High-throughput screening of aqueous two-phase systems for polyphenol extraction from A. nodosum: a green chemistry approach

Brown macroalgae are an attractive third-generation feedstock of natural products, in order to design green chemistry-compliant processes and reduce the use of organic solvents in bioactive product extraction, aqueous two-phase systems (ATPS) was applied. This research aimed to develop a high-throughput screening (HTS) to recover polyphenols from Ascophyllum nodosum using ATPS. In total, 384 different 2-phase systems were assessed using an automated liquid-handling system to evaluate polyphenol recovery using a model system of phloroglucinol to establish an optimal 2-phase system for polyphenol partitioning. Various ratios of PEG:potassium phosphate solutions were explored to evaluate partitioning of polyphenols via a scale-down approach. Scale-down selected system showed a recovery of phloroglucinol of 62.9{+/-}12.0%, this system was used for scale-up trials. Scale-up studies confirmed that the HTS method was able to recover polyphenols with a 54.8{+/-}14.2% in the phloroglucinol model system. When the optimised ATPS system was tested with a polyphenol extract, 93.62{+/-}8.24% recovery was observed. When ATPS was applied to a fucoidan and alginate biorefinery residue, 88.40{+/-}4.59% polyphenol was recovered. These findings confirm that ATPS is a valuable addition to the bioprocess toolkit for sustainable extraction of natural products from macroalgae in a multiproduct biorefinery approach. Practical applicationSelection of the best concentrations of phase-forming components and recovery conditions for the application of aqueous two-phase systems in an industrial setup has been proved to be laborious and cumbersome. This paper presents an automated platform to rapidly assess several ATPS to recover polyphenols from brown macroalgae and a subsequent confirmation with the scale-up of the potential candidates and contrasted with two case studies. This methodology allows a quick screening for the best aqueous two-phase system and can be expanded to recover high-value products from other types of macroalgae or microalgae.