Food, Drug & Natural Products Health Research Center, Golestan University of Medical Science, Gorgan, Iran.
Department of Food Science and Technology, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.
Probiotics Antimicrob Proteins. 2021 Apr;13(2):343-355. doi: 10.1007/s12602-020-09697-w.
The use of probiotic, postbiotic, and anti-aflatoxigenic capabilities of the lactic acid bacteria (LAB) isolated from stressful niches is a major strategy to prepare functional cultures and bio-preservatives for food industries. In the present study, abundant LAB strains isolated from natural honey were screened based on their tolerance to continuous pH and bile salt treatments. Then, the pro-functional properties of the selected LAB were investigated. In accordance with the screening data, a bacilli isolate was selected for further characterization. Sequencing results led to the identification of Lactobacillus kunkeei as the selected LAB isolate. In vitro antibacterial and antifungal activities of the LAB and in situ antifungal activity of the isolate cell-free supernatant (CFS) were verified against food-borne indicators. Accordingly, in vitro antibacterial and antifungal effects of Lact. kunkeei ENH01 on respective Escherichia coli and Aspergillus niger were significantly (P < 0.05) higher than the other indicators. Furthermore, in situ inhibitory effect of Lact. kunkeei CFS on Candida albicans (as the highest in situ effect) was equal to 76.36%. The presence of three antibacterial peptides was also verified in the Lact. kunkeei CFS according to the results of liquid chromatography mass spectrometry (LC/MS) assay. Antibiotic susceptibility profile and auto-aggregation ability of the isolate were noticeable. Anti-mycotoxigenic capabilities of Lact. kunkeei ENH01 as viable and heat-killed cells were also revealed against total aflatoxins according to the HPLC-based analysis. In vivo safety of the isolate was also attested through the evaluation of blood biochemistry and hematological parameters in the Lact. kunkeei ENH01 fed-mice compared with the control. Based on the findings, probiotic properties of Lact. kunkeei ENH01 and postbiotic capabilities of the isolate CFS and its heat-killed cells were approved.
从应激小生境中分离出的益生菌、后生元和抗黄曲霉的乳酸菌（LAB）的使用是为食品工业制备功能性培养物和生物防腐剂的主要策略。在本研究中，根据其对连续 pH 值和胆汁盐处理的耐受性，从天然蜂蜜中筛选出大量的 LAB 菌株。然后，研究了所选 LAB 的功能特性。根据筛选数据，选择了一株杆菌进行进一步鉴定。测序结果表明，所选的 LAB 是一株 kunkeei 乳杆菌。LAB 的体外抗菌和抗真菌活性以及分离株无细胞上清液（CFS）的原位抗真菌活性均针对食源性病原体进行了验证。因此，Lact. kunkeei ENH01 在体外对相应的大肠杆菌和黑曲霉的抗菌和抗真菌作用明显（P < 0.05）高于其他指示物。此外，Lact. kunkeei CFS 对白色念珠菌的原位抑制作用（最高的原位效应）相当于 76.36%。根据液相色谱-质谱（LC/MS）分析的结果，还在 Lact. kunkeei CFS 中验证了三种抗菌肽的存在。该分离株的抗生素敏感性谱和自动聚集能力也很明显。根据基于 HPLC 的分析，Lact. kunkeei ENH01 作为活菌和热灭活细胞对总黄曲霉毒素的抗真菌能力也得到了证实。通过与对照相比，在 Lact. kunkeei ENH01 喂养的小鼠中评估血液生化和血液学参数，也证明了该分离株的体内安全性。基于这些发现，批准了 Lact. kunkeei ENH01 的益生菌特性以及分离株 CFS 和其热灭活细胞的后生元特性。
