RESUMEN
The essential medium of B115 composed of 1% tryptone, 0.25% yeast extract and 0.5% sodium chloride was determined by using an orthogonal design. The orthogonal design was also employed in testing the optimum additions. It was composed of 0.1%(NH_(4))_(2)SO_(4),1.4%K_(2)HPO_(4), 0.6% KH_(2)PO_(4) and 0.1% (Na_(3)C_(6)H_(5)O_(7)). The yield of B115 cultured in optimum medium was compared with the one in essential medium. Statistic analysis showed that the growth of B115 was most significantly improved by adding K~(+)、NH~+_(4) and (Na_(3)C_(6)H_(5)O_(7)) to essential medium. The antibacterial effect of Bacillus subtilis strain B115 on pathogenic Aeromonas was studied. The results showed different antibacterial effects of B115 on different aeromonads. There were obvious antibacterial effects on BSK-10 and CL990920, while no effect on the growth of TL970424.