Just when you thought it was safe to say "Switchgrass" in casual conversation without being considered a major league energy fanatic, the switch is on. OK, maybe you've never heard of Switchgrass either. Suffice it to say, it is a prairie grass, touted by erudites and endorsed by none other than President George W. Bush during his 2006 Presidential State of the Union Address as a biofuel of the future - able to grow in Texas or Tennessee.
Now, say "Miscanthus!" Mis - can - thus.
Miscanthus, Miscanthus, Miscanthus. Sounds like my substitute teacher we all used to fire spitwads at in fifth grade - Miss Canthus...
Well, it looks like the biofuel gods are at it again, and in my own home state of Illinois, it looks as if the "heavyweight contender" in the world of highly efficient, high-yield biomass solutions is in. The new king, weighing in at up to TWICE the efficiency of the beloved "Switchgrass," is none other than Miscanthus. This, according to Frank Dohleman and colleagues from the Plant Biology Department at the U of I, and reported at this week's annual meeting of the American Society of Plant Biologists.
In an article, reported by Giles Clar, from the Biofuel Review:
Miscanthus more productive than switchgrass as a biofuel feedstock
Posted by Giles Clark, London
Tuesday, 10 July 2007
Results from a study comparing Switchgrass (Panicum virgatum) to Miscanthus (Miscanthus x giganteus) as a biofuel feedstock show that Miscanthus is more than twice as productive as switchgrass. The results were presented this week at the annual meeting of the American Society of Plant Biologists by Frank Dohleman and his colleagues of the Plant Biology Department at the University of Illinois.
Dohleman’s team, which included Dafu Wang, Andrew D.B. Leakey & Stephen P. Long also of University of Illinois, along with Emily A. Heaton of Ceres Inc., theorized that Miscanthus produces more usable biomass than switchgrass because of these three key attributes:
1. Miscanthus can gain greater amounts of photosynthetic carbon per unit of leaf area
2. Miscanthus has a greater leaf area
3. Miscanthus has a longer growing season.
The research team measured the amount of gas exchanged on the upper canopy of Miscanthus leaves from pre-dawn to post-dusk on 20 dates in the 2005 and 2006 growing seasons. The averages from two years’ data showed that Miscanthus gained 33% more carbon than switchgrass. Integrated measurements also showed that the Miscanthus leaf area was 45% greater than switchgrass and that Miscanthus plants grew an average of eleven days longer than switchgrass. This extended growing season and accompanying lower temperatures proved to further boost the photosynthetic activity of Miscanthus. Specifically, pyruvate Pi dikinase was found to be expressed at higher rates when ambient temperatures are lower. This enzyme supports C4 photosynthesis in Miscanthus.
Unraveling the mystery of why Miscanthus is the more productive crop will enable researchers to engineer this and other potential bioenergy crops. These developments will increase production options as well as support efforts within biofuel research and industry to work with non-food based biomass resources.
What is Miscanthus?
Miscanthus is a genus of about 15 species of perennial grasses native to subtropical and tropical regions of Africa and southern Asia, with one species (M. sinensis) extending north into temperate eastern Asia.
Selected species
* Miscanthus floridulus
* Miscanthus giganteus
* Miscanthus sacchariflorus
* Miscanthus sinensis
* Miscanthus tinctorius
* Miscanthus transmorrisonensis
Uses
The sterile hybrid between M. sinensis and M. sacchariflorus, Miscanthus giganteus or "E-grass", has been trialed as a biofuel in Europe since the early 1980s. It can grow to heights of more than 3.5 m in one growth season. Its dry weight annual yield can reach 25t/ha (10t/acre). It is sometimes called "Elephant Grass" and thus confused with the African grass Pennisetum purpureum, also called "Elephant Grass".
The rapid growth, low mineral content and high biomass yield of Miscanthus make it a favorite choice as a biofuel. After harvest, it can be burned to produce heat and power turbines. The resulting CO2 emissions are equal to the amount of CO2 that the plant used up from the atmosphere during its growing phase, and thus the process is greenhouse gas-neutral, if one does not consider any fossil fuels that might have been used in planting, fertilizing, or harvesting the crop, or in transporting the biofuel to the point of use. When mixed in a 50%-50% mixture with coal, it can be used in some current coal-burning power plants without modifications.
M. sinensis is cultivated as an ornamental plant. In Japan, where it is known as susuki(ã™ã™ãÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ), it is considered an iconic plant of late summer and early autumn. It is mentioned in Man'yÅÂÂÂÂÂÂÂÂshÅ«- (Vol8 1538) as one of the seven autumn herbs (akinonanankusa). It is used for the eight month in hanafuda playing cards. It is decorated with Bush clover for the Mid-Autumn Festival. Miscanthus has also excellent fiber properties for papermaking.
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