Unveiling and understanding differences in physiological features below the species level may serve as an essential fast-screening tool for selecting strains that can promote a specific probiotic effect. To study the intra-species diversity of Bacillus, a genus with a wide range of enzyme activities and specificity, 190 Bacillus strains were isolated from traditional Korean fermented food products. Altogether, in the preliminary safety screening, 8 of these strains were found negative for lecithinase and hemolysis activity and were selected for further investigations. On the basis of different levels of enzyme functionalities (high or low proteolytic, amylolytic, and lipolytic (PAL) activities), two Bacillus subtilis strains were selected for an in vivo study. Each of the two strains was separately administered at a level of 1 × 10⁸ CFU per day to C57BL/6 mice that were fed 60% high-fat diet ad libitum for 8 weeks, while Xenical, an anti-obesity drug, was used as a positive control in the experimental setup. B. subtilis M34 and B. subtilis GS40a with low and high amylolytic activities, respectively, induced significantly different and contrasting physiological effects. The production of short-chain fatty acids appeared to be closely associated with a shift in the gut microbiota.

揭示和了解低于物种水平的生理特征差异可能是一种重要的快速筛选工具，用于选择可以促进特定益生菌作用的菌株。为了研究具有广泛的酶活性和特异性的芽孢杆菌属的种内多样性，从韩国传统发酵食品中分离了190株芽孢杆菌。在初步的安全性筛选中，共发现其中8株卵磷脂酶和溶血活性均为阴性，并选择进行进一步研究。根据不同水平的酶功能（高蛋白水解或低蛋白水解，淀粉分解和脂解（PAL）活性），两个枯草芽孢杆菌选择菌株用于体内研究。将两种品系分别以每天1×10 ⁸ CFU的水平分别给予C57BL / 6小鼠，这些小鼠随意喂食60％高脂饮食8周，而使用抗肥胖药Xenical作为实验设置中的阳性对照。具有低和高淀粉分解活性的枯草芽孢杆菌M34和枯草芽孢杆菌GS40a分别引起显着不同和相反的生理作用。短链脂肪酸的产生似乎与肠道菌群的变化密切相关。