The transition towards climate-neutral and resource-efficient economy required innovative technologies for carbon capture and utilization. Carbon dioxide is an abundant and underutilized carbon source that can be transformed into valuable chemicals. The sustainable production of platform chemicals and alternative protein sources by utilizing carbon as a source from CO2 addresses two major challenges, 1) meeting the rising demand for sustainable protein and 2) decarbonizing the chemical industry. Recent advances in Biotechnology have shown the potential to convert CO2, air and renewable electricity into value-added compounds. While significant progress has been made in the bioprocess development, the downstream processing of produced microbial biomass into stable, high-quality product remains still a key bottleneck.

Spray drying is a scalable and energy efficient route to convert microbial biomass into powdered single-cell protein and has been largely studied for the production of large number of powders in food and pharmaceutical industries. However, the relationship between process parameters and final powder properties is not yet fully understood – particularly for a biomass derived from bio-electrochemical synthesis. Ensuring consistent powder characteristics is essential for its use in food and feed applications. This project addresses this gap by linking sustainable upstream CO2 conversion with robust downstream particle processing, thereby contribution to the development of an integrated and circular economy.

The aim of this project is to develop a robust and scalable spray drying process for converting microbial biomass into a high-quality, stable and application oriented single-cell protein powder starting with a laboratory mini spray drier (Büchi B-190 mini-spray drier) and later on scale-up the process using pilot-plant spray drier (Niro A/S Gladsaxevej 305) while maintaining the same powder characteristics. To achieve this, systematic experimental studies will be conducted scale where key parameters such as nozzle configuration, inlet and outlet temperature of the chamber, atomization pressure, feed rate are varied in a controlled manner and the resulting powders will be comprehensively characterized for PSD, density, flowability, morphology etc. Moreover, the powder is also subjected to protein characterization methods to determine its stability and denaturation. These insights will be used to establish a relationship between process conditions, material properties and product quality and further to implement these conditions in a pilot-scale for process scale-up.