Nav: Home

Potato waste processing may be the road to enhanced food waste conversion

August 17, 2017

With more than two dozen companies in Pennsylvania manufacturing potato chips, it is no wonder that researchers in Penn State's College of Agricultural Sciences have developed a novel approach to more efficiently convert potato waste into ethanol. This process may lead to reduced production costs for biofuel in the future and add extra value for chip makers.

Using potato mash made from the peelings and potato residuals from a Pennsylvania food-processor, researchers triggered simultaneous saccharification -- the process of breaking down the complex carbohydrate starch into simple sugars -- and fermentation -- the process in which sugars are converted to ethanol by yeasts or other microorganisms in bioreactors.

The simultaneous nature of the process was innovative, according to researcher Ali Demirci, professor of agricultural and biological engineering. The addition to the bioreactor of mold and yeast -- Aspergillus niger and Saccharomyces cerevisiae, respectively -- catalyzed the conversion of potato waste to bioethanol.

The bioreactor had plastic composite supports to encourage and enhance biofilm formation and to increase the microbial population.

Biofilms are a natural way of immobilizing microbial cells on a solid support material. In a biofilm environment, microbial cells are abundant and more resistant to environmental stress causing higher productivities. In this application, these benefits were especially important because mold enzyme activity required higher temperature and the yeast had to tolerate this.

Researchers evaluated the effects of temperature, pH and aeration rates in biofilm reactors, and the optimal conditions were found to be 95 degrees Fahrenheit and a pH of 5.8 with no aeration. After 72 hours, the researchers achieved the maximum ethanol concentration of 37.93 grams per liter. The yield was 0.41 grams or ethanol per gram of starch.

"These results are promising, because the co-culture biofilm reactor provided similar ethanol production -- 37.93 grams per leader -- compared to the conventional ethanol production -- 37.05 grams per liter -- which required pre-treatment with added commercial enzymes at a higher temperature," Demirci explained. "Therefore, eliminating the externally added enzyme and energy costs will certainly reduce the cost of bioethanol production."

Researchers also evaluated biofilm formation of co-culture on the plastic composite supports using a scanning electron microscope, said researcher Gulten Izmirlioglu, a doctoral student in agricultural and biological engineering when the study was conducted. "Scanning electron microscope images revealed that when mold and yeast are allowed to form a biofilm, hyphae (filaments) of the mold provide surface area for the yeasts' attachment," she said. "That's a good thing."

The research findings, which demonstrated that plastic composite supports can be used for simultaneous saccharification and fermentation processes in biofilm reactors with co-cultures when producing ethanol, were published in Fuel. Izmirlioglu believes the results are significant for industry.

"Overall, bioethanol production from starchy industrial wastes can be improved with application of biofilm reactors, while the production cost is reduced with integrations of the simultaneous saccharification and fermentation process and co-culturing," she said.

More efficient bioethanol production is needed to meet the demand for renewable energy and reduce the negative environmental impacts of petroleum fuel, Demirci noted. To make ethanol production cost-competitive, inexpensive, and easily available, feedstocks such as potato mash are needed, as well as improved processing technologies with higher productivities.

"This research is of great interest to Keystone Potato Products in Hegins, Pennsylvania, a subsidiary of Sterman Masser Inc.," said Demirci. "The company is paying attention to this project, hoping this novel approach may help it add more value to its waste potato mash. Industrial food wastes are potentially a great substrate in production of value-added products to reduce the cost, while managing the waste economically and environmentally."

Also contributing to the research was John Cantolina in the Microscopy and Cytometry Facility at the Huck Institutes of the Life Sciences, Penn State.
-end-
The Turkish Ministry of Education, by providing a scholarship to Izmirlioglu and the Pennsylvania Agricultural Experiment Station supported this work.

Penn State

Related Ethanol Articles:

Ethanol fuels large-scale expansion of Brazil's farming land
A University of Queensland-led study has revealed that future demand for ethanol biofuel could potentially expand sugarcane farming land in Brazil by 5 million hectares by 2030.
Measuring ethanol's deadly twin
ETH Zurich researchers have developed an inexpensive, handheld measuring device that can distinguish between methanol and potable alcohol.
Modified enzyme can increase second-generation ethanol production
Using a protein produced by a fungus that lives in the Amazon, Brazilian researchers developed a molecule capable of increasing glucose release from biomass for fermentation.
Scientists develop a chemocatalytic approach for one-pot reaction of cellulosic ethanol
Scientists at the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences have developed a chemocatalytic approach to convert cellulose into ethanol in a one-pot process by using a multifunctional Mo/Pt/WOx catalyst.
New core-shell catalyst for ethanol fuel cells
Scientists at Brookhaven Lab and the University of Arkansas have developed a highly efficient catalyst for extracting electrical energy from ethanol, an easy-to-store liquid fuel that can be generated from renewable resources.
Yeast makes ethanol to prevent metabolic overload
Why do some yeast cells produce ethanol? Scientists have wondered about this apparent waste of resources for decades.
Corncob ethanol may help cut China's greenhouse gas emissions
A new Biofuels, Bioproducts and Biorefining study has found that using ethanol from corncobs for energy production may help reduce greenhouse gas emissions in China, if used instead of starch-based ethanol.
'Dancing' holes in droplets submerged in water-ethanol mixtures
Researchers from Tokyo Metropolitan University have observed the formation of holes that move by themselves in droplets of ionic liquids (IL) sitting inside water-ethanol mixtures.
Tiny particles increase in air with ethanol-to-gasoline switch
The concentration of ultrafine particles less than 50 nanometers in diameter rose by one-third in the air of São Paulo, Brazil, when higher ethanol prices induced drivers to switch from ethanol to gasoline, according to a new study by a Northwestern University chemist, a National University of Singapore economist and two University of São Paulo physicists.
Cutting the cost of ethanol, other biofuels and gasoline
Biofuels like the ethanol in US gasoline could get cheaper thanks to experts at Rutgers University-New Brunswick and Michigan State University.
More Ethanol News and Ethanol Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Rethinking Anger
Anger is universal and complex: it can be quiet, festering, justified, vengeful, and destructive. This hour, TED speakers explore the many sides of anger, why we need it, and who's allowed to feel it. Guests include psychologists Ryan Martin and Russell Kolts, writer Soraya Chemaly, former talk radio host Lisa Fritsch, and business professor Dan Moshavi.
Now Playing: Science for the People

#538 Nobels and Astrophysics
This week we start with this year's physics Nobel Prize awarded to Jim Peebles, Michel Mayor, and Didier Queloz and finish with a discussion of the Nobel Prizes as a way to award and highlight important science. Are they still relevant? When science breakthroughs are built on the backs of hundreds -- and sometimes thousands -- of people's hard work, how do you pick just three to highlight? Join host Rachelle Saunders and astrophysicist, author, and science communicator Ethan Siegel for their chat about astrophysics and Nobel Prizes.