Plants with Altered Lignin Structure May Yield more Biofuel

Genetically modified plants expressing ‘wood-breaking’ enzymes or those with altered lignin content could be the key to a cheaper and greener way of making ethanol, according to researchers from the Pennsylvania State University. The approach also could help turn agricultural waste into food for livestock.

There are lots of energy-rich cellulose in wood, but they are woven in with lignin, a biopolymer that provides plants with strength and protection against pathogens and pests. Separating lignin from cellulose can be time consuming and very expensive, requiring high amounts of hot acids. Genetically modified plants with reduced lignin content have already been developed by researchers. But these plants are usually limp, unable to stay upright, and susceptible to herbivore and microbial attacks.

Instead of decreasing the lignin content of plants, scientists at the Pennsylvania State University altered the structure of the biopolymer. They took a gene from parsley and introduced it into a poplar tree. The gene encodes a protein that inserts itself between two lignin molecules when the lignin polymer is created. The altered lignin is not much different in terms of strength than normal lignin. But they can easily be degraded, using enzymes that attack proteins rather than enzymes that attack lignin. The discovery may also lead to forage crops that can easily be digested by ruminants.

Read the complete article at http://live.psu.edu/story/36682