Researchers at the Penn State University revealed that genetically modifying plants could be what we need for a more environmental-friendly and cheaper way of producing ethanol. This could also help convert agricultural waste into livestock food.
At the center of the scientific study is lignin, an important element of woody plant material. This protective barrier is woven in with cellulose, making plants strong and sturdy enough to withstand microbial attack and strong gusts of wind. However, this "plastic wall" makes access to the cellulose much harder.
According to John Carlson, molecular genetics professor at Penn State, "There is lots of energy-rich cellulose locked away in wood. But separating this energy from the wood to make ethanol is a costly process requiring high amounts of heat and caustic chemicals." He adds that enzymes of fungi that attack lignin are still in the development stage and not yet widely available. They are also not efficient in breaking up the protective barrier.
Genetically engineering lignin
Scientists have attempted to address the problem by decreasing the lignin content. This procedure, however, can lead to several problems. One of the major problems is that plants may become limp and unable to stay upright and become more susceptible to pest attacks. According to Ming Tien, biochemistry professor at Penn State, "Trying to engineer trees without lignin is like trying to engineer boneless chicken. It just doesn’t make sense."
Penn State biochemists and geneticists use a different approach in modifying lignin. Instead of decreasing the lignin content, Tien, Carlson, and postdoctoral associate Haiying Liang attempted to engineer lignin connections, without compromising either the plant’s structural rigidity or the lignin’s biosynthesis.
The researchers took a bean gene and modified it into a poplar tree. It yielded a protein that injected itself between two lignin molecules upon the creation of the the lignin polymer. Carlson explains, "Now we have a lignin polymer with a protein stuck in between." The team has already filed a provisional patent on their approach.
The results look promising. The team found that genetically modifying lignin created a type of lignin, which does not weaken the plant. "We can break open the lignin polymer by using enzymes that attack proteins rather than enzymes that attack lignin," Carlson says. Also, the genetic modification may have turned lignin more efficient and greener sources of ethanol. This could also aid in transforming agricultural waste into livestock food.