Concentration and pre-purification with ultrafiltration of a R-phycoerythrin solution extracted from macro-algae Grateloupia turuturu: Process definition and up-scaling

Grateloupia turuturu, an invasive red macro-alga, represents an unexploited important biomass. A potential use of this seaweed is the production of valuable molecules, such as R-phycoerythrin. Nevertheless, after R-phycoerythrin extraction, protein extract has to be concentrated and pre-purified, which is generally expensive and requires many stages. The present study deals with the feasibility to implement a single stage of ultrafiltration for this purpose.A membrane screening was first realized at a lab-scale (Amicon stirred cell) to determine a suitable membrane molecular weight cut-off and a material allowing an optimal concentration and pre-purification of R-phycoerythrin contained in a hydrosoluble extract. The best adapted membrane turned out to be a polyethersulfone 30 kDa one. An up-scaling methodology was then realized on a PCI Microlab40 pilot plant equipped with an industrial type polyethersulfone 25–30 kDa membrane. The results show that R-phycoerythrin was concentrated without denaturation and accumulation of undesired molecules. Ultrafiltration up to a volume reduction factor of 5 was effective for R-phycoerythrin concentration and pre-purification: 100% of R-phycoerythrin was recovered, 32.9% of other proteins and 64.6% of sugars passed through membrane. Based on these results, a techno-economic study was investigated on an ultrafiltration unit at an industrial scale.