Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukisamu-Higashi, Toyohira-ku, Sapporo, 062-8517, Japan.
Laboratory of Environmental Microbiology, Graduate School of Agriculture, Hokkaido University, Kita-ku, Sapporo, 060-8589, Japan.
World J Microbiol Biotechnol. 2019 Jul 26;35(8):123. doi: 10.1007/s11274-019-2699-5.
Constituents of the seed microbiota and initial changes in the microbiota in fermentations are important in fermentation progression. To identify the origin of indigo-reducing bacteria and understand the initial changes in the microbiota that occur concomitantly with the initiation of indigo reduction during indigo fermentation, we analysed the initial changes in the microbiota. The proportions of the reported indigo-reducing taxa Alkalibacterium, Amphibacillus and Polygonibacillus increased to 24.0% on the 5th day, to 15.2% on the 7th day and to 42.8% at 4.5 months, and the relative abundances of these taxa were 0.048%, 0.14% and 0.02%, respectively, in sukumo (composted Japanese indigo plant material used for fermentation). In the early phase of the microbiota transition, two substantial changes were observed. The first change may be attributed to the substantial environmental changes caused by the introduction of heated wood ash extract (pH ≥ 10.5, temperature ≥ 60 °C). This change increased the proportions of Alkalibacterium and the family Bacillaceae. The second change in microbiota might be initiated by the consumption of oxygen by aerobic microorganisms until the 5th day followed by an increase in the abundance of the obligate anaerobe Anaerobranca and the aerotolerant Amphibacillus and a decrease in the abundance of Bacillaceae. This experiment demonstrated that the 0.048% Alkalibacterium in the original material was augmented to 23.6% of the microbiological community within 5 days. This means that using the appropriate material and performing appropriate pretreatment and adjustment of fermentation conditions are important to increase the abundance of the taxa that reduce indigo.
种子微生物群的组成和发酵过程中微生物群的初始变化对发酵进程很重要。为了确定还原靛蓝细菌的来源并了解在靛蓝发酵过程中伴随靛蓝还原起始而同时发生的微生物群的初始变化，我们分析了微生物群的初始变化。第 5 天，报告的还原靛蓝分类群 Alkalibacterium、Amphibacillus 和 Polygonibacillus 的比例增加到 24.0%，第 7 天增加到 15.2%，第 4.5 个月增加到 42.8%，这些分类群的相对丰度分别为 0.048%、0.14%和 0.02%，在 sukumo（用于发酵的经过堆肥的日本靛蓝植物材料）中。在微生物群过渡的早期阶段，观察到两个重大变化。第一个变化可能归因于引入加热的木灰提取物（pH≥10.5，温度≥60°C）引起的环境剧烈变化。这种变化增加了 Alkalibacterium 和 Bacillaceae 家族的比例。微生物群的第二个变化可能是由好氧微生物消耗氧气引起的，直到第 5 天，随后需氧的 Anaerobranca 和兼性耐氧的 Amphibacillus 的丰度增加，而 Bacillaceae 的丰度减少。该实验表明，原始材料中 0.048%的 Alkalibacterium 在 5 天内增加到微生物群落的 23.6%。这意味着使用合适的材料并进行适当的预处理和发酵条件调整对于增加还原靛蓝的分类群的丰度很重要。
