Efficient and Green Isolation of Keratin from Poultry Feathers by Subcritical Water

Abstract

The isolation of keratin from poultry feathers using subcritical water was studied in a batch reactor at temperatures (120–250 °C) and reaction times (5–75 min). The hydrolyzed product was characterized by FTIR and elemental analysis, while the molecular weight of the isolated product was determined by SDS-PAGE electrophoresis. To determine whether disulfide bond cleavage was followed by depolymerization of protein molecules to amino acids, the concentration of 27 amino acids in the hydrolysate was analyzed by GC/MS. The optimal operating parameters for obtaining a high molecular weight protein hydrolysate from poultry feathers were 180 °C and 60 min. The molecular weight of the protein hydrolysate obtained under optimal conditions ranged from 4.5 to 12 kDa, and the content of amino acids in the dried product was low (2.53% w/w). Elemental and FTIR analyses of unprocessed feathers and dried hydrolysate obtained under optimal conditions showed no significant differences in protein content and structure. Obtained hydrolysate is a colloidal solution with a tendency for particle agglomeration. Finally, a positive influence on skin fibroblast viability was observed for the hydrolysate obtained under optimal processing conditions for concentrations below 6.25 mg/mL, which makes the product interesting for various biomedical applications.

Reactive Keratin: Harnessing the Power of Polymer Solutions Extracted Hydrothermally from Poultry Feathers and Wool for Eco-Friendly Functional Finishes on Polyester Textiles

“…In all extracted solutions the protein keratin is expected to be present, which was con rmed with two peaks typical for keratin, i.e., the amide I band at 1600-1700 cm − 1 , which is due mainly to the C = O stretching vibration, and the amide A band at about 3300 cm − 1 , which is due to the hydrogen-bonded NH stretching vibrations [29]. The frequency of this band depends on the strength of the hydrogen bonding [29]. The band at 1546 cm − 1 corresponds to amide II [29].…”

“…Further, A hydrothermal process using subcritical water was applied for the isolation of keratin from waste biomass (cleaned poultry feathers and non-pretreated wool). The process was carried out in a high-pressure, high-temperature batch reactor (4740 series stainless steel, Parr Instruments, Moline, IL, USA) under optimal reaction conditions (temperature 180°C, reaction time of 50 min for wool and 60 min for feathers, material/solvent ratio 1 g/20 mL) determined in our previous studies [29,30]. For each experiment, a speci c amount of wool or feathers (2 g) was placed in a reactor along with water (40 mL).…”

“…On average, 2/3 of the total content were polar components and the smaller part was devoted to the dispersive components. It should be taken into account that keratin and amino acids, which were mainly detected in these solutions [29], are composed of −OH, −COOH and −NH 2 groups, which are polar, and that the solvent is water, which also has a strongly polar character. These results indicate clearly that these solutions have a higher a nity for polar surfaces, but the dispersive moiety is still present, and can contribute to hydrophobic and dispersive interactions when bound to a solid fabric surface.…”

“…The frequency of this band depends on the strength of the hydrogen bonding [29]. The band at 1546 cm − 1 corresponds to amide II [29].…”

A green process for the specific decomposition of chicken feather keratin into polythiol building blocks

“…The autoclaving conditions are close to hydrothermal treatment, which has been described for keratin decomposition. 68–70…”