An optimal designed experiment for the alkaline hydrolysis of feather keratin

Abstract

Feathers, burdensome waste from the poultry industry, can be a cheap source of keratin, a protein with excellent physicochemical, biological, and mechanical properties. Acid and alkaline hydrolyses are usually adopted for isolation of keratin from its natural resources. This study aimed at assessing the statistically significant effect of input variables in the alkaline hydrolysis of keratin from chicken feathers on the process yield and on the molecular weight of peptides obtained. The effect of the volume ratio of 1M NaOH to the feathers’ mass, the hydrolysis time, and the shaking speed of the reaction mixture on the process yield were analyzed. The use of statistical analysis at the design step of experiment allowed reducing the trial number from 27 to 9. Among the input variables analyzed, only the volume ratio of 1M NaOH to the feathers’ mass had a significant effect on the process yield, while none of them significantly affected the molecular weight of the peptides obtained. All hydrolysates were dominated by two peptides’ fractions, with molecular weights of ca. 130 and 250 kDa, and mixture of many peptides of weight close to 10 kDa and smaller. Alkaline hydrolysis of feather keratin yielded protein hydrolysates soluble over a wide pH range.

Extraction of Keratin from Chicken Feathers and its Application in the Treatment of Contaminated Water: an Eco-Friendly Approach

“…The process was repeated twice to thrice in order to remove all the unwanted odor, dirt and blood stains from the feathers. After that, feathers were dried in laboratory oven at 40 0 C. After drying, feathers were properly stored and sealed in plastic bags [44].…”

Novel strategy for depolymerization of avermectin fermentation residue to value-added amino acid product

“…As a biosolid, AFR is rich in organic matter, especially proteins, which are as high as 30-50 wt% . Due to the insoluble property, most proteins are difficult to reuse, and the depolymerization process such as acid (Adebiyi et al, 2005;Lopez et al, 2019), alkali (Dabrowska et al, 2022;Solanki et al, 2023), and enzyme hydrolysis (Leni et al, 2020;Pacheco et al, 2023) can be used to release small molecules as nutrient sources (Rezania et al, 2020;Nnaemeka et al, 2021;Chen et al, 2023). Zhang and Zhao.…”

Effect of pre-treatment of chicken feather on the degradation potential of Glutamicibacter arilaitensis

“…The progressive accumulation of chicken feather waste in the environment results in soil pollution, an increase in illnesses, and the emission of nitrous oxide, hydrogen sulphide, and ammonia, which are hazardous to the environment and human health (Li, 2019). The predominant component of chicken feather is keratin, a crosslinked protein that is resistant to physio-chemical, biological and mechanical processes (Dabrowska et al, 2022) and also insoluble in conventional solvents due to the presence of high hydrophobic interactions with densely packed disulfide linkages (Qiu et al, 2022). Feather waste is commonly disposed of by several methods such as incineration, landfilling, and steam pressure cooking, which are expensive and diminish protein quality (Nisi et al, 2020).…”

“…Alkaline hydrolysis causes peptide bonds and disulfide bridges to break down, yet the end product still has all the original amino acids in the protein (Dabrowska et al, 2022). Biodegradation is vital for the environment because it paves the way to reduce feather waste and recycle nutrients to sustain life.…”

“…Some bacterial enzymes have the capacity to disrupt pathogenic fungal cell wall and used as biocontrol agent instead of using commercial pesticides (Narendrakumar et al, 2021). The development of microbiological methods could be an attractive and cheaper method to solubilize feather waste into valuable products (Lateef et al, 2015), and the nature of feather hydrolysate depends upon temperature, pH, and reaction time (Dabrowska et al, 2022). Keratinases are a group of proteases that are active at a wide temperature and pH range and permit the…”