Performance comparison of downstream unit operations and process chains for the purification of amino acids for food, feed and pharma applications

Proteinogenic amino acids are important supplements in foods, feeds, and pharmaceuticals. However, the development of cost-efficient and scalable platform downstream processes for multi-ton manufacturing of amino acids is complicated by upstream process heterogeneity resulting in plethora of implementations at laboratory and industrial scale. Here, we review 18 unit operations and analyzed >50 downstream processes reported over six decades to compare separation performance, sustainability and costs, highlighting process advantages and limitations. We find that chromatography is used in >65% of downstream processes, achieving purities >98% in different setups. Sustainable and cost-effective alternatives seem to challenge this position. For example, membrane separations can achieve purities of 60-98% with reduced environmental footprint, costs, and additional options for process integration, mainly for acidic and basic amino acids. Crystallization is frequently used for formulation and purification if >50 g L-1 of amino acids with extreme pI are processed. Options to streamline current processes are discussed.