Method for Torularhodin Separation and Analysis in the Yeast Rhodotorula Rubra Aerobically Cultivated in Lab Bioreactor

摘要

The paper presents a procedure realized for the extraction, separation, and quantitativerndetermination of the carotenoids, mainly beta-carotene and torularhodin, withrnantioxidant possible application, from the yeast Rhodotorula rubra ICCF 209. Thernprocedure was applied after the aerobic bioprocess completion. Wet biomass wasrnseparated by centrifugation at 8000 rpm and the total carotenoid pigments was carriedrnout by extraction with acetone-water and n-hexane, with all carotenoid pigments in thernupper hexane layer. The pigmented hexane layer was then washed with distilled water.rnThe optical density of the pigmented hexane filtrate was determined on a UV-VISrnspectrophotometer (Jenway Spectrophotometer) at 500 nm against a hexane blank torngive the total pigment concentration. The pigment torularhodin was separated from thernhexane by extraction with methanol potash (0.1 N) and the visible spectrum at 380-700rnnm was drawn to obtain the torularhodin concentration. A final concentration of therntotal carotenoids as beta-carotene of 250-450 μg/L medium and a concentration ofrntorularhodin of 140-350 μg/L was determined in case of the aerobic bioprocess in thern3.7 L Bioengineering AG lab bioreactor with mechanical stirring with a duration of 72rnhours. In the first 24 hours the beta-carotene was the major component of carotenoids,rnwhile after 48 hours it seems that more than 50% of this pigment is transformed intorntorularhodin via the metabolic pathway described in the literature.