Okamoto Takahiro, Aino Kenichi, Narihiro Takashi, Matsuyama Hidetoshi, Yumoto Isao
Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukisamu-Higashi, Toyohira-ku, Sapporo, 062-8517, Japan.
School of Biological Science and Engineering, Tokai University, Minamisawa, Minami-ku, Sapporo, 005-8601, Japan.
World J Microbiol Biotechnol. 2017 Apr;33(4):70. doi: 10.1007/s11274-017-2238-1. Epub 2017 Mar 11.
Although the indigo reduction process is performed via natural fermentation and maintained under open-air condition, the indigo-reducing reactions continue for 6 months (on average) or longer. Identifying the mechanism underlying the maintenance of this process could lead to the development of a novel, long-lasting, unsterilized bioprocesses. To determine the mechanisms underlying the maintenance of the indigo fermentation system microbiota for more than 6 months in a reduced state in an anaerobic alkaline environment, we examined changes in the microbiota in one early-phase batch and two aged batches of indigo fermentation fluid. The microbiota in the aged fermentation fluid consisted mainly of the genera Alkalibacterium, Amphibacillus, Anaerobacillus and Polygonibacillus and the family Proteinivoraceae. The genera Alkalibacterium, Amphibacillus and Polygonibacillus are known to include indigo-reducing bacteria. Although the transition speed was slower in the aged fermentation fluid than in the early-stage fluid, the microbiota in the aged fermentation fluid maintained for more than 6 months was drastically changed within a period of 3 months. The results of this study indicate that the bacterial consortia consisted of various indigo-reducing species that replace the previous group of indigo-reducing bacteria. The notable transitional changes may be concomitant with changes in the environmental conditions, such as the nutritional conditions, observed over 3 months. This flexibility may lead to important changes in the microbiota that allow for the maintenance of a fermentation-reducing state over a long period.
尽管靛蓝还原过程是通过自然发酵进行的，并在露天条件下维持，但靛蓝还原反应平均持续6个月或更长时间。确定该过程维持的潜在机制可能会导致开发一种新型的、持久的、无需灭菌的生物过程。为了确定在厌氧碱性环境中靛蓝发酵系统微生物群在还原状态下维持6个月以上的潜在机制，我们研究了一批早期批次和两批老化批次的靛蓝发酵液中微生物群的变化。老化发酵液中的微生物群主要由碱杆菌属、两栖芽孢杆菌属、厌氧芽孢杆菌属、多角芽孢杆菌属以及蛋白食菌科组成。已知碱杆菌属、两栖芽孢杆菌属和多角芽孢杆菌属中包含靛蓝还原菌。尽管老化发酵液中的转变速度比早期发酵液慢，但维持6个月以上的老化发酵液中的微生物群在3个月内发生了巨大变化。本研究结果表明，细菌群落由各种靛蓝还原菌组成，它们取代了先前的一组靛蓝还原菌。这种显著的过渡变化可能与3个月内观察到的环境条件变化（如营养条件）同时发生。这种灵活性可能会导致微生物群发生重要变化，从而使发酵还原状态得以长期维持。
