pH-Controlled bio-reduction of indigo with S. cerevisiae whole-cell biotransformation

Abstract

Indigo is one of the most widely used dyes in history, but its application is currently greatly limited due to the lack of clean and efficient reduction methods. Aimed at the long-term consumption of traditional bio-reduction of indigo and the ecological problems existing in the application of chemical reducing agents, a high-efficiency indigo dyeing method based on pH-controlled bio-reduction of Saccharomyces cerevisiae under an aerobic environment at normal temperature was constructed. The results showed that the reduction ability of the bio-reduction system and its effect on dye reduction was closely related to the growth and metabolism of cells and the pH of the system. It is worth noting that a suitable alkaline environment is a key to improving the reduction capacity and shortening the reduction time. Under the dyeing pH condition of 10, the K/S of the fabric could reach 6.2 and exhibited the greatest color strength with good fastness after dyeing for 4 days. A pH-controlled bio-reduction strategy with whole-cell biotransformation was designed to construct an indigo green dyeing system with high efficiency and less environmental pollution.

Insights into the dyeing using natural indigo (Indigofera tinctoria): Toward an environmentally friendly garment

“…The use of bio‐sugars instead of sodium dithionite (Na 2 S 2 O 4 ) as reducing agents makes the dying process more eco‐friendly. However, it still has some drawbacks and efficiency improvements are required for a wider commercial application 36 . The beginning of indigo dye reduction is recognised by the formation of a carbon‐coloured layer on the solution surface.…”

“…However, it still has some drawbacks and efficiency improvements are required for a wider commercial application. 36 The beginning of indigo dye reduction is recognised by the formation of a carbon-coloured layer on the solution surface. Then, the solution colour turns from blue to yellow or brownish green.…”