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Biofuels

Productive option

Sorghum is planted to produce ethanol during the sugarcane off-season

On the left, sugarcane plantation during the growth stage. On the side, harvest-ready sorghum with grain panicle. Sorghum is more productive at this stage, unlike sugarcane, which should not flower in order not to lose its culm sugar

MonsantoOn the left, sugarcane plantation during the growth stage. On the side, harvest-ready sorghum with grain panicle. Sorghum is more productive at this stage, unlike sugarcane, which should not flower in order not to lose its culm sugarMonsanto

Consumers are never going to notice that in March and April the ethanol found in some fuel pumps at service stations is not the ethanol traditionally produced from sugarcane. The ethanol will have come from sorghum, a plant of the grass family that sugarcane also belongs to. This situation is predicted by researcher André May, from the Corn and Sorghum Unit of Embrapa (the Brazilian Enterprise for Agricultural Research), who is monitoring various experiments related to introducing sorghum into the country’s energy matrix. Since 2007, Embrapa has been working toward developing sorghum crops during the sugarcane off-season. Embrapa plans to launch three new varieties of this grass this year for the production of ethanol.

Sorghum, unfamiliar to most of Brazil’s urban population, provides farmers with forage for cattle and seeds for poultry and hogs. It provides animals with energy and protein, fulfills their nutritional requirements in a way that closely resembles that of corn. In Africa, where the plant comes from – it probably originated in Ethiopia or Sudan – sorghum is a major food staple, being consumed as sorghum meal.

Sorghum ethanol is expected to fill the gap in the cultivation of sugarcane, which is harvested between April and November. Ethanol shortage in the off-season, from December to March, increases ethanol prices, discouraging the owners of dual fuel cars from buying this fuel. The sorghum growth period is very short – no more than 120 days between planting and harvesting. It can be sown in November or December, February or March, on fallow land allocated for sugarcane – sugarcane fields have to be renovated every five years – or on land allocated for new crops, especially land previously used as pasture. Such circumstances are found in the northeast of São Paulo State, the North of Paraná State , and in Mato Grosso do Sul and Goiás States. Successful experiments with sorghum-derived ethanol are being conducted in Colombia, also during the sugarcane off-season.

Another advantage of sorghum is that the juice extracted from its culm adapts very well to the industrial process of the sugarcane mills where ethanol is normally produced. The changes to the equipment are insignificant, consisting of just a few specific adjustments. The sugarcane harvesters can also harvest sorghum. As a result, the sugar mills can shorten the off-season period, especially between March and April.

062-065_Sorgo_193-1Sorghum has a number of uses, depending on which variety it belongs to. The varieties include forage sorghum, sweet sorghum and grain sorghum. Sweet sorghum has higher sugar content in its culms and can be used to produce sugar, although it is not used for this due to the plant’s lower productivity relative to sugarcane. Embrapa Milho e Sorgo, based in the town of Sete Lagoas in Minas Gerais State, plans to introduce ligno cellulosic sorghum, a strain with a bigger stem, to produce more biomass. This biomass is being prepared for the future production of so-called second generation ethanol, when enzymes will be used to extract the fuel directly from the plant’s bagasse.

“Sorghum will also be used to produce electric power from the burning process in cisterns or to produce steam for heating processes in the food industry processes,” says Robert Schaffert, a researcher at Embrapa Milho e Sorgo. “We expect ligno cellulosic sorghum to produce up to 60 tons of dry matter. This is 2.5 times more than sugarcane or corn.” Schaffert has been studying sorghum for forty years and is a witness to the fact that the idea of using this plant to produce ethanol is not new. “In 1976, the National Alcohol Program (Proálcool) had already considered making ethanol out of sweet sorghum at small distilleries spread throughout the country, because at that time there was no way to transport the ethanol to regions that were far from production centers.”

“We launched three varieties of sweet sorghum which are still available to farmers, even though they have been used as forage or grain throughout this time. In 1985, the focus of the  policy of incentive was changed for the benefit of the big distilleries and we were no longer able to sell this idea to the mills. The solution was to collect genetic material (seeds) and store it in a cold chamber.”

In 2008, Embrapa took up this line of research again, when many sugar mills purchased by big Brazilian conglomerates, such as Petrobras, or by international conglomerates, began to realize that their investments would come to a standstill some months of the year. The mills saw then that sorghum was a possible solution to extend the harvest by 15 or even by 60 days. Lack of activity some months was coupled with a need to produce more ethanol because of the growth of the dual fuel automobile fleet. This caused fuel shortages during the off-season. Embrapa then decided to hire new researchers – including André May and Rafael Parrella – to research sorghum.

062-065_Sorgo_193-2Multinationals such as Monsanto, Ceres and Advanta soon envisioned the possibility of entering the market and began selecting and producing commercial seeds for the new phase of ethanol production. Since November, both Embrapa and these multinationals have planted sorghum in the fields at traditional sugarcane mills. The sorghum will be harvested and processed this month and in April. In 2010, a few hectares were planted experimentally at some sugar mills, with no commercial purpose.

