Reactive extraction technologies for organic acids in industrial fermentation processes – A review
Sinah Tönjes, Evelien Uitterhaegen, Karel De Winter, Wim Soetaert
Abstract
• Reactive extraction for effective organic acid recovery from fermentation. • Process integration for intensified fermentation performance and sustainability. • Impact of fermentation parameters, broth composition, and solvent toxicity. • Internal and external set-ups and equipment for integrated reactive extraction. • Scalability and techno-economic considerations. Reactive liquid–liquid extraction is an attractive, innovative technique to intensify the fermentative production and downstream processing of biobased organic acids through a selective partitioning to an organic phase. In an in situ product recovery (ISPR) approach, fermentation performance can be enhanced by alleviating product inhibition, yielding a relatively concentrated product stream. While reactive extraction has been widely studied for different organic acids in dilute aqueous solutions, its application to complex product streams from fermentation brings important added challenges. This review addresses these challenges and offers perspectives for future research and scale-up studies towards industrialisation. The complex interplay of solvent systems, extraction behaviour of different organic acids, and fermentation-dependent parameters is critically reviewed. Additionally, challenges faced upon implementation in industrial set-ups are discussed with a specific focus on ISPR technologies, discussing back extraction and resource recycling, as well as techno-economic considerations. To that end, potential process strategies and future research directions are proposed to overcome remaining limitations to bring this technology to an industrial level.