Optimization of media of rhdotorula glutinis, a oleaginous yeast, in continuous culture

Abstract

Rhodotorula glutinis NRRL-Y-1091, a red oleaginous yeast, was grown in batch and continuous culture system. At batch culture, the accumulaion of lipid is favoured not only by nitrogen limitation but also by deficiency in magnesium and phosphate. It would appear from the above observations that any constraint which limits growth but not assimilation of the carbon source will tend to cause accumulation of lipid. At continuous culture, mass and energy balance method was used to analyze that the cell concentration decreased rapidly with increasing dilution rate. Energetic yield, $\eta$, decreased with increasing dilution rate, but metabolic heat fraction, $\epsilon$, increased with increasing dilution rate. Since $\eta + \epsilon$, is almost constant at all dilution rate experimented, it may be said that product formation may not be correlated with that result. Since in experiment, the dissolved oxygen concentration was maintained at 50\% at higher dilution rate, incomplete aeration and agitation were not correlated with that result. The medium may be inadequate in composition and preparation procedure. Therefore, medium optimization in continuous culture was carried out using a pulse method.