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Biofuels

Magnetic power

Electromagnets installed in the fermentation process of sugarcane juice increase the production of ethanol

buenoSix small, powerful electromagnets, strategically distributed around a stainless steel tube through which sugarcane juice flows, as well as the yeasts used in the fermentation of ethanol, have resulted in a 17% increase in yield versus the conventional process, thanks to a reduction in the amount of time this stage of the process takes. “The traditional fermentation process in the control experiment took 15 hours; using electromagnets attached to the bio-reactor cut this time to 12 hours,” says professor Ranulfo Monte Alegre, from the School of Food Engineering at the State University of Campinas (Unicamp). Professor Monte Alegre is the project coordinator; the team also includes four Cuban researchers: Victor Haber-Perez, Oselys Rodriguez Justo, Alfredo Fong Reyes and David Chacón Alvarez, from the CNEA, the National Center of Applied Electromagnetism of the Oriente University in Cuba.

“The increase in production was possible because the magnetic field changed the yeast’s metabolism,” says Monte Alegre. The researchers believe that the magnetic field might influence the potential of the cell membranes and consequently alter their permeability when the nutrients are passing through. “If the permeability increases, the transportation of the substrate into the cell also increases and the Saccharomyces cerevisiae yeast, used in fermentation, consumes this substrate faster, which results in higher production of ethanol,” explains the professor. Although the researchers have demonstrated these results, these biological effects of electromagnetic fields have not been entirely explained. Another hypothesis attributes the capacity of affecting enzymes – which are the biological catalysts – to the electromagnetic field, which might make them more suitable to react with the substrate, in the case of sugar, and with other compounds in the process.

“This could be the effect of the membrane or of the enzymes or of both at the same time,” says Monte Alegre. “We must carry out more in-depth biochemical studies together with multidisciplinary teams, comprised of engineers, biologists, biochemists, microbiologists and biophysicists,” adds Haber-Perez, a professor of food engineering at the Barretos Educational Foundation, in the State of São Paulo. Haber-Perez is the author of an article on this topic that came out last October in Biotechnology Progress, published by the American Chemistry Society.

Cell growth
The research that led to an increase in ethanol production began in the early nineties, when CNEA was created in Cuba. “When we set up the bio-electromagnetism department, we already knew that high-frequency and high-intensity electromagnetic fields could affect biological systems,” says Haber-Perez. The group’s primary objective was to study the effects of extremely low frequency and low intensity frequency fields. “Through this study, we found that bacterial cell growth of bacteria and yeasts could be altered, inhibited or accelerated, depending on the field being applied,” he says “The microorganisms respond to specific frequency, intensity, and time exposure parameters, and these conditions determine whether cell growth will be inhibited or accelerated; they even influence the production of a metabolite (the intermediary compound of the enzymatic reactions) of interest.”

The research begun in Cuba was re-initiated in 2000, when researcher Alfredo Fong Reyes went to Unicamp thanks to a post-doctoral grant from Capes, in order to work with magnetic field applications on alcohol fermentation under the supervision of professor Ranulfo Monte Alegre. When Fong Reyes returned to Cuba, Haber-Perez, who was doing a doctorate in chemical engineering at Unicamp and who had also been involved with the study, decided to continue the project. “A number of published studies focus on the application of magnetic fields in several fermentation processes, but in all of them the field generator systems had been placed around the fermenting equipment,” says Monte Alegre. “This has worked on a small scale, but it becomes unfeasible when it is expanded to a 100 cubic meter fermenting device,” he says. In the Unicamp study, the culture medium, including the substrate and the yeast, is recycled externally through a stainless steel tube that is crossed by the magnetic field, and only then returns to the fermenting device.

As the research was conducted on a laboratory scale, new studies are required to re-configure the magnetic field generator systems for a pilot plant and ultimately for industrial scale. “The high point was the development of national, non-conventional technology to increase ethanol production,” says Haber-Perez. The publication of the research in the website of Technology Review, a journal published by the Massachusetts Institute of Technology/MIT, drew the attention of both the international scientific community and the business community. “I was contacted from abroad several times, including a contact from a US company interested in learning more about our technology and financing its further study. The possibility of applying it to ethanol produced from corn and biomass (pulp residues) was one of the most frequent questions.”

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