Institute of Fermentation Technology and Microbiology, Łódź University of Technology, Wolczanska 171/173, 90-024, Łódź, Poland.
Institute of Food Technology and Analysis, Łódź University of Technology, Stefanowskiego 4/10, 90-024 Łódź, Poland.
Microbiol Res. 2020 Nov;240:126540. doi: 10.1016/j.micres.2020.126540. Epub 2020 Jun 27.
Yeasts have a substantial impact on the contamination and loss of food. In this study, we applied bacteria of the genus Lactobacillus as natural biopreservatives. Anticandidal strains of bacteria were selected from among 60 strains of bacteria grown which were each with nine polyols or galactosyl polyols. Polyols and galactosyl polyols can act as prebiotics for lactic acid bacteria and can enhance the antifungal properties of bacteria by affecting their metabolism. The galactosyl polyols significantly improved the anticandidal activity of most of the bacteria we tested. Based on the screening, the most promising strains of bacteria were selected, and their metabolites (both primary and secondary) and enzymatic activity were characterized in the presence of polyols and galactosyl polyols. The qualitative and quantitative content of bacterial metabolites depended both on the bacterial strain and the type of culture medium. A wide variety of antifungals produced by bacteria, such as fatty acids, hydroxy fatty acids, and other acidic products with potential antagonistic activity (phenyllactic acid or hydroxyphenyllactic acid) were detected. The bacteria produced a high concentration of phenyllactic acid in the presence of galactosyl polyols (up to 84.3 mg/L). This finding could suggest that this metabolite may have a significant impact on the antifungal properties of lactobacilli against yeast. Galactosyl polyols influenced the enzymes involved in the synthesis of fatty acids and hydroxylated fatty acids (esterase lipase, acid phosphatase, and α-glucosidase). The mechanism of the antifungal effect of lactobacilli may be based on the synergistic effect of their primary and secondary metabolites, in particular phenyllactic acid.
酵母对食物的污染和损失有重大影响。在本研究中，我们应用乳杆菌属细菌作为天然生物防腐剂。从 60 株生长的细菌中选择抗假丝酵母的细菌菌株，每株细菌使用 9 种多元醇或半乳糖基多元醇。多元醇和半乳糖基多元醇可以作为乳酸菌的益生元，通过影响其代谢来增强细菌的抗真菌特性。半乳糖基多元醇显著提高了我们测试的大多数细菌的抗假丝酵母活性。基于筛选，选择了最有前途的细菌菌株，并在多元醇和半乳糖基多元醇存在的情况下对其代谢物（初级和次级）和酶活性进行了表征。细菌代谢物的定性和定量含量既取决于细菌菌株又取决于培养基的类型。检测到了各种由细菌产生的抗真菌物质，如脂肪酸、羟基脂肪酸和其他具有潜在拮抗活性的酸性产物（苯乳酸或羟基苯乳酸）。在半乳糖基多元醇存在的情况下，细菌产生了高浓度的苯乳酸（高达 84.3mg/L）。这一发现表明，这种代谢物可能对乳酸菌对酵母的抗真菌特性有重大影响。半乳糖基多元醇影响参与脂肪酸和羟基化脂肪酸合成的酶（酯酶脂肪酶、酸性磷酸酶和α-葡萄糖苷酶）。乳酸菌的抗真菌作用机制可能基于其初级和次级代谢物的协同作用，特别是苯乳酸。
