Effect of Ca~(2+), Mg~(2+), Mn~(2+) on Growth and Sporulation of Bacillus sp. L15

摘要

The Bacillus sp. L15 isolated from a sea cucumber Apostichopus japonicus breeding pond could effectively reduce the contents of COD and NH4-N in the pond water and significantly promoted the growth of A.japonicus. This study further tested the influence of Ca~(2+), Mg~(2+) and Mn~(2+) on the reproduction and sporulation of vegetative cells in the Bacillus sp. L15 through an orthogonally designed experiment. The three ion types showed different impacts on the reproduction and sporulation of Bacillus sp. L15 cells. The Ca~(2+) inhibited the reproduction of vegetative cells, but promoted spore maturation. The effect of Mg~(2+) and Mn~(2+) on vegetative cell reproduction and spore maturation depended on the range of ion concentration, and the optimal concentration for both ions promotion cell growth was 100 μg/L. This study suggests that the concentration of Ca~(2+), Mg~(2+) and Mn~(2+) should be all at 100 μg/L in the basic freshwater fermentation medium for the culture of Bacillus sp. L15.