Orange peels may lead to cheap, clean ethanol

By | February 09, 2010
News release posted Feb. 25, 2010

ORLANDO -- Scientists have made a discovery to turn discarded fruit peels and other throwaways into cheap, clean fuel to power the worlds vehicles.

University of Central Florida professor Henry Daniell has developed a way to produce ethanol from waste products such as orange peels and newspapers. His approach is greener and less expensive than the current methods available to run vehicles on cleaner fuel -- and his goal is to relegate gasoline to a secondary fuel.

Daniell's breakthrough can be applied to several non-food products throughout the United States, including sugarcane, switchgrass and straw.

"This could be a turning point where vehicles could use this fuel as the norm for protecting our air and environment for future generations," he said.

Daniell's technique uses plant-derived enzyme cocktails to break down orange peels and other waste materials into sugar, which is then fermented into ethanol.

The most popular source used now is corn starch, which is fermented and converted into ethanol. But ethanol derived from corn produces more greenhouse gas emissions than gasoline does. Ethanol created using Daniell's approach produces much lower greenhouse gas emissions than gasoline or electricity.

There's also an abundance of waste products that could be used without reducing the world's food supply or driving up food prices. In Florida alone, discarded orange peels could create about 200 MMgy of ethanol each year, Daniell said.

More research is needed before Daniell's findings, published this month in Plant Biotechnology Journal, can move from his laboratory to the market. But the other scientists conducting research in biofuels describes the early results as promising.

"Dr. Henry Daniell's team success in producing a combination of several cell wall degrading enzymes in plants using chloroplast transgenesis is a great achievement," said Mariam Sticklen, a professor of crop and soil sciences at Michigan State University. She has researched an enzyme in a cows stomach that could help turn corn plants into fuel.

Daniell's research was funded by the U.S. Department of Agriculture. Depending on the waste product used, a specific combination or "cocktail" of more than 10 enzymes is needed to change the biomass into sugar and eventually ethanol. For example, orange peels need more of the pectinase enzyme, while wood waste requires more of the xylanase enzyme. All of the enzymes Daniell's team uses are found in nature, created by a range of microbial species, including bacteria and fungi.

Daniell's team cloned genes from wood-rotting fungi or bacteria and produced enzymes in tobacco plants. Producing these enzymes in tobacco instead of manufacturing synthetic versions could reduce the cost of production by a thousand times, which means the cost of making ethanol should be significantly reduced, Daniell said.

Tobacco was chosen as an ideal system for enzyme production because of several reasons. It is not a food crop, and an estimated 40 metric tons of biomass -- or "bioenergy" -- are produced annually in each acre of tobacco plants. Enzyme production also would provide an alternate use for this crop and potentially decrease its use for smoking.

Daniell's team includes Dheeraj Verma, Anderson Kanagaraj, Shuangxia Jin, Nameirakpam Singh and Pappachan E. Kolattukudy in the Burnett School of Biomedical Sciences at UCFs College of Medicine. Genes for pectinase enzyme were cloned in Kolattukudy's laboratory.

SOURCE: University of Central Florida News and Information