Abstract: The Plackett-Burman design was applied in cooperation with the single factor test for rapid screening the medium components for L (+) lactic acid production by L.rhamnosus MEE539.The most significant influencing factors carbon and nitrogen sources were screened by the single factor test and then together with surfactant and minerals were investigated in the subsequent Plackett-Burman design. The analysis results demonstrated that glucose, molasses, yeast extract, corn steep liquor, Tween80 and MnSO4 have the greatest impacts on the lactic acid production at a statistical confidence greater than 95% from 27 variables. In the present work, it was evident that the cooperation between Plackett-Burman design and single factor test allowed the quick identification of the most significant medium components for lactic acid production. Furthermore, this method proved to be useful in saving the researchers’ labor and reducing the errors occurred in the process of making medium.

Key words: Lactobacillus rhamnosus, medium components, Plackett-Burman design, single factor test