Effect of Fermentation Scale and Metabolic Functions for indigo Reduction in the Microbiota under Anaerobic Alkaline Environment

Indigo reduction for solubilization of indigo particle is occurred by the action of the microbiota under anaerobic alkaline conditions in indigo dyeing fermentation. The original microbiota in the raw material (sukumo: composted indigo plant) should be appropriately induced toward extra-cellular electron transfer occurrence microbiota by adjusting environmental factors for the indigo reduction. To understand the induction mechanisms of microbiota and the microbial physiological basis for indigo reduction, microbiota led by different initial redox potential (ORP) causing by the different fermentation scale were analyzed. A rapid ORP decrease occurred in the big batch excluded Actinobacteria effectively and Alkalibacterium, which contributes largely indigo reduction effectively predominated. Functional analyses of microbiota related to indigo reduction indicate that carbohydrate metabolisms, prokaryotic defence system and gene regulatory functions are impotent.