Centrifugal partition extraction, a new method for direct metabolites recovery from culture broth: case study of torularhodin recovery from Rhodotorula rubra.

Centrifugal partition extraction (CPE), close to centrifugal partition chromatography, put in contact in a continuous way two immiscible liquid phases. This work presents early experiments on CPE use for solid-liquid-liquid extraction. It was applied to the direct treatment of culture broth for metabolites recovery. Torularhodin is one of the carotenoid pigments produced by the yeast Rhodotorula sp., with a terminal carboxylic group considered nowadays as a powerful antioxidant to be included in food and drugs formulations. Torularhodin was extracted from Rhodotorula rubra ICCF 209 cells by CPE. The recovery of torularhodin reaches 74 μg/g of biomass i.e. 294 μg/L of culture medium. The efficiency of the extraction step increased with the operating flow rate. The extraction yield could reach 91% with a contact time lower than 2 min. A 300 mL apparatus allowed a feed at 90 mL/min. The technique is proposed for extraction or sample preparation before analysis.