Transformation of raw feather waste into digestible peptides and amino acids

Abstract

BACKGROUND: Millions of tons of feather waste from the poultry industry are disposed of annually despite containing a high level of keratin. The aim of this study was to compare the hydrolysis of non-treated feather waste using three different approaches (whole cell microbial digestion, enzymatic and chemical cleavage) and to test the use of hydrolysates as peptone substitutes in a culture medium. RESULTS: Among bacterial isolates, Pseudomonas sp. P5 exhibited the highest keratinolytic activity and efficiency to hydrolyse raw feather material. The hydrolysates contained up to 301 mg L −1 of free amino acids and 6.2 g L −1 of peptides. Hydrolysates obtained by digestion using semi-purified keratinase from Pseudomonas sp. P5 were richer in amino acids (1191 mg L −1 , 56% essential ones) but peptides were present in lower amounts (up to 3.3 g L −1 ). The third approach was feather treatment under mild alkaline conditions. This provided the highest amount of peptides (17.2 g L −1 ) but a significantly lower level of amino acids, especially the essential ones. CONCLUSIONS: All approaches tested could convert raw feather waste into products of commercial value with proven use in a cultivation medium. The level of peptides, their molecular size and amino acid composition was dependent on the method used.

Use of wheat straw and chicken feather hydrolysates as a complete medium for lactic acid production

“…The hydrolysate was supplemented with all MRS nutrients except for yeast extract, peptone and beef extract. The composition of the hydrolysate was analysed as described previously (Stiborova et al 2016).…”

“…Therefore, inexpensive alternatives to these components are preferred as medium supplements. Annually, about 5 million tons of chicken feathers are generated by the poultry industry (Gao et al 2014), and this is used for the production of animal feed supplements such as feather meal (Taskin et al 2012) or disposed of in landfills (Stiborova et al 2016). Since 90-92% of feather is composed of keratin, a protein rich in cysteine, arginine, threonine and hydrophobic amino acids, it can have nutrient potential providing its structure can be effectively broken down.…”

Chicken feather hydrolysate as an inexpensive complex nitrogen source for PHA production byCupriavidus necatoron waste frying oils

“…Nevertheless, classical methods of feather disposal, such as incineration or landfilling, have already been restricted or banned in some countries due to the pollution they create (Stiborova et al . ). Thus, there is an inevitable need for new technologies that enable ecologically and economically sensible processing of this waste.…”

Waste products from the poultry industry: a source of high‐value dietary supplements

“…The different types of waste material produced in poultry industry can be valorized. For example, manure can be used for biogas production; the feathers can be hydrolyzed to obtain a product rich in peptides and amino acids or the poultry litter, including meat and bones, can be incinerated at high temperatures (600–900 °C) to obtain a biochar which is rich in phosphorus and calcium . One of these waste materials from the poultry industry results from the mechanical separation of meat (MSM) which is defined in Regulation 853/2004/EC (Annex I, points 1.14 and 1.15).…”

“…However, this increased production creates an enormous amount of waste products such as feathers, viscera, head, blood, and feet as the slaughter yields are about 70-80%. [3][4][5][6][7] The conversion of these wastes into products with added value is an important biotechnological tool for making the poultry industry more efficient and profitable.…”