Sourdough is a common ingredient for baked goods as it improves their texture, shelf life and flavor. One of the dominant key species in type I sourdoughs is Fructilactobacillus sanfranciscensis (formerly Lactobacillus sanfranciscensis), which occurs with a multitude of different strains. Noticeably, this species often shares its habitat with the yeasts Saccharomyces cerevisiae or Kazachstania humilis. It is still unclear, which relationship exists between these organisms and whether it is characterized by coexistence, interaction, or mutualism. In this study, competitiveness of different F. sanfranciscensis strains in rye sourdough was examined and its dependence of co-existing yeasts was explored. In particular, it was investigated whether competitiveness of F. sanfranciscensis strains depends on the presence/absence of S. cerevisiae or K. humilis when co-inoculated in the sourdough. Competitiveness of strains was monitored in rye sourdough using the CRISPR locus length polymorphism (CLLP)—PCR for strain differentiation. It was found that F. sanfranciscensis TMW 1.1150, TMW 1.1221 and TMW 1.1597 were dominant regardless of the presence/absence of both yeast species. Dominance of F. sanfranciscensis TMW 1.392, TMW 1.907 and TMW 1.2137 was significantly and diversely influenced by the presence of S. cerevisiae or K. humilis. F. sanfranciscensis TMW 1.2138 and TMW 1.726 were not able to compete against the other F. sanfranciscensis strains. It was possible to sort the eight strains into three different groups: 1. Strain competitiveness was independent of the presence/absence of yeasts; 2. Strain competitiveness was dependent on yeast species and 3. Strains were not competitive in the presence of strains belonging to group 1 or 2. Interestingly, in fermentations that were not inoculated with any yeast a spontaneous occurrence of S. cerevisiae or K. humilis was observed depending on the synergistic competitiveness of the respective F. sanfranciscensis used. Thus, the level of competitiveness was strain specific and, in some strains, dependent on the presence/absence of specific yeast species.

中文翻译：

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Kazachstania humilis和Saccharomyces cerevisiae在黑麦酸面团中Sanfranciscensis金黄色葡萄球菌菌株的特异性反应中的作用

酸面团是烘焙食品的常用成分，因为它可以改善其质地，保质期和风味。I型酵母中占主导地位的关键物种之一是Sanfranciscensis菌（以前是Sanfranciscensis杆菌），它与多种不同的菌株同时出现。值得注意的是，该物种经常与酿酒酵母或哈萨克斯坦酵母共享其栖息地。尚不清楚这些生物之间存在哪种关系，以及它是否以共存，互动或互惠为特征。在这项研究中，不同F. Sanfranciscensis的竞争力检查了黑麦酵母中的菌株，并探讨了其与酵母共存的依赖性。尤其，研究了竞争力是否F.，旧金山菌株依赖于存在/不存在的S. 酵母或K.蒿草在酵母时共接种。使用CRISPR基因座长度多态性（CLLP）-PCR监测黑麦酵母中菌株的竞争能力，以区分菌株。据发现，F.，旧金山TMW 1.1150，TMW 1.1221和TMW 1.1597占优势无论存在/不存在两个酵母种的。的显性F.，旧金山TMW 1.392，1.907 TMW和TMW 1.2137是显著和多样通过的存在的影响酿酒酵母或K. humilis。F. sanfranciscensis TMW 1.2138和TMW 1.726无法与其他F. sanfranciscensis菌株竞争。可以将这八种菌株分为三个不同的组：1.菌株的竞争力与酵母的存在与否无关；2.菌株竞争力取决于酵母菌种和3.在属于第1组或第2组菌株的菌株中，菌株没有竞争性。有趣的是，在未接种任何酵母的发酵中，自然出现酿酒酵母或沙门氏菌。根据各自的桑弗朗西斯菌的协同竞争力来观察用过的。因此，竞争水平是菌株特异性的，并且在某些菌株中，取决于特定酵母种类的存在/不存在。