The mechanism of bacterial indigo reduction

Abstract

The reduction of water-insoluble indigo by the recently isolated moderate thermophile, Clostridium isatidis, has been studied with the aim of developing a sustainable technology for industrial indigo reduction. The ability to reduce indigo was not shared with C. aurantibutyricum, C. celatum and C. papyrosolvens, but C. papyrosolvens could reduce indigo carmine (5,5'-indigosulfonic acid), a soluble indigo derivative. The supernatant from cultures of C. isatidis, but not from cultures of the other bacteria tested, decreased indigo particle size to one-tenth diameter. Addition of madder powder, anthraquinone-2,6-disulfonic acid, and humic acid all stimulated indigo reduction by C. isatidis. Redox potentials of cultures of C. isatidis were about 100 mV more negative than those of C. aurantibutyricum, C. celatum and C. papyrosolvens, and reached -600 mV versus the SCE in the presence of indigo, but potentials were not consistently affected by the addition of the quinone compounds, which probably act by modifying the surface of the bacteria or indigo particles. It is concluded that C. isatidis can reduce indigo because (1) it produces an extracellular factor that decreases indigo particle size, and (2) it generates a sufficiently reducing potential.

Decolorization and biodegradation of Indigo carmine by a textile soil isolate Paenibacillus larvae

“…Biodegradation of indigo dyes was carried out by a variety of microorganisms including alkalophilic bacteria, (Nakajima et al 2005), thermophilic bacteria, (Nicholson et al 2005), anaerobic bacteria, (Nicholson et al 2004). Enzymatic degradation of Indigo carmine with laccases from the fungi Trametes hisuta and Sclerotium rolfsia was reported (Campos et al 2001).…”

Electrochemical and sonoelectrochemical monitoring of indigo reduction by glucose

“…1). Anthraquinones have been recognized to stimulate indigo reduction by pure cultures of bacteria [17,18], and anthraquinone-rich madder powder was an invariable ingredient in the medieval indigo dye vat [19]. Here, we show a strong catalytic effect for the 1,8-dihydroxyanthraquinone redox mediator and that the presence of the redox mediator allows the indigo reduction process to be conducted with a lower alkali concentration.…”

Dyeing Properties and Storage Stability of Leaf Powder Prepared from Dyer's Knotweed (I) - by Freeze Drying method -

“…, 박테리아 환원(발효) 14,15) , 환원당을 이용한 환원 16,17) , 전기화 학적 환원 18,19) , 가수분해 효소(β-glucosidase)를 이 용하여 인디고 전구체에서 인독실을 얻는 방법 …”