Today, sorghum-to-ethanol production uses the grain, like corn, but the plants themselves hold the greatest potential for biofuel production. New thermochemical and biochemical conversion technologies are making it possible to utilize the entire plant, including its carbohydrates that comprise plant cell walls, namely cellulose.
Sorghum is a genus comprising many different tropical grass species. All of them take the so-called C4 pathway to fix carbon dioxide through photosynthesis to make carbohydrates, a far more efficient strategy than that of C3 plants. Sweet sorghum and grain sorghums are cultivated most widely, with the latter used as fodder in the West, and as food in many developing countries (map shows suitable regions for sorghum, click to enlarge). Several species have received a great deal of research attention lately because they are seen as near-ideal crops for cellulosic biofuels and biogas (earlier post). So far, scientists have succeeded in designing more robust, drought-tolerant varieties (here), cultivars with a low lignin content (earlier post), hybrids with high sugar content for ethanol (more here), high-biomass yielding varieties (earlier post), and even sorghums resistant to aluminum toxicity - an achievement of major importance for the developing world (more here).
Sorghum produces high yields, is naturally drought tolerant and can thrive in places that do not support corn and other food crops. Sorghum also fits into established production systems and is harvested the year it is planted, unlike perennial grasses, so it fits well in a crop mix with perennial species and existing crops, like cotton. - Dr. Bill Rooney, Plant scientist of the A&M System's Texas Agricultural Experiment Station (TAES)As next-generation bioconversion technologies mature, farmers will transition from growing as much grain per hectare to producing as much biomass as they can per hectare, with as little energy and agronomic inputs as possible. This means new crops and specialized hybrids like high-biomass sorghum types will be needed.
A pioneer in developing high-biomass sorghum, Dr. Bill Rooney's first breeding lines - the precursors to hybrids - can approach 20 feet (6 meters) under favorable conditions, and could produce more than 2,000 gallons of ethanol per acre (18,800 liters per hectare) - more than four times the current starch-to-ethanol process:
energy :: sustainability :: bioenergy :: biofuels :: ethanol :: cellulose :: bioconversion :: biomass :: soghum ::
To accelerate product development, Ceres and TAES will work together to expand their marker-assisted breeding efforts. Markers allow plant breeders to identify useful traits in seed tissue or when plants are still seedlings. Large numbers of markers provide a roadmap of the sorghum genome, cutting years off development timelines for new products, and making it easier to improve the makeup of the plants to facilitate processing. Markers and biotechnology will be crucial for developing sorghum for cellulosic biofuels.
Peter Mascia, Ceres Vice President of Product Development, said Ceres has Texas-sized expectations for the collaboration. "When we combine their resources with our high-throughput trait development capabilities, we believe we can double the rate of improvement to biomass yields, while expanding the range of the crop for earlier planting in cooler and drier conditions, especially on so-called marginal or unproductive land," he says. Mascia expects that commercial quantities of the initial hybrids will be available in time to meet the requirements of the first cellulosic biorefineries currently being planned.
As part of this agreement, Ceres will obtain exclusive commercialization rights to TAES's high biomass sorghum hybrids developed in the joint research program. The TAES program will receive royalties as well as financial and technology support from Ceres. Other aspects of the collaboration were not disclosed.
Ceres, Inc. is leading developer of high-yielding energy crops that can be planted as feedstocks for cellulosic ethanol production. Its development efforts cover switchgrass, sorghum, miscanthus, energycane and woody crops. Founded as a plant genomics company, Ceres holds one of the world's largest proprietary collections of fully sequenced plant genes. Recently, the company raised $75 million to develop dedicated energy crops (earlier post).
The Texas Agricultural Experiment Station operates upon the foundation that "Agriculture is Life." TAES is a science and technology agency under The Texas A&M University System charged with conducting basic and applied research in agriculture, the life sciences and natural resources. The agency's mission is to generate scientific knowledge that benefits both consumers and the agriculture industry in Texas and beyond.
Picture credit: Dr. William Rooney.
Texas A&M University: Bioenergy Initiative: Designing Sorghum for the U.S. Biofuels Industry [*.pdf], Department of Soil & Crop Sciences
William L. Rooney, Designing Sorghum as a Dedicated Bioenergy Crop, Department of Soil & Crop Sciences, Texas A&M University.
Biopact: Scientists release new low-lignin sorghums: ideal for biofuel and feed - September 10, 2007
Biopact: Sun Grant Initiative funds 17 bioenergy research projects - August 20, 2007
Biopact: Major breakthrough: researchers engineer sorghum that beats aluminum toxicity - August 27, 2007
Biopact: U.S. scientists develop drought tolerant sorghum for biofuels - May 21, 2007
Biopact: Sweet super sorghum - yield data for the ICRISAT hybrid - February 21, 2007
Biopact: Mapping sorghum's genome to create robust biomass crops - June 24, 2007
Biopact: Germans research sorghum varieties for biogas production - April 12, 2007