Sardar Dipankar, Morol Istiaq, Bari Johra, Sarkar Amalan, Habib Adnan
Department of Biotechnology, Bangladesh Agricultural University, Mymensingh, Bangladesh.
Department of Microbiology and Hygiene, Bangladesh Agricultural University, Mymensingh, Bangladesh.
PLoS One. 2025 Jul 10;20(7):e0328216. doi: 10.1371/journal.pone.0328216. eCollection 2025.
Probiotics, particularly strains from the genera Bacillus, Lactobacillus, and Staphylococcus, play a vital role in gut health, immune modulation, and pathogen inhibition. However, environmental stressors during storage often compromise their long-term viability and probiotic functionality. By examining how lyophilization affects the viability and probiotic functionality of certain strains of Bacillus, Lactobacillus, and Staphylococcus, this study sought to understand how storage conditions and protective agents affect bacterial survival and important probiotic characteristics. The bacterial strains were isolated from the gastrointestinal tract of native chickens, cultivated in MRS broth, subjected to freeze-drying with different cryoprotectant formulations, and stored at varying temperatures (4°C, -20°C, and -80°C) for up to 12 months. Survival rates, stress resistance under simulated gastric and intestinal conditions, and probiotic functionality were evaluated over time. The results demonstrated that ultra-low temperature storage (-80°C) combined with a formulation of 5% glucose, 5% sucrose, 7% skim milk powder, and 2% glycine provided optimal protection. This combination effectively reduced oxidative and gastrointestinal stress and preserved key probiotic traits, including adhesion potential, antimicrobial activity, and metabolic stability. Conversely, strains stored without cryoprotectants or at higher temperatures exhibited significant viability loss and functional decline. The study highlights the critical role of optimized cryoprotection in maintaining probiotic efficacy during long-term storage. Our findings reinforce the necessity of selecting appropriate excipients and storage conditions to sustain probiotic efficacy, providing valuable insights for the development of stable, high-quality probiotic formulations. Future research should explore strain-specific responses to lyophilization and alternative preservation strategies to improve probiotic stability and performance.
益生菌，尤其是芽孢杆菌属、乳杆菌属和葡萄球菌属的菌株，在肠道健康、免疫调节和病原体抑制方面发挥着至关重要的作用。然而，储存期间的环境压力因素常常会损害它们的长期生存能力和益生菌功能。通过研究冻干如何影响某些芽孢杆菌、乳杆菌和葡萄球菌菌株的生存能力和益生菌功能，本研究旨在了解储存条件和保护剂如何影响细菌存活以及重要的益生菌特性。这些细菌菌株从本地鸡的胃肠道中分离出来，在MRS肉汤中培养，用不同的冷冻保护剂配方进行冻干，并在不同温度（4°C、-20°C和-80°C）下储存长达12个月。随着时间的推移评估存活率、模拟胃和肠道条件下的抗应激能力以及益生菌功能。结果表明，超低温储存（-80°C）与5%葡萄糖、5%蔗糖、7%脱脂奶粉和2%甘氨酸的配方相结合可提供最佳保护。这种组合有效地降低了氧化应激和胃肠道应激，并保留了关键的益生菌特性，包括黏附潜力、抗菌活性和代谢稳定性。相反，未使用冷冻保护剂或在较高温度下储存的菌株表现出显著的生存能力丧失和功能下降。该研究强调了优化冷冻保护在长期储存期间维持益生菌功效方面的关键作用。我们的研究结果强化了选择合适的辅料和储存条件以维持益生菌功效的必要性，为开发稳定、高质量的益生菌制剂提供了有价值的见解。未来的研究应探索菌株对冻干的特异性反应以及替代保存策略，以提高益生菌的稳定性和性能。
