After almost five centuries of being used only to produce sugar and a few minor products, such as brandy, alcohol and molasses, sugarcane in Brazil became the source of an infinite number of derivatives and the subject of numerous scientific and technological research projects.
Ethanol (obtained from the fermentation of sugars) has grown as another main product in the last three decades, dividing with sugar the sucrose extracted in the mills. But now it is the waste products, such as bagasse, straw and vinasse, that are gaining prominence.
Vinasse, the effluent from ethanol distillation, will feed the microscopic algae that will produce biodiesel in a few years, according to a project of the Agricultural Sciences Center (CCA) of the Federal University of São Carlos, in Araras, located 170 kilometers from São Paulo.
Its many nutrients will accelerate the proliferation of algae that are rich in fatty acids to produce biofuels
In addition, fertilizers will be produced, since “the algae sequester up to 64 percent of the potassium present in the vinasse,” Octavio Valsechi, head of CCA’s Agroindustrial Technology Department, told IPS.
Another advantage is that it avoids the monoculture of oilseeds on extensive lands. The question is whether its cost will not be higher than that of biodiesel made from vegetable oils.
Bagasse is increasingly being used to generate electricity in the sugar mills themselves. But a biomass gasification center, to be built in the next three years in Piracicaba, 160 kilometers from São Paulo, offers more promising prospects.
Coal is already being gasified in the world, but biomass technology will only now be tested on an industrial scale
The increasing mechanization of the harvest, which will cover the entire crop in the state of São Paulo, where 60 percent of the national production takes place, as of 2014, means that the sugarcane straw will no longer be burned. But the best way to collect it in the field is still being studied.
“You can get out of sugarcane everything that oil produces,” Tadeu Andrade, director of the Sugarcane Technology Center (CTC), told IPS.
Its vinasse, rich in potassium, fertilizes its replanting as well as the residues left in the industry’s filters and the straw left on the soil, he said, although he later acknowledged that it is necessary to supplement it with chemical fertilizers.
The sugarcane broth, before becoming sugar or ethanol, is a substrate for multiplying microorganisms that serve a number of products, from polymers that regenerate bones, food, medicines and various cosmetics, and even blood plasma, said Valsechi, lamenting the shortage of researchers for the enormous demand for sugarcane.
The road to hydrogen energy could also lie in sugarcane, he said. Alcohol chemistry” is already well advanced in Brazil, and a large petrochemical company produces plastics called “green”, because they are biodegradable.
The sugarcane can also be used to make a type of aviation fuel. Empresa Brasileira de Aeronáutica, a major manufacturer of small and medium-sized passenger and military airplanes, announced a test flight in 2012 with a biokerosene-powered aircraft.
This diversification of sugarcane products, promoting scientific knowledge of their potential, originated in the National Alcohol Program (Proalcohol), launched in 1975 to substitute gasoline and reduce oil imports, the price of which had quadrupled in 1973.
Since then, the Brazilian sugarcane harvest has increased sevenfold, mitigating oil pressure, but generating other problems that require solutions. Vinasse, for example, was an environmental disaster at the beginning of Proalcohol. Spilled in rivers, it killed millions of fish in the 1980s by depriving them of oxygen.
Ethanol production from sugarcane is still being prevented in many Latin American countries, whose already potassium-rich soils and shallow water tables are at risk of being contaminated by “fertigation”, admitted Valsechi, an agronomist dedicated to sugarcane since his graduation in 1980.
The varieties developed by the network, identified by the acronym RB, now cover 60 percent of Brazil’s sugarcane area and have contributed to raising productivity to 85 tons per hectare, with cases of up to 150 tons, said Vieira. Thirty-five years ago, an average of 50 tons per hectare was not reached.