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Study seeks new uses for potato waste

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From potatoes to diapers? Researchers at Bemidji State University are working to find new uses for potato waste from processing plants. (Photo by Spencer Platt/Getty Images)
Minnesota is one of the biggest potato producing states in the country. But companies that churn out French fries, Tater Tots and hash browns also produce tons of potato waste each year. Processors have to dispose of that waste somewhere. Sometimes it's thrown onto potato fields to rot. Often, it's sold cheaply to farmers who feed it to cows or pigs.

Environmental scientists at Bemidji State University believe there's a better way. They say fermented potato waste could potentially produce high-value products that are better for the environment.

Bemidji, Minn. — The potato industry generates lots of waste. One-quarter of what goes into a potato processing plant comes out as waste. In Minnesota, that's about 400,000 tons a year.

BSU environmental studies professor Drago Bilanovic enters a small laboratory near the shore of Lake Bemidji. The lab doesn't look like much. But this is where the Bosnian native is doing some cutting edge research on potato waste.

In a corner of the lab, Bilanovic stands over a machine that's slowly spinning about two dozen clear bottles.

"What you see here is a set of bottles in which we have some potato waste and whatnot, and different experimental conditions," said Bilanovic. "So we are trying to figure out how much xanthan we can produce."

Xanthan is something most people haven't heard of. If you're a label reader, you might recognize it as a thickening agent used in salad dressings, yogurt, ice cream and other dairy products.

In its basic form, xanthan is a thin, sticky gel that also has industrial uses. It's used as a stabilizer and thickener in the paint and chemical industry. The oil industry uses it to squeeze more oil from depleted wells.

The global market for xanthan is close to $500 million annually and growing. Xanthan is produced in laboratories by certain types of bacteria. Typically, the base ingredient is sugar. But Bilanovic says that production method is expensive. He says potato scraps can serve the same purpose.

"So what we are trying here is conversion of something of low value, like potato waste, which is, in fact, given away for free," Bilanovic said. "We try to convert it to something that is rather expensive, something that's currently being sold at something like $4 to $6 a pound."

Bilanovic's xanthan project is only part of the potato research going on at Bemidji State. In a parallel study, environmental studies professor Dr. Fu-Hsian Chang is exploring the production of another potential potato waste product called polylactic acid. The substance is relatively new on the market, and isn't being produced in significant quantities. But Chang says its potential impacts are far-reaching.

"I can tell you, the future looks good," said Chang.

Chang says polylactic acid can be used to produce non-petroleum based plastics. He says that's a big deal, since the world's oil supplies are dwindling. He says what's equally important is that plastics made from potato waste would be biodegradable.

"Conventional plastic, after you bury it in a landfill for five decades, six decades and you pull it out, (it's) still the same," said Chang. "Yet this product, we're going to make it biodegradable in just a few months."

Potential markets for polylactic acid include packaging material, things like garbage or sandwich bags, or even coating for time-release capsules in the pharmaceutical industry.

Chang says as the price of oil climbs, alternative polylactic acid-based products will become more attractive and more affordable.

"Our main focus will be for completely biodegradable packaging material," Chang said. "And we're going to make, in the future, the diaper 100 percent biodegradable. So that's probably our best and also the most profitable, the largest volume demand on the market."

Chang is optimistic about the viability of potato waste. Other researchers at BSU are more cautious. Dr. Pat Welle is a professor of economics and environmental studies at Bemidji State. Later this year, Welle plans to do a cost-benefit analysis of mass producing the two materials from potato waste.

Welle says there's no doubt the transition away from a petroleum-based economy will create all sorts of new economic opportunities in agriculture.

We're going to make, in the future, the diaper 100 percent biodegradable ... we can market Minnesota-produced potato waste diaper.
- Dr. Fu-Hsian Chang

"There are all sorts of chemical discoveries being made with these kinds of materials, and starches, sugars and so forth that are being converted," said Welle. "That's just one part of the innovative economy out there, where these kinds of materials are being used in an entirely different way. So it is possible that potatoes, instead of for French fries, could actually be more valuable in some other economic product."

Professor Chang says if the numbers add up after a few years of research, the next step will be to set up a pilot plant that would demonstrate to private industry that potato waste could be profitable.

That would likely have an impact on the potato growing region around Park Rapids. That town is also home to a major potato processor, Lamb-Weston/RDO Frozen. Officials from Lamb-Weston did not return phone calls for this story. But Chang says the company is supplying potato waste for the BSU research, and could be a potential partner down the road.

Professor Drago Bilanovic has seen success in this type of research before. When he was a doctoral student at the Israel Institute of Technology in 1990, Bilanovic became the first to convert citrus waste into xanthan. Bilanovic says he expects similar results from the potato.

"Potato is a great product and can be used as raw material in a number of processes," said Bilanovic. "I don't see any reason why (we shouldn't start) developing industries -- chemical, biochemical industries -- which will be geared toward the utilization of potato and other agricultural products."

Prof. Chang is so confident in the outcome of the potato project that he predicts a full-scale production plant will be in operation within seven years. Chang says he wouldn't be surprised if a biodegradable diaper factory springs up not far from the potato fields of north central Minnesota.

"Everything is going to change," said Chang. "I think this is exciting, and I'm so happy, because I'd like to use my last few years before I retire, hope we can pull out some products. We can market Minnesota produced potato waste diaper."

BSU's Center for Environmental, Earth and Space Studies has been given a $350,000 grant for the potato waste study from the Legislative Commission on Minnesota Resources. The grant will fund the study for two years.

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