#872: Dr David Bressler: Destruction of Prions

Intro:  Dr. David Bressler is a Professor in the Faculty of Agricultural, Life and Environmental Sciences at the University of Alberta. 

DR. DAVID BRESSLER

CC:  DAVID, LETS START WITH THE PROBLEM WITH PRIONS.  WHAT IS IT AND HOW BAD IS IT?

DB:  Well most of the public has heard now of “mad cow disease”.  Mad Cow Disease or Bovine Spongiform Encephalopathy if you want the long name, or BSE, is a disease attributed to a prion which is a small protein.  It’s actually a protein that would naturally occur in a mammal, for example, like a cow.

But the protein gets misfolded somehow and they’re not quite sure of the science on how the initiation of that happens.

But basically that misfolded protein acts like a catalyst to misfold other proteins like it.  So two things happen–it takes proteins out of circulation and misfolds them so they start to build up.  At the same time, that triggers the host to make more of that protein so you end up getting a compounding problem.

They are proteins that are naturally occurring in the body, so the body doesn’t necessarily break them down that well.  And eventually you end up with these inclusion bodies or these big clusters of the protein in the brain.  And it ends up making the brain go a little bit, they call it spongiform, which literally means like a sponge or having these big cavities where the proteins are built up.

With that come all kinds of neurological problems and clinical symptoms.

And so the problem was that they’ve discovered or linked scientifically that if a cow gets mad cow disease, it can be linked to other cows.  It’s contagious.  And not only that, if people eat the prions, there is now some ties to the human forms of the disease. 

And so, if you go back in the history of Canada, there have been about 17 cases of mad cow disease, I think is the latest number.  But most of it was a spike back in the last decade.

The reason it became a problem is the prior practice was during rendering, which is the process of taking the part of the cow that doesn’t become meat, for all intents and purposes, and try and recover protein for other uses–protein and oils and fat.

The protein would have some contaminant in it.  So if you processed 100,000 cows and one was infected, you’d infect that batch.

For a time, that protein was used for animal feed inclusion.  So you created a vicious cycle where you were feeding cow parts back to cows, which infected other cows.

So in England, they had a massive problem with BSE.  In Canada, we were already starting to prepare but we did have some of those, those procedures.

So what happened is when we had our first cases of mad cow disease, one of the steps the Canadian Food Inspection Agency took was to ban and outlaw the inclusion of cow parts into animal feed.  So that was a big and important step.

But what it meant was we had to find something to do.

So when you take a cow, historically, and you process it, there was times where half the value of processing the cow came from the co-products.  Not the food.

With BSE what happened is, you eliminated a big chunk of that value, but at the same time, you didn’t sell the steaks for any more.  So you lost half, or not half, but a big chunk of what you could sell the cow for or claim value from.

So what happened is the price of the meat went up in the stores but at the same time, the farmers got paid a lot less for the cow.  And because you had BSE in your repository, it stops the trade internationally.  So for awhile, Japan would not accept Canadian beef.  The US would not accept Canadian beef.  Part of it is a trade issue and part of it is a scientific purpose.

CC:  SO THEN YOU HAVE ALL OF THIS EXCESS MATERIAL.  HOW IS IT BEING DISPOSED OF?

DB:  The stuff that is potentially infected with the prion isn’t the entire cow.  Up until a certain age, they look at the brain and spinal column in some of those materials.  So you’re talking, it depends on who you are talking to, about 20 percent of the cow is considered what we called Specified Risk Material (SRM).

This SRM or Specified Risk Material, the Canadian Food Inspection Agency took a zero risk policy which meant that material could not be exposed to any kind of food chain or the environment.

So CFIA gave approval for four disposal pathways.  The first disposal pathway is probably the harshest which is just incineration.  That’s what was deployed at Cargill with the support of government; they set up incineration facility in southern Alberta.  They were the only one to do that in North America.

The rest of it was option 2, which is landfill.  The problem with landfill is it doesn’t destroy the prion necessarily and that land can never be used again for agricultural production.

Now not to mention in North America, the amount of specified risk material generated is somewhere in the ballpark of 5000 tonnes a week.  So picture landfills with that much protein and rotting, decaying material is not a good environment.

The other two options were thermal hydrolysis which breaking down at high temperature with water or caustic.  So this is adding a strong base and breaking it down at high temperature.

So of those options, the hydrolysis ones had no established value.  You destroy the material, maybe use it as fertilizer for the inorganics.

Incineration, you’re burning sulphur and nitrogen containing materials.  It’s got some energy but it’s not a great feedstock for that.  And landfill isn’t a great sustainable long term solution.

