The present disclosure relates to the biosynthesis of indigoid dye precursors and their conversion to indigoid dyes. Specifically, the present disclosure relates to methods of using polypeptides to produce indigoid dye precursors from indole feed compounds, and the use of the indigoid dye precursors to produce indigoid dyes.

A dyeing method includes immersing a fiber into a dye for dyeing the fiber, in which the dye includes indigo and indirubin, and the indigo and the indirubin have a weight ratio of 20:1 to 80:1. The indigo in the dye has a concentration of 0.1% o.w.f. to 5% o.w.f. The dyed fiber may simultaneously have high luminance, high color saturation, high strength of colorization, and sufficient colorfastness.

A dyeing method includes immersing a fiber into a dye for dyeing the fiber, in which the dye includes indigo and indirubin, and the indigo and the indirubin have a weight ratio of 20:1 to 80:1. The indigo in the dye has a concentration of 0.1% o.w.f. to 5% o.w.f. The dyed fiber may simultaneously have high luminance, high color saturation, high strength of colorization, and sufficient colorfastness.

The present disclosure relates to the biosynthesis of indigoid dye precursors and their conversion to indigoid dyes. Specifically, the present disclosure relates to methods of using polypeptides to produce indigoid dye precursors from indole feed compounds, and the use of the indigoid dye precursors to produce indigoid dyes.

The present disclosure relates to the biosynthesis of indigoid dye precursors and their conversion to indigoid dyes. Specifically, the present disclosure relates to methods of using polypeptides to produce indigoid dye precursors from indole feed compounds, and the use of the indigoid dye precursors to produce indigoid dyes.

Systems and methods are described whereby a deoxygenated liquid dye material is made by supplying the deoxygenated inert gas to a liquid dye material that is susceptible to oxidation, and mixing the liquid dye material in the presence of the supplied deoxygenated inert gas with water and at least one dye formulation component selected from the group consisting of reducing agents, pH adjusters, foaming agents, wetting agents and auxiliary chemicals to form a deoxygenated aqueous dye composition having an oxygen content of 30 ppm oxygen or less. A supply of inert gas may be provided which is then passed to a gas purifier to reduce oxygen content in the inert gas to, e.g., 1 ppb oxygen or less. The deoxygenated aqueous dye composition that is formed may have an oxygen content of 1 ppm or less.

Aqueous leucoindigo solution comprising an aromatic amine, in particular aniline or aniline and N-methylaniline, wherein the concentration of the aromatic amine is below 200 ppm, wherein the leucoindigo salt in the solution is in the form of a mixed sodium and potassium salt, wherein the molar ratio of sodium to potassium is in the range of from above 3:1 to 10:1, preferably wherein the concentration of the salt is in the range of from above 25 to 45% by weight, based on the total weight of the solution.

Aqueous leucoindigo solution comprising an aromatic amine, in particular aniline or aniline and N-methylaniline, wherein the concentration of the aromatic amine is below 200 ppm, wherein the leucoindigo salt in the solution is in the form of a mixed sodium and potassium salt, wherein the molar ratio of sodium to potassium is in the range of from above 3:1 to 10:1, preferably wherein the concentration of the salt is in the range of from above 25 to 45% by weight, based on the total weight of the solution.

Stable aqueous leucoindigo solution comprising an aromatic amine in the form of aniline or aniline and N-methylaniline, wherein said leucoindigo is in the form of an alkali metal salt; wherein the concentration of the aromatic amine is below 40 ppm determined according to ISO 14362-1:2017(E); and wherein the concentration of the leucoindigo salt is in a concentration range of from 10 to 45% by weight based on the total weight of the solution, and wherein the stability of the solution is measured at a temperature of 23° C.; or wherein the concentration of the leucoindigo salt is in a concentration range of from 45 to 65% by weight based on the total weight of the solution, and wherein the stability of the solution is measured at a temperature of 60° C.

Stable aqueous leucoindigo solution comprising an aromatic amine in the form of aniline or aniline and N-methylaniline, wherein said leucoindigo is in the form of an alkali metal salt; wherein the concentration of the aromatic amine is below 40 ppm determined according to ISO 14362-1:2017(E); and wherein the concentration of the leucoindigo salt is in a concentration range of from 10 to 45% by weight based on the total weight of the solution, and wherein the stability of the solution is measured at a temperature of 23° C.; or wherein the concentration of the leucoindigo salt is in a concentration range of from 45 to 65% by weight based on the total weight of the solution, and wherein the stability of the solution is measured at a temperature of 60° C.