Insights on the downstream purification of fucoxanthin, a microalgal carotenoid, from an aqueous two-phase system stream exploiting ultrafiltration Alma Gómez-Loredo & José González-Valdez & Marco Rito-Palomares Received: 14 August 2014 /Revised and accepted: 19 October 2014 /Published online: 30 October 2014 # Springer Science+Business Media Dordrecht 2014 Abstract Alcohol–salt aqueous two-phase systems (ATPS) have shown promising results in the primary recovery of fucoxanthin from microalgae. However, the need of further operations to continue with the purification of the compound is required. In this sense, the use of ultrafiltration to process an ethanolic ATPS stream where fucoxanthin is recovered is explored in this work. Addition of ethanol to the original recovered ATPS ethanolic stream to a final relation of 74.15 % (w/w) resulted in the reduction of fucoxanthin unspe- cific losses in the membrane while incrementing its recovery. In fact, the ultrafiltration processing of the diluted ATPS sample presented a reduction of approximately 16 % of the proteic impurities, increasing product purity with a recovery of about 63 % of the compound in the permeate. These results show the potential of ultrafiltration in recovering molecules from ATPS streams in an easy-to-implement and economical manner avoiding a major setback in the industrial implemen- tation of this unitary operation. Keywords Ultrafiltration . Aqueous two-phase systems . Fucoxanthin . Microalgae . Isochrysis galbana Introduction Fucoxanthin is an allenic carotenoid that has shown to have an important nutraceutical bioactivity exerting antioxidant, anti- cancer, anti-diabetic, and anti-obesity effects in a variety of biological models (Miyashita et al. 2011). The recovery and purification of fucoxanthin from different marine sources has been studied, especially from brown algae (Roh et al. 2008; Kim et al. 2011; Noviendri et al. 2011; Shang et al 2011; Billakanti et al. 2013; Jaswir et al. 2011), but the costs asso- ciated with production and purification emergent technology equipment are the major drawback for its industrialization and commercialization (Guedes et al. 2011). Alternatively, fuco- xanthin extraction from microalgae has also been explored (Kim et al. 2012a, b; Xia et al. 2013) and it has been found that its concentration ranges from 2.24 to 18.23 mg g -1 dry weight (dw), which is one to three orders of magnitude greater than that found in macroalgae (Xia et al. 2013). With these excel- lent sources, there is now a growing need for low cost, simple and scalable strategies for the recovery of high value com- pounds such as fucoxanthin. In a previous study conducted in our research group (Gómez-Loredo et al. 2014), the use of alcohol–salt aqueous two-phase systems (ATPS) was addressed as a primary recov- ery technique for fucoxanthin contained in microalgal ex- tracts. In said study, we observed up to 70 % recovery of fucoxanthin and a removal of more than 60 % of other low molecular weight compounds, which comprised carotenoid and chlorophyll-related species. ATPS is a liquid–liquid frac- tionation technique based in the differences between the par- tition coefficients (K P ) of the species that are being separated (Rito-Palomares 2004). In this strategy, two liquids that are immiscible above a critical concentration (ethanol and a po- tassium phosphate solution in this case) are placed together and the solutes from a sample are expected to partition mainly to one of the two phases depending on the different physico- chemical interactions between them and the phase forming chemicals (González-Valdez et al. 2011). Although the use of ATPS rendered good recoveries of fucoxanthin in the top Alma Gómez-Loredo and José González-Valdez contributed equally to this work. A. Gómez-Loredo : J. González-Valdez : M. Rito-Palomares (*) Centro de Biotecnología-FEMSA, Tecnológico de Monterrey, Campus Monterrey. Ave. Eugenio Garza Sada 2501 Sur, 64849 Monterrey, NL, Mexico e-mail: mrito@itesm.mx J Appl Phycol (2015) 27:1517–1523 DOI 10.1007/s10811-014-0443-y Author's personal copy