Technische Universität Wien

Ever since the potential of inclusion bodies (IBs) has been recognized, substantial advances have been made towards understanding IB processes and enabling efficient and controlled development strategies. Still, the influence of the chosen upstream processing (USP) strategy on the properties of inclusion bodies (IBs) and their refolding performance remains poorly understood. This work aims to target this challenge by investigating the influence of two chosen USP parameters, namely the specific substrate uptake rate and the temperature during induction, on IB titer, IB properties, namely IB purity, size and secondary protein structure of the IBs, as well as refolding yield of single-chain variable fragment M (scFvM) IBs. Contrary to findings in the literature, USP conditions neither had a statistically significant effect on the aforementioned IB properties nor on the refolding yield, but could clearly alter the IB titer. Our results provide detailed analytical insights on the independence of IB properties from USP conditions for this protein, while increasing the volumetric IB productivity proved feasible through variations in USP parameters. Therefore, titer maximization appears to be the sole optimization strategy for scFvM IBs and these findings may also apply to other target proteins with similar structural properties.

The fight against climate change requires consideration of carbon as a critical parameter in production systems, with the ultimate aim of creating a truly sustainable circular carbon economy. In this context, microbial bioproduction systems are a promising route to renewably generate value-added chemicals and fuels. Methanol and formate have recently gained interest as microbial one-carbon feedstocks, which can be produced sustainably from carbon dioxide and renewable energy, are easy to store and transport and readily dissolve in aqueous solutions. Acetogenic bacteria are strictly anaerobic microorganisms that can grow autotrophically on molecular hydrogen or use methanol, formate, and carbon monoxide as their sole carbon and energy sources via the Wood-Ljungdahl pathway, the most energetically efficient carbon fixation pathway known to date. Here, known variants of the Wood-Ljungdahl pathway, the physiology of a selection of methylotrophic and formatotrophic acetogens, and emphasize recent advancements in bioprocessing with respect to quantification of acetogen metabolism of methanol and formate as well as research aiming at establishing novel bioprocesses are reviewed. Additionally, the tools available for physiological and metabolic studies as well as for metabolic and genetic engineering are discussed. Finally, the features and constraints that govern the bioenergetics and stoichiometry of acetogen metabolism during growth on methanol and formate are reviewed, and future perspectives of the field discussed. The high energetic efficiency with which acetogens can convert methanol and formate into products renders them highly attractive platform hosts in the circular carbon economy.

Osteosynthesis screws are critical in orthopaedic surgery for stabilizing and aligning bone fracture fragments. Despite their importance, screw failure remains a significant complication, often due to excessive movement at the implant-bone interface resulting from both physiological loading and external mechanical forces. This study aims to enhance understanding of screw failure mechanisms by investigating the relationship between peri-implant CT-based trabecular bone morphology and screw failure under axial-, shear-, and mixed loading conditions, including the effect of plate elevation. Using high-resolution micro-computed tomography (micro-CT) and mechanical testing, 100 porcine epiphyseal bone samples were extracted and analysed to measure key CT-based trabecular morphometric indices and correlate them with mechanical failure. The study tested screws under ten different loading configurations. Statistical analyses revealed that bone volume (BV) and bone volume over total volume (BV/TV) are strong predictors of screw failure force, explaining 70-90 % of the variance in failure forces across different loading scenarios. The findings suggest that BV and BV/TV can be used to determine optimal screw implantation sites based on local bone morphology, potentially improving surgical outcomes and reducing postoperative complications. This research contributes to a more comprehensive understanding of orthopaedic screw behaviour and offers a predictive model for clinical use.