Some lactic acid bacteria (LAB) isolated from beer or wine produce capsular β-glucans from UDP-glucose via the membrane-anchored glycosyltransferase GTF-2. This phenomenon is feared in breweries, because the viscosity of the affected liquids drastically increases due to the β-glucan and concomitant pellicle formation of these LAB. Currently it is unknown if this type of polysaccharide formation provides any advantage for the producing LAB during the colonization of (ethanol-containing) liquids. We thus used the β-glucan producer Levilactobacillus (L.) brevis TMW 1.2112 and its β-glucan-deficient transposon mutant (Δ gtf-2), and compared their growth at different ethanol concentrations and their competitiveness during co-cultivation. No significant inhibition in growth and differences in acidification were observed for both strains up to ethanol concentrations of 8% (v/v). At 10 % ethanol, the β-glucan forming wildtype increased its cell number and produced more acid in comparison to the mutant strain, which settled at the bottom of the fermentation tubes at any tested condition. At higher ethanol concentrations (12–18 % v/v) both strains failed to grow, while a higher viability of the wildtype strain was observed. After co-cultivation of both strains for up to 72 h in liquid nutrient medium (without ethanol), significantly more ropy wildtype colonies were detected, if the wildtype had been initially applied in similar cell counts or in excess. By contrast, the number of smooth mutant colonies was solely significantly higher after 24 h of growth, if the mutant strain had been initially inoculated in excess. These results indicate that the β-glucan-mediated pellicle formation by l. brevis TMW 1.2112 is its dominant phenotype and a selective advantage during colonization of liquids.

从啤酒或葡萄酒中分离出的一些乳酸菌（LAB）通过膜锚定的糖基转移酶GTF-2从UDP葡萄糖中产生荚膜β-葡聚糖。啤酒厂担心这种现象，因为受影响的液体的粘度由于这些LAB的β-葡聚糖和伴随的薄膜形成而急剧增加。目前尚不清楚这种类型的多糖形成是否在定殖（含乙醇）液体期间为生产LAB提供任何优势。因此，我们使用了β-葡聚糖生产者短杆菌Levitactobacillus（L.）短病毒TMW 1.2112及其缺乏β-葡聚糖的转座子突变体（Δgtf-2），并比较了它们在不同乙醇浓度下的生长情况以及共培养期间的竞争力。乙醇浓度不超过8％（v / v）的两种菌株均未观察到明显的生长抑制和酸化差异。与突变株相比，在10％的乙醇中，形成β-葡聚糖的野生型增加了其细胞数量，并产生了更多的酸，该突变株在任何测试条件下均位于发酵管的底部。在较高的乙醇浓度（12–18％v / v）下，两种菌株均无法生长，而野生型菌株则具有较高的生存能力。将两种菌株在液体营养培养基（无乙醇）中共培养长达72小时后，如果最初以相似的细胞计数或过量施用了野生型，则可以检测到明显更多的罂粟野生型菌落。相比之下，如果最初已过量接种突变菌株，则在生长24小时后，平滑突变菌落的数量仅会明显增加。这些结果表明，β-葡聚糖介导的膜形成是通过l。brevis TMW 1.2112是其主要表型，是液体定殖期间的选择性优势。