The effects of Na2SeO3 addition time and L-methione on the biomass,glutathione biosynthesis,intracellular glutathione content and selenium organic transformation rate during selenium-enriched Candida utilis preparation in a 5 L stirred fermentor were investigated.An effective culture strategy which involved L-methione addition at the beginning of cultivation(0 h) and Na2SeO3 addition after glucose consumption(15 h) was obtained with the aim of high organic selenium content and high intracellular glutathione content within the selenium-enriched C.utilis.Using this strategy,the selenium organic biotransformation rate can reach 87.5%.