Why does this project matter?

The global chemical industry is under pressure to replace fossil-based feedstocks with renewable alternatives. Lignocellulosic biomass (LCB) – agricultural residues such as wheat straw, corn stover, and wood chips – is the most abundant renewable carbon source on earth. Yet its complex, variable composition challenges microorganisms: they must simultaneously cope with fluctuating sugar mixtures and toxic by-products from biomass pretreatment (furfural, HMF, phenolic compounds). Polyunsaturated fatty acids (PUFAs) are high-value targets from LCB – important as dietary supplements and as platform molecules for bio-based chemicals – but no microbial system has yet been engineered to robustly produce PUFAs from such heterogeneous feedstocks. This project addresses exactly this gap.

What are we aiming to achieve?

The central goal of P1 is to engineer two microbial hosts – the oleaginous bacterium Rhodococcus opacus PD630 and the cellulose-degrading myxobacterium Sorangium cellulosum – for tolerant and efficient PUFA biosynthesis from variable LCB feedstocks. Specific objectives are: (1) introduce and optimize a heterologous PUFA synthase system in R. opacus to achieve high PUFA titers; (2) expand the substrate range of both organisms to handle the diverse carbohydrate fractions of LCB; (3) engineer inhibitor tolerance against lignin degradation products; and (4) establish transferable strategies for rational strain design applicable beyond the two model organisms.

What will you work on as a PhD researcher?

As doctoral researcher in P1, you focus on engineering R. opacus PD630 into a robust, high-titer PUFA producer from LCB-derived feedstocks. You will first establishanalytical baselines for lipid analysis and fatty-acid profiling using GC or GC-MS before introducing a heterologous PUFA synthase gene cluster via molecular cloning and genome integration. Expression is optimized through metabolic engineering strategies such as promoter exchange and gene copy number variation.

A scientifically novel part of your work is characterizing the molecular mechanisms behind R. opacus' natural inhibitor tolerance. You design inhibition experiments with defined concentrations of lignin degradation products (furfural, phenol, vanillin) and identify responsible enzymes and regulatory networks using proteomic and transcriptomic tools. To push tolerance beyond natural limits, you apply Adaptive Laboratory Evolution (ALE) cultivating R. opacus under progressively increasing inhibitor stress and screening evolved strains for superior PUFA production. Your engineered strains and extracted lipids feed directly into P2 (bioprocess scale-up) and P3 (chemical hydrogenation).

Skills and methods you will develop during your doctorate:

• Genetic engineering of oleaginous actinobacteria (cloning, transformation, selection, metabolic engineering)

• Analytical biochemistry:GC and GC-MS

• Microbial physiology: growth kinetics, substrate utilization, inhibitor tolerance characterization

• Adaptive laboratory evolution and strain screening workflows

• Molecular biology tools: transcriptomics, proteomics (basics), bioinformatics for data interpretation

• Experimental design and statistical data analysis

• Scientific communication in an international, interdisciplinary team

Who will you work with and where?

The Winand group specializes in the genetic engineering of bacteriaas production hosts for high-value bioproducts, which is a field in which the group has published internationally recognized work. The laboratory is equipped for the complete genetic engineering workflow: molecular biology infrastructure, bacterial cultivation at multiple scales (microbioreactors, shake flasks, lab-scale bioreactors), and comprehensive analytics. Embedded in RTG TALENT, you gain access to a structured qualification program that combines advanced scientific training with transferable skills development, active exchange with academic and industrial collaboration partners, and tailored career support including the opportunity for a three-month placement in research, industry, or a start-up aligned with your career goals.