And so, that’s where the Province started working with our lab and others to look at how do we address and create value from this by-product stream.  Clearly we don’t want to go to food with it, but what are our other options?

CC:  SO WHAT HAVE YOU BEEN LOOKING AT IN TERMS OF YOUR RESEARCH?

DB:  For the past now decade, with the support, initially it was the Province and a group called PrionNet, which was a national NCE followed by Alberta Prion Research Institute or APRI, linked now to Alberta Innovates.

We looked at a whole series of how do we use the hydrolysis methods we talked about.  So the first thing we did is we aligned with CFI to get our lab approved to do all this.  It took about a year of shutdown to reformat.

We found ways, after hydrolysis, which is very harsh condition, breaking the protein right down, we started playing chemistry on ways to recombine those little peptides we call them, pieces of protein, back into things like plastic or composites, adhesives, and now flocculating agents.

So one of the things we’re looking at is can we use this material, for example, settling tailing ponds from mine storage or oil sands applications.

So it’s a lot of chemistry, looking at how to modify it for more industrial non-food related use.

CC:  ARE THE PRIONS DESTROYED THOUGH?

DB:  Yes, much of the work before us with CFI showed that hydrolysis would render the material safe.  And in fact, we worked with Dr. Westaway at the Alberta Centre for Prion and Protein Misfolding Diseases to actually look at the material we used, both just after hydrolysis and after chemical recombination just to confirm that it wasn’t infectious.

So we actually did go through a couple years study just confirming that the material was safe and inert.

CC:  SO IF YOU WERE CONVERTING IT TO PLASTICS, WHAT KIND OF PLASTICS?  AND WHAT SORT OF PRODUCTS OR INDUSTRIES WOULD THEY BE USED IN?

DB:  Well although the material is completely safe from a social license and public acceptance, we tried to steer away from food packaging or anything like that.  And we looked at a type of plastic that’s called “thermoset”, which means it’s actually cast permanently.  It’s not a reformable plastic.

And so we were looking at industrial uses, structural materials, some of it was again looking at phenol-formaldehyde replacements in panel boards, in wood products; kind of that terminal safe industrial use is the space we looked at there.

And then some of the other stuff we looked at like the foaming agents or flocculating agents as well, we are looking at it again using it to clean up something like oil spills anticipating these materials are highly biodegradable and so once put in the environment, after we’ve hydrolyzed them, they will be chewed up in the environment.  The initial protein is much more resistant.

CC:  AND YOU ALSO MENTIONED OIL SANDS TAILINGS.  HOW WOULD YOU USE IT THERE?

DB:  Well one of the problems with oil sands tailings ponds is they are not settling at the speed people would like them to.  And reclamation isn’t just about getting the oil settled.  It’s about getting the clay particles to settle to the bottom so the water can be recovered and reused and hopefully the site returned to like a solid ground.

To do that you need to consolidate or push down the solid materials.  And so flocculating agent helps do that.  It kind of binds things together and gets them to fall out of the water column and create kind of solid surface underneath.

And so working with NAIT or the Northern Alberta Institute of Technology, some of the oil sands research centres, we’re looking at trying to adopt and do some chemistry on the proteins to make them good flocculating agents.

CC:  ARE THERE ANY OBSTACLES OR CHALLENGES TO THIS?

DB:  Like everything else in the research world, the obstacles are always, we can do things in the lab.  We get some proof of concept.  There’s an area of optimization where you’ve got to try and get the perfect recipe.  It’s always hard to get funding to do that part of the work.  And then you try to formulate a business case that will seek to investment to do pilot plant and scale up; pretty much like we do with some of the other technologies.  We’re kind of at that stage right now where we’ve filed a bunch of patents on about four different types of applications.  We’ve actually been awarded a national phase in many of these, so we actually hold the space.

The next stage will come at getting investors and moving the corporate development forward.

CC:  IT SOUNDS TO ME THEN YOU SEE THIS HAS A LOT OF PROMISE?

DB:  Well the thing I like about it, is going back to the beginning, if you are land filling this material, it’s a cost.  So instead of the rendering industry selling it for profit, they are now looking at costs estimates are anywhere from $70 to $200 a tonne to get rid of it.

If we can create an industrial use for this material that reclaims value, I’m hoping we can drive value back into the entire whole agricultural chain from producers to processors to renderers.  But to do that we need to find high value applications at the end of the day.

CC:  THANK YOU VERY MUCH.

DB:  You’re welcome.  Thank you for your time today. 

Dr. David Bressler is a Professor in the Faculty of Agricultural, Life and Environmental Sciences at the University of Alberta.