Lopes Helena de Fátima Silva, Tu Zhihao, Sumi Hisako, Yumoto Isao
Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, Japan.
Laboratory of Environmental Microbiology, Graduate School of Agriculture, Hokkaido University, Sapporo, Japan.
Front Microbiol. 2022 Aug 9;13:957809. doi: 10.3389/fmicb.2022.957809. eCollection 2022.
Water-insoluble indigo is solubilized by the reducing action of microorganisms which occurs during fermentation. In natural indigo fermentation, composted leaves of L. () are the raw material that has been used as both the indigo source and the bacterial inoculum. Ideally, indigo reduction occurs shortly after preparation of the fermentation vat. The time-to-reduction depends on the quality of the and the methods for preparation and management of the fermentation batch. We estimated the effect of adding L. leaf powder (LP) to indigo fermentation in two fermentations originally exhibiting either rapid or slow time-to-reduction (T- and D-, respectively). spp. (97.7%-98.4% similarities with ) were observed only in the LP-added T- fermentation liquor. They appeared from day 1 (0.7%) and increased to 24.4% on day 6, and their presence was related to indigo reduction. Differences in functional ratio between LP-added and its control batches revealed enhancement of pathways related to reconstitution of cellular functions and substrate metabolisms, to all of which spp. contributed intensively. In D- batch, appearance of bacteria necessary to initiate indigo reduction (principally /) was comparatively slower. LP promotes earlier indigo reduction in both T- and D--based batches, owing to its promotion of microbiota transition. The effect of the LP was intensified from day 1 to day 2 in both using batches according to the assumed function of the microbiota. The initial effect of LP on the T- batches was more intense than that in the D- batches and was continued until day 3, while the duration in the T- batches was continued until day 5. Based on these observations, we propose that the LP functions through its phytochemicals that eliminate oxygen, stimulate the microbiota, and accelerate its transitional changes toward a suitable function that opens the pathway for the extracellular electron transfer using carbohydrates as a substrate.
水不溶性靛蓝通过发酵过程中微生物的还原作用而溶解。在天然靛蓝发酵中，堆肥的蓼属植物叶子是用作靛蓝来源和细菌接种物的原料。理想情况下，靛蓝还原在发酵缸制备后不久发生。还原时间取决于蓼属植物的质量以及发酵批次的制备和管理方法。我们在最初表现出快速或缓慢还原时间（分别为T-和D-）的两次发酵中估计了添加蓼属植物叶粉（LP）对靛蓝发酵的影响。仅在添加LP的T-发酵液中观察到与蓼属植物相似度为97.7%-98.4%的物种。它们在第1天出现（0.7%），并在第6天增加到24.4%，它们的存在与靛蓝还原有关。添加LP的批次与其对照批次之间功能比例的差异表明与细胞功能重建和底物代谢相关的途径增强，所有这些蓼属植物物种都有大量贡献。在D-批次中，启动靛蓝还原所需细菌（主要是/）的出现相对较慢。由于LP促进微生物群转变，它在基于T-和D-的批次中都能促进靛蓝更早还原。根据微生物群的假定功能，在两个使用批次中，LP的效果从第1天到第2天增强。LP对T-批次的初始影响比对D-批次更强烈，并持续到第3天，而在T-批次中的持续时间持续到第5天。基于这些观察结果，我们提出LP通过其植物化学物质发挥作用，这些植物化学物质消除氧气、刺激微生物群，并加速其向合适功能的转变，从而为以碳水化合物为底物的细胞外电子转移开辟途径。
