Climate change and resource depletion create a pressing need to transition to a more sustainable bioeconomy. While the chemical industry plays an important role in modern society, its heavy reliance on fossil resources leads to significant environmental challenges. Biobased chemicals offer a promising alternative to increase sustainability, where organic acids are key platform chemicals, used for various applications like food and feed, pharmaceuticals, and bioplastics. However, their fermentative production is often constraint by energy-demanding purification processes with limited sustainability.

This doctoral research targets this bottleneck by developing innovative and intensified production processes for organic acids based on low-pH fermentation, which allow to avoid neutralisation and excessive waste generation. A key strategy explored is in situ product recovery (ISPR), where organic acids can be continuously removed during fermentation. This leads to reduced product inhibition and improved overall fermentation performance. This approach was particularly successful for hydrophobic organic aids as demonstrated for muconic acid, an upcoming platform chemical. For more water-soluble organic acids like lactic acid, anion exchange technology was identified as an effective purification method to directly extract organic acids from complex fermentation broth.

Additionally, an innovative purification technology was developed, namely solvent-impregnated resins, which enables the extraction of a wide range of organic acids and other biobased chemicals. These resins combine high extraction efficiency with low energy and material requirements as well as high stability, making them a versatile and sustainable solution for purification.

Overall, this research identified promising intensification strategies and designed innovative, efficient purification technologies for varying organic acids based on their properties. Important progress in process performance was validated at lab scale for current low-pH fermentation strategies, offering solutions that could support the transition to greener industrial processes.