Interdisciplinary PhD projects 2023

NovoStimAct – Plant Biostimulant Activity of Novel Bacterial Biosurfactants

Sandra Bredenbruch (Coordinator), INRES - Molecular Phytomedicine, Universität Bonn
Nina Stadler, Bioorganic Chemistry, HHU Düsseldorf

Funding period: 01.05.-31.10. 2023

Establishing sustainable agriculture is a process that poses special challenges. Measures must not only be effective, but also environmentally friendly. Biostimulants are an effective tool as they naturally favour plant and crop development by stimulating nutritional processes and tolerance to abiotic stressors. Biosurfactants, surface-active secondary metabolites of natural origin, combine several beneficial properties for plants and are commonly considered to be environmentally friendly, biodegradable and low to non-toxic.

In previous experiments, both a growth-promoting effect on plants and the production of surface-active substances could be observed for two bacterial isolates. In this mini-project, these substances will be analysed in more detail. The analysis includes the characterisation of the molecular structures, as well as a basic evaluation of their suitability as biostimulants for sustainable plant production.

Abbildung: Joana Pohlentz

ReCHARM - Recycling of Ustilago maydis Cell Debris into Biochar for Soil Amelioration

Katharina Miebach (Coordinator), AVT-Biochemical engineering, RWTH Aachen
Joana Pohlentz, Microbiology, HHU Düsseldorf
Alexandra Brautlacht, Technology of energy raw materials, RWTH Aachen

Funding period: 01.04.-30.09.2023

The smut fungus Ustilago maydis is currently generating increasing interest in terms of biotechnological applications, as evident by the funding of several past and on-going BioSC projects. Both, natural and heterologous products synthesized by this fungus range from bulk chemicals like itaconic acid, microbial single-cell-oil and glycolipids to expensive pharmaceutical proteins or sesquiterpenes. Moreover, due to its plant-pathogen origin, U. maydis has an extensive enzyme set to degrade plant-based substrates. One yet unsolved problem in the application of U. maydis as a versatile compound producer is its robust and thick cell wall, making it difficult to disrupt cells after cultivation and to extract intracellular products. Hence, novel strategies towards efficient cell disruption will be evaluated. To be sustainable and environmentally friendly, enzymatic approaches will be established, avoiding harsh and toxic chemicals or energy intense treatments. A second bottleneck towards a sustainable and economic process is the lack of a circular process, in which culture remnants, like cell debris and unused media components, are recycled after product removal. To create a circular value chain, we will process this biomass waste stream by pyrolysis, where volatile components are degassed and carbonaceous solids remain. These so called biochars have recently been promoted as a useful soil amendment with a multifunctional application. Thus, we will combine efficient cell disruption and recycling of waste streams from U. maydis cultivations to create additional value as a key step towards completion of sustainable, circular biotechnological approaches.