Screening, Identification and Antibacterial Activities of Effective Thermotolerant Bacillus spp. Strains Isolated from Raw Milk

Abstract

Forty-one isolates of Bacillus species were isolated from raw milk, analyzed using the spot on lawn and agar diffusion method in terms of their general inhibition effects to test bacteria (Escherichia coli TISTR 887 and Staphylococcus aureus TISTR 517). The results demonstrated that most isolates are effective against Gram-positive and Gram-negative bacteria whereas their extensive inhibition effect is particularly against Gram-positive bacteria. Only 2 effective thermotolerant isolates, BA8 and BA16, exerted broad spectrum antibacterial activities against both test bacteria. Based on biochemical and physiological properties, they were classified as Brevibacillus laterosporus and Geobacillus thermoglucosidasius, respectively.

Keywords

• Bacillus species
• Escherichia coli
• Staphylococcus aureus