Megur Ashwinipriyadarshini, Daliri Eric Banan-Mwine, Balnionytė Toma, Stankevičiūtė Jonita, Lastauskienė Eglė, Burokas Aurelijus
Department of Biological Models, Institute of Biochemistry, Life Sciences Center, Vilnius University, Vilnius, Lithuania.
Department of Molecular Microbiology and Biotechnology, Institute of Biochemistry, Life Sciences Center, Vilnius University, Vilnius, Lithuania.
Front Microbiol. 2023 Sep 8;14:1213370. doi: 10.3389/fmicb.2023.1213370. eCollection 2023.
The present work aimed to identify probiotic candidates from Lithuanian homemade fermented food samples. A total of 23 lactic acid bacteria were isolated from different fermented food samples. Among these, only 12 showed resistance to low pH, tolerance to pepsin, bile salts, and pancreatin. The 12 strains also exhibited antimicrobial activity against ATCC 29213, ATCC 14028, ATCC 12384, ATCC 19615, and ATCC 13883. Cell-free supernatants of isolate 3A and 55w showed the strongest antioxidant activity of 26.37 μg/mL and 26.06 μg/mL, respectively. Isolate 11w exhibited the strongest auto-aggregation ability of 79.96% as well as the strongest adhesion to HCT116 colon cells (25.671 ± 0.43%). The selected strains were tested for their synbiotic relation in the presence of a prebiotic. The selected candidates showed high proliferation in the presence of 4% as compared to 2% galactooligosaccharides. Among the strains tested for tryptophan production ability, isolate 11w produced the highest L-tryptophan levels of 16.63 ± 2.25 μm, exhibiting psychobiotic ability in the presence of a prebiotic. The safety of these strains was studied by ascertaining their antibiotic susceptibility, mucin degradation, gelatin hydrolysis, and hemolytic activity. In all, isolates 40C and 11w demonstrated the most desirable probiotic potentials and were identified by 16S RNA and later confirmed by whole genome sequencing as 11w, and 40C: following with the harboring plasmid investigation. Out of all the 23 selected strains, only 11w showed the potential and desirable probiotic properties.
本研究旨在从立陶宛自制发酵食品样本中筛选益生菌候选菌株。共从不同发酵食品样本中分离出23株乳酸菌。其中，只有12株对低pH具有抗性，对胃蛋白酶、胆盐和胰酶具有耐受性。这12株菌株还对ATCC 29213、ATCC 14028、ATCC 12384、ATCC 19615和ATCC 13883表现出抗菌活性。分离株3A和55w的无细胞上清液表现出最强的抗氧化活性，分别为26.37μg/mL和26.06μg/mL。分离株11w表现出最强的自聚集能力，为79.96%，对HCT116结肠细胞的黏附能力也最强（25.671±0.43%）。在益生元存在的情况下，对所选菌株的合生元关系进行了测试。与2%的低聚半乳糖相比，所选候选菌株在4%的低聚半乳糖存在下具有更高的增殖能力。在测试色氨酸产生能力的菌株中，分离株11w产生的L-色氨酸水平最高，为16.63±2.25μm，在益生元存在的情况下表现出精神益生菌的能力。通过确定这些菌株的抗生素敏感性、黏蛋白降解、明胶水解和溶血活性来研究其安全性。总体而言，分离株40C和11w表现出最理想的益生菌潜力，并通过16S RNA鉴定，随后通过全基因组测序确认为11w和40C，接着进行了携带质粒的研究。在所有23株所选菌株中，只有11w表现出潜在的和理想的益生菌特性。
