Institute of Food Science and Biotechnology, University of Hohenheim, Stuttgart, Germany.
Food Microbiol. 2011 May;28(3):583-9. doi: 10.1016/j.fm.2010.11.010. Epub 2010 Nov 26.
The limits for the stability of the microbial association 1 (Lactobacillus sanfranciscensis and Candida humilis) and association 2 (Lactobacillus reuteri, Lactobacillus johnsonii and Issatchenkia orientalis) during sourdough fermentation were evaluated by investigating the effects of the ecological factors substrate, refreshment time, temperature, amount of backslopping and competing species in different combinations on their growth. Sourdoughs were fermented in 28 batches under different conditions using the associations and possible competing strains as starters. The dominating microbiota was characterized by bacteriological culture, rRNA gene sequence analysis and RAPD-PCR. Association 1 was found to be competitive in doughs with rye and wheat flour at temperatures between 20 and 30 °C, refreshment times of 12 and 24 h, amounts of backslopping dough from 5 to 20% and against all competing lactic acid bacteria and yeasts. The processing parameters for the competitiveness of the association 2 were temperatures of 35-40 °C, refreshment times of 12-24 h and the substrates rye bran, wheat and rye flour, but not in every case. Issatchenkia orientalis could only grow when enough oxygen was available. Its cell counts fell rapidly under the limit of detection when using high amounts of doughs (small ratio of surface to volume) and refreshment times of 12 h. In conclusion, the results demonstrated that the two associations were remarkably stable under most of the investigated process conditions.
通过考察生态因素（底物、更新时间、温度、回种量和竞争物种）对微生物共生体 1（旧金山乳杆菌和近平滑念珠菌）和共生体 2（罗伊氏乳杆菌、约氏乳杆菌和东方伊萨酵母）生长的影响，评估了它们在发酵过程中的稳定性极限。使用这些共生体和可能的竞争菌株作为起始菌株，在 28 批不同条件下的发酵中进行了研究。通过细菌培养、rRNA 基因序列分析和 RAPD-PCR 对主导微生物群进行了表征。共生体 1 在 20-30°C 的温度、12 和 24 h 的更新时间、5-20%的回种量的面团中和所有竞争的乳酸菌和酵母存在的情况下，在黑麦和小麦面粉面团中具有竞争力。共生体 2 的竞争力的加工参数为 35-40°C 的温度、12-24 h 的更新时间以及黑麦麸皮、小麦和黑麦面粉等底物，但并非在所有情况下都是如此。东方伊萨酵母只有在有足够氧气的情况下才能生长。当使用大量面团（表面与体积之比小）和 12 h 的更新时间时，其细胞计数在检测限以下迅速下降。总之，结果表明，这两个共生体在大多数研究的工艺条件下具有显著的稳定性。
