Chickens could be the unexpected beneficiaries of the
growing biofuels industry, feeding on proteins retrieved from the
fermenters used to brew bioethanol, thanks to research supported by the
Engineering and Physical Sciences Research Council (EPSRC).
It has long been known that the yeasty broth left over after
bioethanol production is nutritious, but it has taken a collaboration
between Nottingham Trent University and AB Agri, the agricultural
division of Associated British Foods, to prove that Yeast Protein
Concentrate (YPC) can be separated from the fibrous cereal matter.
The researchers have also shown that YPC may be a cost-competitive
substitute for imported soya-based and similar high-value protein feeds
currently used in the diets of chickens bred for meat production.
The project was born out of the vision of biofuels pioneer Dr Pete
Williams of AB Agri, who was convinced valuable material was being
overlooked when cereals were fermented to make bioethanol.
With Dr Emily Burton of Nottingham Trent University, he was able to
secure funding from the EPSRC for a CASE* studentship that allowed them
to develop and analyse the process.
To establish the nutritional value of the concentrate, EPSRC CASE
student Dawn Scholey examined the composition of the newly isolated,
patented YPC in a series of experiments, which showed that it can be
readily digested by chickens. A paper outlining this research is
published in this month's issue of the journal Food and Energy Security.
Project supervisor, Dr Burton says the work is only just beginning:
"Bioethanol is already a 60-billion-litre per year global market but
this project shows the fuel itself is only half the story -- immense
value lies within other co-product streams too. As well as the proteins,
the yeast content provides important vitamins and other
micronutrients."
Produced by distilling and fermenting wheat and other agricultural
feedstocks, bioethanol has particular potential for use as a petrol
substitute. Currently, the dried distiller's grains with solubles (DDGS)
generated as a co-product are sold to the cattle-feed market but this
is not big enough to absorb all material that would be generated if
bioethanol production ramps up significantly in future.
Dr Burton believes the project helps address an issue often raised in
connection with cereal-based biofuels: "One concern with bioethanol is
the perception it will compete with food crops for limited farmland. Our
new work shows how the two can live side by side."
The new, patented process separates DDGS into three fractions --
fibre, a watery syrup and YPC, allowing global production of almost 3
million tonnes of supplementary high-quality protein per annum alongside
current levels of bioethanol produced. A project at a US bioethanol
facility is now up and running, demonstrating the performance of the
process at factory scale.
Every year, 800 million chickens are reared for meat production in
the UK and 48 billion worldwide. As well as helping to feed these birds,
YPC could partially replace the fish meal used on commercial fish
farms.
Dr Pete Williams of AB Agri, the industrial sponsor of the work,
says: "We couldn't have got this development started without the EPSRC
CASE studentship that allowed us to establish the proof of concept, and
to confirm the value-creation potential of our innovative separation
process. By helping us to move to the next key stage of development, it
has brought closer the prospect of full-scale industrial use that could
deliver major benefits to the emerging 'green' fuel sector."
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