Green process to regenerate keratin from feathers with an aqueous deep eutectic solvent

Abstract

In the present study, waste feathers were processed into uniform keratin feedstock using an aqueous, inexpensive and non-toxic deep eutectic solvent.

Ductile keratin films from deep eutectic solvent-fractionated feathers

“…These spectra are typical for keratin, 20 and similar spectra were obtained for DES fractionated feather keratin also earlier. 12 Like 1 H-NMR indicated, no major changes in the keratin structure can be observed when keratin was used to prepare lms or cross-linked. In all the lm samples, new bands at 1098, 1042, and 995 cm À1 are due to glycerol in the lms.…”

“…1 shows the experimental set-up for the DES fractionation and the lm preparation. The DES fractionation was carried out as previously described 12 with minor modications. In this Fig.…”

“…In this study, feathers were fractionated using an aqueous DES composing of NaOAc and urea to obtain keratin powder to prepare the dispersions for lm casting. This DES has been earlier used to process feathers 12 but, in this study, the treatment was used on the larger scale for the rst time, and two utilisable keratin fractions were successfully obtained. The rst fraction was obtained by precipitation of keratin by adding water aer the dissolution.…”

“…11 In addition to NMMO and ILs, a rather new type of solvents, deep eutectic solvents (DESs), have been used to dissolve feathers. 12 DESs have similar properties with ILs and they are also easy to prepare with low preparation costs and toxicity. 13 Aqueous solutions based on urea and 2-mercaptoethanol (2 ME), [14][15][16][17] sodium metabisulte (Na 2 S 2 O 5 ), 18 and cysteine 8 as well as sodium sulphide (Na 2 S), [19][20][21] have been used to solubilise feather keratin to prepare lms.…”

A sustainable solvent based on lactic acid and l-cysteine for the regeneration of keratin from waste wool

“…4 Developing a green and efficient method for the isolation of keratin from keratin-rich waste biomass has become a research hotspot which can simultaneously mitigate the environmental issues of waste streams. 5,6 Keratin is a fibrous protein rich in cysteine content (11-17 wt%). 2,7 Cysteine is a hydrophobic aliphatic amino acid containing a thiol functional group (-SH) ionizable at physiological pH ( pH ∼ 7.00) with the ability to form a disulfide bridge (Cys-S-S-Cys) in its oxidized form.…”