Malt extract (%w/v) Antibacterial activity (inhibition zone in mm)
  Bacillus pumilus Aeromonas formicans 
1.0 16.5 ± 0.76 20.2 ± 0.29
2.0 16.9 ± 0.87 20.6 ± 0.58
3.0 17.6 ± 0.76 20.8 ± 0.50
4.0 18.5 ± 0.50 21.4 ± 0.29
5.0 16.5 ± 0.50 18.5 ± 0.50
Table 6: Determination of optimum concentration of malt extract for antibiotic production by cup-plate method.