fungi yet. In this thesis, we explored how biosensors can be constructed for the detection of the fungal metabolite penicillin G, one of the most important antibiotics worldwide. New strategies for the development of nucleic acid-, protein- and whole cell-based biosensors were investigated, thereby laying an important first step to improve the detection of fungal secondary metabolites in the future.