Graduate School of Advanced Technology and Science, Tokushima University, 2-1 Minamijosanjima-cho, Tokushima 770-8513, Japan.
Industrial Microbiology, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan.
J Biosci Bioeng. 2021 May;131(5):565-571. doi: 10.1016/j.jbiosc.2021.01.005. Epub 2021 Feb 10.
Cyclic voltammetry was successfully applied to in-vivo monitoring of leuco-indigo in indigo-fermenting suspensions under quiescent conditions without deoxygenation; the working and counter electrodes were kept on the surface of each suspension by a polyethylene vinyl alcohol tube holder. The anodic peak current was used as a measure of the leuco-indigo concentration. The voltammetric wave shape suggested partial solubilization of the indigo with some macromolecules in the fermenting suspensions, which lead to an in-situ method without any electrode surface pretreatment. The anodic peak current well reflected the dyeing activity of a suspensions. The results obtained for laboratory-level fermentation systems clarified the number of days required for dye fermentation, the effectiveness of addition of old suspension as an additive for preparing fresh fermenting suspensions, and the importance of addition of a nitrogen-based nutrient as well as a glucose-based one to recover the indigo-reducing activity. The method can also be applied to determine the amounts of indigo in used dye suspensions and extracts of fermented indigo leaves (sukumo) by adding a chemical reduction pretreatment.
循环伏安法成功地应用于在静止条件下、无需脱氧的情况下对发酵悬浮液中的无色靛蓝进行体内监测；工作电极和对电极通过聚乙烯醇管夹保持在每个悬浮液的表面。阳极峰电流被用作无色靛蓝浓度的度量。伏安波形表明发酵悬浮液中的靛蓝与某些大分子部分溶解，从而形成无需任何电极表面预处理的原位方法。阳极峰电流很好地反映了悬浮液的染色活性。通过对实验室规模发酵系统的研究，明确了染料发酵所需的天数、添加旧悬浮液作为制备新鲜发酵悬浮液添加剂的有效性、以及添加基于氮的营养物和基于葡萄糖的营养物以恢复靛蓝还原活性的重要性。该方法还可以通过添加化学还原预处理来确定用过的染料悬浮液和发酵靛蓝叶（sukumo）提取物中的靛蓝含量。