“Between 2002 and 2004 we had identified sweet sorghum during the characterization of Monsanto’s germplasm (genes, seeds) already thinking about the production of ethanol,” says agricultural engineer Urubatan Klink, who heads the commercial sorghum research projects at Monsanto. “Our germplasm is formed through the acquisition of companies in Brazil, the United States, and Mexico. Thus, part of the material that we use to generate hybrid plants is Brazilian and the rest comes from abroad.” Since the mills might be able to produce for an extra two months, the company has been conducting experiments with hybrid seeds since 2009. The experiments consist of cross-breeding traditional (non-transgenic) species with useful characteristics for planting, such as productivity and resistance to diseases.

In 2011, Monsanto launched the first commercial hybrids, following a broad study on the agribusiness of sweet sorghum. “We have tested more than 800 hybrids in the last three years. We expect to test four thousand in the next two years.” This is the opportunity for the company to finally become involved in the production of green energy. In Klink’s opinion, the most important elements in this venture were the participation of researchers and the know-how of Canavialis, a company acquired by Monsanto in 2008. Comprised of researchers specialized in improving sugarcane varieties, the company was created in 2003 after the conclusion of the Sugarcane Genome Project, funded by FAPESP. “That helped us become more knowledgeable about the sugarcane industry,” says Klink.

Ceres, another US based multinational, is specializing in energy producing crops and has also launched two hybrids in 2011. “We’re very optimistic and believe that sorghum will take up 500 thousand hectares in the next three years. We have the information that at least 1.5 million hectares of land will be ready for soil renovation in the next three years,” says agronomy engineer William Burnquist, general manager of Ceres in Brazil. The company hired him away from the Sugarcane Technology Center (CTC) maintained by the sugarcane and ethanol industry, where he had worked for 30 years on sugarcane improvement. He says that the company’s sorghum seeds were planted in November and December at mills owned by the country’s five biggest sugarcane conglomerates in the states of São Paulo and Goiás.

Sorghum is harvested with the same equipment used on sugarcane plantations

MonsantoSorghum is harvested with the same equipment used on sugarcane plantationsMonsanto

“I believe we planted up to 4 thousand hectares. This area could have been bigger had we had more seeds. The demand is enormous,” says Burnquist. Like Monsanto, Ceres has its own fields on which it develops and produces hybrid seeds. The two companies have not released how much they invested in the development and production of sorghum seeds in the country.

Although there is quite a bit of enthusiasm about introducing sorghum to the ethanol industry, and if everything turns out well it will be another outstanding achievement in the success story of biofuel in Brazil, all the stakeholders involved unanimously say that sorghum will not replace sugarcane or invade sugarcane’s space. The productivity-related difference between both plants is still quite substantial. Sugarcane yields 7 thousand liters of ethanol a hectare a year, while sorghum yields 2.5 thousand liters a hectare a year. Nonetheless, given the amount of ethanol yielded by sorghum, the plant will maintain a permanent position at the sugar mills. Planting costs of sorghum are attractive – R$ 2 thousand a hectare, vs. R$ 5 thousand a hectare of sugarcane. In addition, sorghum can be grown and harvested in just four months.

“This year will be decisive for sorghum as a source of ethanol,” says André, from Embrapa. “Sugar mill owners and producers still need to know more about the plant and how to manage it. Sugar mill managers will need to have patience with the workers out in the fields because this crop is in the process of adaption,” he adds. He calculates that sorghum will be planted on approximately 30 thousand acres in the 2011/2012 harvest. There is no official data in this respect. André expects production to expand to 120 thousand hectares. In Brazil, sugarcane plantations cover 8 million hectares.

Uncertainties might arise and possible adjustments might have to be made during the harvests. “Erroneous soil and plantation management could result in yields of 1.5 thousand liters a hectare, which is not profitable,” says André. The plantations must yield at least 2.5 thousand liters a hectare. Sorghum is compatible with the sugar mills’ industrial process, but problems might appear, such as excess starch in the plant’s panicles (where the seeds are found). This can increase the viscosity of the juice during the ethanol production process.

“It is possible to solve these and other problems. For example, we can insert enzymes to reduce the levels of starch,” says Carlos Eduardo Rossell, director of the Industrial Program of the Bioethanol National Science and Technology Laboratory (CTBE) in Campinas, São Paulo State. “This year we are going to keep closer track of the sorghum harvest and prepare a diagnosis of possible problems.” Saccharomyces cerevisiae yeast strains, used to ferment sorghum juice, will also be monitored. Right now, we are using the same yeast strains as the ones used for sugarcane juice,” says agronomy engineer Henrique Amorim, a partner in Fermentec.

This company supplies approximately 80% of the yeasts used by Brazil’s sugarcane mills. “We have been monitoring experiments with sorghum for the last two years. The chemical composition of the juice has variations and we have already identified factors that might affect fermentation. We’re studying new yeasts and will monitor the fermentation process of at least five mills in this sorghum crop,” says Amorim. “Everything is difficult in the beginning, but can all be sorted out with research,” he adds.

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