They look a bit like brown poker chips on steroids, but the chocolate-colored discs created by University of Alberta researcher Dr. David
Bressler and his lab actually represent an unlikely new source for bio-plastics.
Using the discarded parts of beef carcasses that were removed from the value-added production process after bovine spongiform encephalopathy (BSE) rocked the sector in 2003, Bressler, an associate professor in the U of A’s Department of Agricultural, Food and Nutritional Science, is collaborating with industry, government and other researchers to forge cattle proteins into heavy-duty plastics that might soon be used in everything from auto components to CD cases. The project began when beef by-products such as blood and bone were regulated out of the rendering process after BSE was found in Canada, for fear the material contained deadly prions – infectious proteins that cause BSE (better known as mad cow disease). “Because of the new regulations, parts of the cow that could previously be eaten were now being treated as a hazardous material,” Bressler said. “And because the industry doesn’t always have the resources necessary to build production lines to segregate this material, it winds up throwing out far more than is necessary.” And even then, the waste doesn’t end. “Any landfill that receives the protein can never again be used for agricultural production, because the prions are very resistant to the environment,” Bressler added.
How do Bressler and his team – which includes Phillip Choi, a professor in the U of A’s Faculty of Engineering; and John Wolodko, a senior researcher at Alberta Innovates Technology Futures – synthesize the material from bovine by-product into bio-plastic? Hold onto your lunch. “Through thermal and caustic hydrolysis, which uses high temperature water to break down the proteins, we take chunks of protein filled with bone and hair and transform them into something that looks like molasses,” Bressler explained. “We then extract and crosslink the protein molecules to create a polymer network that forms a rigid structure.”
The new plastics from Bressler’s lab are currently being tested by Mississauga, Ont.-based auto parts maker The Woodbridge Group. “When developing a new material, it’s better to work with an end-user and design the performance criteria to meet what they need,” Bressler explained. “We’re at the point now where we’ve had various cross-linkers that are working well, and we’re getting more of a rigid structural-type plastic.” Current funding is focused on research to investigate whether the plastics can be mixed with renewable fibres such as hemp. If successful, the resulting bio-composite could be used in high-strength applications like building structural elements. (But don’t expect to see the beef protein-based bio-plastics turning up in certain applications anytime soon. “The material is completely safe, but because of potentially negative consumer perceptions, we’re going to stay away from any food-packaging or medical applications,” Bressler said.)
The project – which is supported by the Alberta Prion Research Institute, PrioNet Canada and the Alberta Livestock and Meat Agency – is still in the development stage, and much work remains to be done. “It took us a year just to characterize what we had after the hydrolysis,” Bressler said. “Over the next year we’re looking to refine recipes in different crosslinkers; we then expect to spend a few more years doing certification and testing before the material is ready for commercial applications.”
But in the end, Bressler insists that crafting bio-plastics from beef protein waste is a win-win-win prospect. “It sounds bizarre at first, but, as in any other chemistry process, we’re simply breaking material down into small building blocks and resynthesizing it,” he said. “The plastics industry is under pressure to increase the renewable content in its products, and this project offers them the opportunity to do just that, and at the same time help send value back to rural Alberta and the beef sector.”
Source : www.canplastics.com