In-Depth Functional Characterization of Bacillus subtilis PLSSC Revealing its Robust Probiotic Attributes - Abstract
Functional assessment of a probiotic strain is imperative to substantiate its potential to offer health benefits to the host upon adequate consumption. Present study was designed to study probiotic attributes, safety aspects of Bacillus subtilis PLSSC in vitro with detailed investigation on antimicrobial activity, aligned to the regulatory guidance. We found that Bacillus subtilis PLSSC spore powder preparation is stable at real time ICH stability conditions for 30 months (99.71% viability). It remained viable in acid and bile stress and during in vitro simulated gastrointestinal digestion (99.48-100% viability). It tolerated thermal exposure well up to 80°C (86.18 % viability) up to 6 h and survived (100.0% viability) pasteurization. It showed excellent aqueous stability under ICH recommended storage conditions for one year with 96.21-99.9 % survival. Cell surface adhesion properties indicated affinity towards non-polar solvents and ability to aggregate with pathogens. Bacillus subtilis PLSSC showed broad spectrum antimicrobial activity including anti-listerial with 125 mg L-1 MIC. Its antimicrobial compound identified as subtilosin A (3108 Da by mass spectrometry) showed good stability in broad pH range (1.0-11.0) and temperatures (40-100°C). Peptide was sensitive to pepsin treatment but remained stable when exposed to trypsin. Thus, it showed excellent in vitro probiotic potential with well characterized antimicrobial activity as well as suitability for industrial processing implying wide applications.