Influence of Trace Metals Lons on Growth and Antifungal Activity of Bacillus Subtilis MHS15

The effect of divalent metal ions in cultivation medium was studied to improve the growth and antifungal activity of Bacillus subtilis MHS15. Two metals salts namely FeSO4. 7H2O and MgSO4.7H2O at concentrations of 1 and 2 mM have stimulated the growth when the maximum optical density of 2.137 and 1.993 were achieved compared with 1.929 for control. Optical density has been suppressed using MnSO4.H2O, CuSO4.5H2O and ZnSO4.7H2O. The MIC against Aspergillus niger observed using 1 mM FeSO4. 7H2O when the inhibition was 68.2% with an increase of 70.7% comparing with the maximum inhibition 48.2% by the control. Thus, the present study provides valuable information for enhancing growth and inhibitory effect of B. subtilis MHS15.