FT-IR spectroscopic characteristics of differently cultivated Bacillus subtilis

Bacillus subtilis is an aerobic endospore forming bacterium widely spread in different environments. Because it represents a biological agent of some health relevance, its rapid detection and identification is highly desirable. By using FT-IR spectroscopy for this purpose slightly different characteristics were obtained from cell mass grown in differently composed cultural media, and harvested in different phases of bacterial growth. If cultivated uniformly, i.e., 24 h at 30°C in a minimum-strength nutrient broth, cell mass of B. subtilis delivered a well differentiated spectrum with major absorption bands of nucleic acid structures at 3300 cm −1, cell wall constituents at 3000–2800 cm −1, proteinaceous structures at 1660, 1544 and 1235 cm −1, and some aliphatic structural units at 1080 cm −1. Attenuated total reflectance, and absorption/transmission scanning techniques, delivered structurally identical spectra but those obtained by the former technique were more expressed.