(The) studies on production of carotenoids in rhodotorula glutinis

Abstract

Various aspects of carotenogenesis and lipogenesis in Rhodotorula glutinis have been invesitaged. At firs, a HPLC procedure has been developed that permits determination of carotenoids quantitatively and qualitatively. Based on this procedure, the kinetics of the formation of carotenoids and lipid were investigated depending on the nitrogen contents in batch cultivation. $\beta$ -Carotene was most the abundant in younger cultures and torulene and torularhodin in older cultures, in that order. It was found that carotenogenesis and lipogenesis were simultaneously occurred due to nitrogen depletion. The continuous cultivation of Rh. glutinis were conducted at the dilution rate D = 0.02 $hr^{-1}$ and 0.08 $hr^{-1}$ in nitrogen limited conditions, and we studied the effect of dilution rate on lipid content and carotenoid formation. Total amounts of pigment were higher at D=0.02 $hr^{-1}$ than those at D=0.08 $hr^{-1}$, and the proportion of each component of carotenoids was slightly changed depending on dilution rates. Lipid content was somewhat higher at D=0.02 $hr^{-1}$. To investigate effects of stresses which may initiate aging include chilling, starvation of nutrient other than nitrogen on carotenogenesis and lipogenesis, three kinds of harsh condition were introduced. Effects of temperature on these phenomena were markedly shown. Total carotenoid concentration markedly increased, and the proportion of torularhodin was increased up to 75\% in comparison with normal nitrogen limited cultivation when cells in logarismic phase were transferred to distilled water and added glucose to it, it also shown that carotenogenesis was induced and torularhodin was the most abundant. But, lipid content was rather lower in all of these cases.