Development of a continuous aqueous two-phase flotation process for the downstream processing of biotechnological products

Aqueous two-phase flotation (ATPF) is an alternative downstream process for direct recovery of biotechnological products from crude biosuspensions. ATPF is a combination of two phase extraction and flotation, resulting in high recoveries and product concentrations. In addition to selecting a suitable two-phase system, the process design must be optimized to realize an efficient ATPF process. In this study, the focus was on the process strategy. As an example of a biotechnological product, the technical enzyme phospholipase was purified. The influence of different initial enzyme concentrations on the separation process was investigated and limitations of the separation efficiency were identified. Based on these findings, batch ATPF was transferred first to semicontinuous ATPF and later to continuous ATPF. Thus, this work describes for the first time a continuous ATPF, which showed 2.5 times the purification capacity of batch ATPF in the same flotation time.