Feather innovation

Poultry feathers can be used to manufacture products ranging from paper to high-quality feed

Published: Sunday 31 December 2000

 Feather fibre: are chicken dy it could be a feather in the cap of us scientists. New research on the byproduct of the poultry industry -- feathers -- is turning the fluff into products ranging from paper to high-quality animal feed. More than 8.5 billion chicken are 'commercially grown' in usa every year, estimates the National Chicken Council, a Washington dc -based poultry group. When processed, these chicken leave behind more than one billion kg of feathers.

Now, Walter Schmidt, a research scientist at the Beltsville, Maryland, branch of the us department of agriculture's agricultural research service ( ars ), has found a new way to process poultry feather into valuable fibres. Feathers are made of keratin, which are tightly-wound tough protein fibres. They are found in hair, wool, fingernails and hooves. Schmidt found that keratin had properties in common with another fibrous material: cellulose, the starch that forms wood and paper.

"The real scientific innovation is that before we did this research, no one seriously thought of feathers as fibre, let alone as a viable and valuable source of fibre," says Schmidt. "Feathers are a great source of fine-diameter, high-surface area, tough, durable fibre -- properties that make fibres in general valuable to many different types of manufacturers," he adds.

Of course, feathers can't be taken from the chicken and made directly into new materials. The stiff central core of the feather, the quill, must be stripped of the flexible, interconnected strands of material that emerge from the barbs. It is only this soft barb material that is useful as feather fibre. Although the whole feather is made of keratin, the crystal structure of the protein in the brittle central quill is different from that in the soft but durable barbs; only the barbs have the desirable properties.

Schmidt and his team have developed an efficient method for sorting quill from barb in chopped feather. Chopped quill and barb parts have a similar weight and density but very different shapes: chopped quills are more globular than the flatter chopped barbs. Turbulent air flow in separating machines move quill parts to the bottom of the device for removal, while barb parts are blown to the top and collected for further use.

The us Environmental Protection Agency ( epa ) estimates that more than 16 billion diapers made of wood pulp are discarded each year. Schmidt estimates a year's worth of feathers could replace approximately 25 per cent of the wood pulp used annually for diapers. The environmental impact could go beyond saving trees: feathers require much less processing than wood pulp, and unlike paper pulp do not require bleaching -- they start out white.

Another scientist has found a way to turn feathers into a better feed product. Jason Shih, a professor of biotechnology and poultry science at North Carolina State University in Raleigh, usa , found -- while developing bioreactor system for converting chicken manure to methane and other byproducts -- stray feathers present in the mix were disappearing. Shih isolated a keratin-digesting strain of the bacterium bacillus lecheniformis . This strain is capable of fermenting feathers, breaking keratin into digestible proteins and amino acids. He has now identified the gene for a keratinase enzyme within the bacterium that actually digests the feathers. Then he improved the yields of the enzyme, making enough of it to use on its own to break feathers down directly rather than using bacteria. Shih's feather-derived animal feed has more than 80 per cent available protein, a substantial improvement over traditional feather meal.

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