The fermentation of L-leucine by Brevibacterium flavum in 30 L bioreactor was investigated.The effects of initial glucose concentration and three glucose feeding strategies(intermittent glucose feeding,glucose-stat feeding and DO-stat glucose feeding) in fermentation process on biomass,yield of L-leucine,concentration of byprod-uct,and conversion rate were studied.The optimal concentration of initial glucose was 60 g/L and DO-stat glucose feeding was applied.According to the dissolved oxygen response signal,using feedback control,the feed rate in fer-mentation process was effectively manipulated and the accumulation of byproduct was reduced effectively.Biomass of 21.8 g/L dry cell weight could be obtained and the yield of L-leucine was 41.3 g/L,which were increased obviously.The glucose-limited fed-batch cultivation was achieved,and the conversion rate was 22.4%.