目的 筛选具有高效降胆固醇能力的干酪乳酪杆菌，以干酪乳酪杆菌标准菌株为参照研究其降胆固醇能力和益生特性，以期为心血管相关疾病防治和微生物保健品开发提供微生物资源。方法 为获得安全、稳定、高效的降胆固醇益生菌，从老坛子泡菜中筛选获得1株干酪乳酪杆菌S1(Lacticaseibacillus casei S1)，研究了干酪乳酪杆菌S1的益生特性。结果 干酪乳酪杆菌S1较标准菌株D10871的耐酸耐胆盐能力更强，人工胃肠液处理24h后存活率可达37。06％，较D10871高237。80％(t=61。18，P＜0。000 1);对几种有机溶剂的平均疏水性达60。87％，较D10871高39。41％(t=37。64，P＜0。0010);超氧自由基清除率、羟自由基清除率和还原力分别较D10871高222。86％、66。90％和2029。03％;γ-氨基丁酸水平和脂肪酶活性分别较D10871高76。90％、83。90％;S1胆固醇去除率和胆盐水解酶活性分别较D10871高94。15％、213。20％;S1与胆盐共沉淀和菌体同化是其降胆固醇的主要方式，二者占总去除率的82。52％;抗生素敏感试验显示S1的安全性显著优于D10871。结论 干酪乳酪杆菌S1是1株性能稳定、安全可靠的降胆固醇益生菌，具有重要的开发应用潜力。
Screening and characterization of a strain of highly efficient cholesterol-reducing lactic acid bacteria
Objective To screen and identify a high-efficiency cholesterol-lowering probiotic strain that is both safe and stable,so as to provide microbial resources for the prevention and treatment of cardiovascular-related diseases and develop-ment of microbial health products.Methods The strain Lacticaseibacillus casei S1(S1)was screened from pickles made with old-style pottery jar,and its probiotic characteristics was compared with the standard strain D10871.Results Lactic-aseibacillus casei S1 exhibited stronger acid and bile salt tolerance.Specifically,after 24 hours in artificial gastrointestinal fluid,the survival rate of S1 was 37.06％,which was 237.80％higher than that of D10871(t=61.18,P＜0.000 1).S1 also demonstrated higher hydrophobicity,with an average hydrophobicity in several organic solvents being 60.87％,which was 39.41％higher than that of D10871(t=37.64,P＜0.001 0).S1 also showed higher antioxidant activity,with the superoxide radical scavenging rate,hydroxyl radical scavenging rate and reducing capability being 222.86％,66.90％and 2 029.03％higher than those of D10871,respectively.S1 also had a higher gamma-aminobutyric acid content and lipase activity than D10871,by 76.90％and 83.90％,respectively.Most importantly,S1 showed a significantly higher cholesterol removal rate and bile salt hydrolase activity,primarily via co-precipitation with bile salt and bacterial assimilation.Specifically,the cho-lesterol removal rate and bile salt hydrolase activity of S1 were 68.75％and 6.17 U/mL,which were 94.15％and 213.20％higher than those of D1 0871,respectively.Additionally,S1 was found to be safer than D1 0871 based on antibiotic sensitiv-ity tests.Conclusion Lacticaseibacillus casei S1 is a promising,safe and reliable probiotic strain for lowering cholester-ol level,with great potential for further development and application.
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