Penn State researchers advance cellulosic biofuels

December 26 2008 / by Garry Golden
Category: Biotechnology   Year: 2019   Rating: 2

Penn State biofuelsPenn State University understands that the future of cleantech and the 'new energy economy' comes down to advancing the fundmantals of chemistry, biology and materials science. 

The University has become a powerhouse for cleantech research and its scientists are pushing the limits of performance around next generation solar cells, fuel cells and cleaner hydrocarbons. 

Now researchers have made a breakthrough related to the breadown of ligin that can be used to lower the cost of cellulosic based biofuels, and change the feedstock industry.

Rethinking the breakdown of Ligin
Lignin is a key piece of cellular walls in woody plant material. Breaking it down to access the energy of chemical bonds in the plant material is one of the great barriers to cost effective cellulosic biofuels. 

"There is lots of energy-rich cellulose locked away in wood," said John Carlson, professor of molecular genetics, Penn State. "But separating this energy from the wood to make ethanol is a costly process requiring high amounts of heat and caustic chemicals. Moreover, fungal enzymes that attack lignin are not yet widely available, still in the development stage, and not very efficient in breaking up lignin."

Bean gene + Poplar Tree + Enzyme
Researchers inserted a gene from beans into a poplar tree that inserts a protein between two lignin molecules when the lignin polymer is created.

"Now we have a lignin polymer with a protein stuck in between," explained Carlson "When that occurs, it creates a type of lignin that is not much different in terms of strength than normal lignin, but we can break open the lignin polymer by using enzymes that attack proteins rather than enzymes that attack lignin."

These enzymes that attack proteins are already used widely in the laundry detergent industry and are commercially readily available, added Carlson.  The genetic modification does not appear to weaken the plants or the crop production.

The easy to breakdown ligin variation may also have major implications for agriculture and livestock industries:

'One of the problems with forage crops such as ryegrass and clover is that they have too much lignin, which can cause ruminants like cows to get sick. Their digestive enzymes go into overdrive to break down the lignin, creating a lot of gas and digestion problems for the animals.'

"All animals produce enzymes in their digestive process that break down amino acids and small proteins that can be absorbed by the intestine," said Carlson. "If this technology were to be transferred to alfalfa or hay or such cattle feed, it might make it easier for the cows to break down the lignin through their own enzymes."

Carlson added that the technology could potentially be transferred to other biomass crops and even help turn agricultural waste products found on farms into animal feed. But the modified plants will require federal approval before they can be commercialized


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