According to a recent article in Science Daily, researchers in China are reporting a discovery that could turn rice straw into an inexpensive, new renewable source of biofuel.
The study is slated to appear in the July 16, 2008 issue of the American Chemical Society's bimonthly journal Energy & Fuels, discussing an innovative way to boost production of biofuel from rice straw by nearly 65 percent.
The researchers point out that China is the world's largest rice producer, a crop which after harvesting, leaves behind approximately 230 million tons of rice straw each year. (Rice straw is the stem and leaves remaining after harvesting the grains.) When taking into account the roughly 431 million metric tons of rice produced around the world this year alone, we're talking about a huge amount of rice straw that could be utilized.
Until now, scientists have not harnessed rice straw for production of biogas because bacteria cannot easily break down its cellulose due to the complex physical and chemical structures of lignocellulosic biomass.
The researchers, however, treated rice straw with sodium hydroxide before allowing bacteria to ferment it into a biogas. That so-called pretreatment increased biogas production by making more cellulose and other compositions in straw available for digestion by the bacteria. So far, three prototype facilities have been built in China using this technology.
In the United States, a new biofuel research plant is being constructed in Yolo County, Calif. The facility is planning on using rice straw, along with other plant materials like wheat straw and grass, to produce biofuel. West Biofuels LLC has invested $2 million for the building costs and research, and hopes to convert agricultural crop waste into 500 gallons of ethanol and other alcohols each day for fuel, chemical feedstocks and electricity generation.
Pan Gen Global, a British corporation with a regional office in Calif., also has plans to open a rice straw processing facility in Stuttgart, Ark. Tom Bowers, the company CEO, explained that the process of making fuel from rice straw "will be similar to corn ethanol. We'll brew (rice waste) just like a beer, extract the sugars and then ferment the sugars."
He also mentioned that Pan Gen Global wants to be producing revenue in the facility by late fourth quarter in 2009. Discussing long-term plans, Bowers stated, "If we can do it in Arkansas successfully-and we honestly believe we can-the technology could be exported to the world. The U.S. produces less than 4 percent of the world's rice product. Take into account China, India, Bangladesh, Indonesia, Central America and South America, and that's a huge area that has the same rice production and waste management problems."