Citric acid bioproduction and downstream processing: Status, opportunities, and challenges

Citric acid (CA) has been widely used in different industrial sectors, being produced through fermentation of lowcost feedstock. The development of downstream processes, easier to operate, environmentally friendly, and more economic than precipitation, is certainly a challenge in CA bioproduction. Large volumes of by-products generated in precipitation require treatment before disposal. Adsorption, extraction, and membrane separation have been shown to have a lower environmental impact than precipitation, but the technological maturity of these methods is still limited. However, reactive extraction and adsorption have great potential for industrial applications. This review shows that there is still much to be explored, both about the factors that are intrinsic to the techniques, but also in their combination for new processes' development. This review reports the most recent advances on CA bioproduction, with significant information about recovery and purification methods involving this highly industrially demanded organic acid.

Automated summary

The review highlights the challenges in CA bioproduction, emphasizing the potential of reactive extraction and adsorption for industrial applications. While adsorption, extraction, and membrane separation have lower environmental impacts than precipitation, their technological maturity remains limited. New processes combining these techniques for CA recovery and purification still hold promise for further exploration.