Nishita Masatoshi, Hirota Kikue, Matsuyama Hidetoshi, Yumoto Isao
School of Biological Science and Engineering, Tokai University, Minamisawa, Minami-ku, Sapporo, 005-8601, Japan.
Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukisamu-Higashi, Toyohira-ku, Sapporo, 062-8517, Japan.
World J Microbiol Biotechnol. 2017 Jul;33(7):133. doi: 10.1007/s11274-017-2300-z. Epub 2017 Jun 5.
Indigo-reducing bacteria perform natural fermentation in indigo fermentation fluid. Owing to the stochastic nature of the process, the constituent in indigo fermentation fluid differ depending on the prepared batch and fermentation period. To identify new indigo-reducing bacteria, isolation of the bacteria is indispensable. However, isolation of indigo-reducing bacteria is difficult because conventional media are often unsuitable to isolate these slow-growing bacteria that also exist in low numbers. Hydrolysates of polysaccharides and mixtures of plant base constituents are candidates to accelerate the isolation of indigo-reducing bacteria that cannot be isolated using conventional media. In this current study, wheat bran hydrolysate and composted indigo leaves (sukumo) were used as ingredients in the fermentation fluid in the selective medium for indigo-reducing bacteria in anaerobic culture. The results suggested that obligate and oxygen-non-metabolizing facultative anaerobes are difficult to isolate using conventional media, whereas oxygen-metabolizing facultative anaerobes, relatively rapid-growing and major bacterial strains are relatively easy to isolate. Media containing sukumo hydrolysate facilitated the isolation of novel species of Bacillus pseudofirmus-related strains, whereas media containing wheat bran hydrolysate facilitated the isolation of Amphibacillus spp. (including new species). Seven species (including two new species) of indigo-reducing bacteria were isolated using wheat bran hydrolysate-containing media, whereas six species (including three new species) of indigo-reducing bacteria were isolated using media containing both wheat bran and sukumo hydrolysates. These newly developed culture media will facilitate the isolation of unknown bacteria in indigo fermentation and in environments similar to indigo fermentation fluid.
靛蓝还原菌在靛蓝发酵液中进行自然发酵。由于该过程的随机性，靛蓝发酵液中的成分会因制备批次和发酵周期的不同而有所差异。为了鉴定新的靛蓝还原菌，分离这些细菌是必不可少的。然而，靛蓝还原菌的分离很困难，因为传统培养基通常不适用于分离这些生长缓慢且数量稀少的细菌。多糖水解产物和植物基成分的混合物有望加速分离那些无法用传统培养基分离的靛蓝还原菌。在本研究中，麦麸水解产物和堆肥靛蓝叶（sukumo）被用作厌氧培养中靛蓝还原菌选择性培养基发酵液的成分。结果表明，专性厌氧菌和非氧代谢兼性厌氧菌很难用传统培养基分离，而氧代谢兼性厌氧菌，即相对快速生长的主要细菌菌株则相对容易分离。含有sukumo水解产物的培养基有助于分离新型类假芽孢杆菌相关菌株，而含有麦麸水解产物的培养基有助于分离两栖芽孢杆菌属（包括新物种）。使用含麦麸水解产物的培养基分离出了7种（包括2个新物种）靛蓝还原菌，而使用同时含有麦麸和sukumo水解产物的培养基分离出了6种（包括3个新物种）靛蓝还原菌。这些新开发的培养基将有助于在靛蓝发酵以及与靛蓝发酵液类似的环境中分离未知细菌。
