Optimization of culture media for production of L-lactic acid by Lactobacillus casei subsp. rhamnosus

Culture media composition of L-lactic acid fermentation by Lactobacillus casei subsp.rhamnosus was studied.By orthogonal test,the optimum combination of nitrogen resource were as follows:yeast extract 5g/L,peptone 15g/L and beef extract 15g/L.Tomato juice and Chinese cabbage juice were added into the culture media,the results showed that the concentration of L-lactic acid was the highest level when both of the dosage were 10%.The orthogonal test was also used to get the optimum composition of culture media,according to the experiments,optimized composition of culture media were that glucose 160g/L,yeast extract 5g/L,peptone 10g/L,beef extract 15g/L,Tween 80 1mL/L,tomato juice 5mL/L,Chinese cabbage juice 5mL/L.The maximum concentration of L-lactic acid was 143.6g/L with the yield 89.8%.