The "string of pearl" colonies on nutrient agar is produced by
High-Yield Explanation
When Bacillus anthracis is grown on the surface of a solid medium containing 0.05-0.5 units of Penicillin/ml, in 3-6hours the cells grow large, spherical and in chains on the surface of the agar resembling a string of pearls. This string of pearls reaction clearly differentiates bacillus anthracis from Bacillus cereus and other aerobic bearers. Reference: Textbook of Microbiology; Anathanarayan and panicker's; 10th edition; Page no: 252