The single factor and orthogonal tests were used to optimize the fermentative culture media of Serratia marcescens screened from the saline-alkali soil in Dongying City,Shandong Province,and the study on pilot-plant test in 100 L fermentation tank was made.It is shown from the test results that the optimal culture medium ingredients are glucose 10 g/L,(NH_4)_2SO_4 5 g/L,wheat bran 50 g/L,trisodium citrate 1.0 g/L,K_2HPO_4·3H_2O 0.3 g/L,FeSO_4·7H_2O 0.05 g/L,MgSO_4·7H_2O 0.5 g/L and pH(7.2)~7.7,and the optim...