Extraction and characterization of R-phycoerythrin from wet and lyophilized macroalgae Solieria filiformis by pressurized water method

The present study evaluated the production of R-phycoerythrin (R-PE) extracted from the macroalgae Solieria filiformis through a green technology (pressurized water method). The extraction process over time and the macroalgae structure were analyzed. Two samples (freeze-dried and wet biomass, with 1 % and 10 % m/v, respectively) were studied at pressures up to 500 bar. R-PE maximum yield was reached for lyophilized seaweed structure after 360 min, obtaining 0.67 mg of R-PE per gram of dry biomass. In contrast, wet biomass reached 0.05 mg of R-PE per gram of wet biomass. Crude and precipitated extracts were characterized using the following techniques: electrophoresis, circular dichroism, and FTIR. The carbohydrate content was also determined. The biomolecule showed R-PE characteristic spectra, fluorescence, and α-helix structure as the main element of its secondary structure (93.28–95.24 %), indicating the presence of other proteins in the precipitated extract. Precipitated extract's cytotoxic activity was assessed through an MTT assay against tumor cell lines of colorectal cancer (HCT116), prostate cancer (PC3), glioblastoma cancer (SNB-19), and HL60 (promyeloblast leukemia). The most prominent in vitro results were in HL-60 and HCT-116 cell lines. •R-PE water pressurized extraction (at 500 bar) preserved the biofunctionality of biomolecule.•The lyophilization pre-treatment increased total protein concentration and R-PE yield.•R-PE structure was determined by different techniques.•The precipitated extract showed in vitro anticancer activity for leukemic cells (HL60).