Fig. (6) Characterization of purified mutacin(A) Chart of turbidimetric assay for the determination of the growth inhibitory effect of mutacin (100 ìg/ml) and ampicillin (100 ìg/ml) in LB medium for S. thermophilus, B. thuringiensis, and L. bulgaricus. (B) FTIR spectrum using Thermo – Nicolet 6700 system for mutacin lyophilized sample dispersed on KBr disk. Grey region (600−800cm-1) referred to the position where the expected peaks of R−S−R bonds should appear.