Yielding ¦Â-carotene Red Yeast (rhodotorula Glutinis)

In this paper, we isolated a carotenoid hyproducing red yeast strain ns-1. Its content of carotenoid can reached 1358 g/g. Our research was developed in these four area: the composition of its pigments, the identification of strain ns-1, the optimum fermentation conditions of strain ns-1, and the method to screening carotenoid hyproducing strains.The composition of pigments in strain ns-1 was analyzed by reversed-phase HPLC. The result showed that P -carotene was in the majority of total extraction and it comprised 70.52% of the total pigment mixture. 3 -carotene was expected to the most promising food addiitive and vitamin.The strain ns-1 was identified with polyphasic taxonomic methods, comprised morphological and cultural characteristics, physiological characteristics, fatty acid composition and phylogenetic tree based on ITS rDNA sequences. The results indicated strain ns-1 belonged to Rhodotorula glutinis var daimensis. This species is not considered to be a human pathogen.The courses of fermentation and optimum fermentation conditions were studied in the strain ns-1. The pigments of strain ns-1 were accumulated at the end of exponential phase and the stationary phase. The best carbon source and nitrogen source was sucrose and pepton respectively. The most suitable temperture was 28 C. The constant pH and suitable ventilation was helpful to growth and carotenoid accumulation of strain ns-1. The corn starch lysised with amylase could be the good substitute for carbon source. The optimum fermentation conditions for carotenoid production were as follows: 1L corn starch lysised with amylase using 15g (NH4)SO4 , pH not control,inoculum size 50ml/L, shake frequency 450 r/min,aeration size 6L/min and culture tune 72h at 28C. The cell biomass, carotenoid contend and yield of strain ns-1 could reach 16.9g/L, 1089.3 u g/g and 8.4mg/L under the selected optimum conditions.These data were so high that not reported.By clarifying the matters that carotenoids play an antioxidant role in cytoplasm of strain ns-1: The more carotenoids it contains the higher ability as antioxidant it has. Therefore, strain ns-1 was treated with Toluidine blue (TBO), which can generate O?" on the surface of cell, to screen carotenoid-hyerproducing strains. The carotenoid content could reach 1740.9 g/g~ 2039.2 g/g ,which was 28.2%~50.1% higher than untreated cultures.This method can beapplied to screening carotenoid hyproducing strains in the future.