There is an effort world wide to find microbes to breakdown cellulosic and lignin based vegetable matter for producing fuels. Ashli Brown, Ph.D., at Mississippi State University and her students are working at the gut microbes used to breakdown bamboo.
Unlikely as it may sound, giant pandas Ya Ya and Le Le in the Memphis Zoo are making contributions toward shifting production of biofuels away from corn and other food crops and toward corncobs, stalks and other non-food plant material.
Last week Brown and her team presented an update on efforts to mine Ya Ya and Le Le’s ‘assets’ for substances that could do so during the 246th National Meeting & Exposition of the American Chemical Society. If things work out the giant pandas Er Shun and Da Mao in the Toronto Zoo will be joining the quest by making their own contributions.
Brown explains, “The giant pandas are contributing their feces. We have discovered microbes in panda feces might actually be a solution to the search for sustainable new sources of energy. It’s amazing that here we have an endangered species that’s almost gone from the planet, yet there’s still so much we have yet to learn from it. That underscores the importance of saving endangered and threatened animals.”
The Mississippi State team has identified more than 40 microbes living in the guts of giant pandas at the Memphis Zoo that could make biofuel production from plant waste easier and cheaper. That research, Brown added, also may provide important new information for keeping giant pandas healthy.
Bacteria in giant panda digestive tracts are prime candidates for breaking down lignocellulose. Not only do pandas digest a diet of bamboo, but have a short digestive tract that requires bacteria with unusually potent enzymes for working down the lignocellulose. “The time from eating to defecation is comparatively short in the panda, so their microbes have to be very efficient to get nutritional value out of the bamboo,” Brown said. “And efficiency is key when it comes to biofuel production — that’s why we focused on the microbes in the giant panda.”
Ethanol made from corn is the most common alternative fuel in the U.S. However, there are ill-founded concerns that wide use of corn, soybeans and other food crops for fuel production may raise food prices or lead to shortages of food.
Brown points out that corn stalks, corncobs and other plant material not used for food production could be better sources of ethanol. Currently that requires special processing to break down the tough lignocellulose material in plant waste and other crops, such as switchgrass, grown specifically for ethanol production. Breaking down this material is costly and requires a pretreatment step using heat and high pressure or acids. Brown and other scientists are looking for bacteria that are highly efficient in breaking down lignocellulose and freeing up the material that can be fermented into ethanol.
Working with scientists at the University of Wisconsin-Madison, Brown’s team identified bacteria that break down lignocellulose into simple sugars, which can be fermented into bioethanol. They also found bacteria that can take those sugars and transform them into oils and fats for biodiesel production. Brown said that either the bacteria themselves or the enzymes in them that actually do the work could be part of the industrial process.
“These studies also help us learn more about this endangered animal’s digestive system and the microbes that live in it, which is important because most of the diseases pandas get affect their guts,” said Brown. “Understanding the relationships between the microbes and the pandas, as well as how they get their energy and nutrition, is extremely important from a conservation standpoint, as fewer than 2,500 giant pandas are left in the wild and only 200 are in captivity.”
Further plans include expanding the work to include samples from the red pandas at the Memphis Zoo, which also eat bamboo. Brown and her colleagues also are forging a collaboration to get samples of feces from giant pandas that arrived in the Toronto Zoo earlier in 2013.
Lots of ideas have come and gone in the lignocellulosic breakdown hunt. While their remains a lot of corn stalk talk, there couldn’t be a lot of use without serious ecological harm to the world’s prime soils. But the lignocellulosic source materials are a vast store of carbon ready for ingenuity to create the fuels of the future. Someday the process breakthrough will come – that’s when the shift to biofuels will finally be a player in setting consumer prices for transport fuels.