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De Souza R.B.,Federal University of Pernambuco | De Souza R.B.,Laboratory of Bioprocessing | Santos B.M.D.,Federal University of Pernambuco | De Fatima Rodrigues De Souza R.,Federal University of Pernambuco | And 6 more authors.
Journal of Industrial Microbiology and Biotechnology | Year: 2012

This work describes the effects of the presence of the yeast Dekkera bruxellensis and the bacterium Lactobacillus vini on the industrial production of ethanol from sugarcane fermentation. Both contaminants were quantified in industrial samples, and their presence was correlated to a decrease in ethanol concentration and accumulation of sugar. Then, laboratory mixed-cell fermentations were carried out to evaluate the effects of these presumed contaminants on the viability of Saccharomyces cerevisiae and the overall ethanol yield. The results showed that high residual sugar seemed the most significant factor arising from the presence of D. bruxellensis in the industrial process when compared to pure S. cerevisiae cultures. Moreover, when L. vini was added to S. cerevisiae cultures it did not appear to affect the yeast cells by any kind of antagonistic effect under stable fermentations. In addition, when L. vini was added to D. bruxellensis cultures, it showed signs of being able to stimulate the fermentative activity of the yeast cells in a way that led to an increase in the ethanol yield.. © Society for Industrial Microbiology and Biotechnology 2012.

Reis A.L.S.,Laboratory of Bioprocessing | Damilano E.D.,Federal University of Pernambuco | Menezes R.S.C.,Federal University of Pernambuco | de Morais M.A.,Laboratory of Bioprocessing | de Morais M.A.,Federal University of Pernambuco
Industrial Crops and Products | Year: 2016

In previous work we showed that the yeast Dekkera bruxellensis (strain GDB 248) is capable of assimilating cellobiose and converting this sugar to ethanol, a characteristic that may help in reducing the cost of biomass hydrolysis with commercial enzyme. In the present work we tested the efficiency of ethanol production by this yeast from bagasse of sugarcane (SCB) and sweet sorghum (SSB) after alkaline H2O2 pretreatment and enzymatic hydrolysis treatment. SSB contained less lignin and ashes and more waxes than SCB, resulting in more efficient pretreatment and enzyme hydrolysis, as evidenced by chemical and physical analysis. Glucose and cellobiose were released from cellulose, as well as xylose from the remaining hemicellulose. The hexoses were completely consumed with final yields of 0.42 (±0.04) g/g for SCB and 0.44 (±0.03) g/g for SSB. Acetate was not produced, which indicated that the fermentations were carried out under anaerobic condition. This yeast was capable of metabolising cellobiose for ethanol production, which therefore proves to be a promising industrial microorganism for the production of second-generation ethanol. © 2016 Elsevier B.V.

Dutra E.D.,Federal University of Pernambuco | Neto A.G.B.,Genetech Research | de Souza R.B.,Laboratory of Bioprocessing | de Souza R.B.,Genetech Research | And 5 more authors.
Sugar Tech | Year: 2013

The decline in the use of fossil fuels in the future is due to the gradual depletion of their reserves and related environmental issues. Biofuels including ethanol are presented as a renewable alternative to fossil fuels. However, ethanol production, generally from sugarcane demands the use of agricultural land and other natural resources, with emphasis on water and other nutrients. Sorghum is tolerant to drought. The purpose of this study was to evaluate the potentiality of eight sweet sorghum cultivars in order to expand the ethanol production to areas with limited supply of water, not suitable for sugarcane which requires irrigation. The cultivars developed by breeding programs in the state of Pernambuco, Brazil, were analyzed for fermentation by industrial strain of Saccharomyces cerevisiae, at 33 °C, under static conditions for a period of 6 h. All assessed parameters showed some statistically significant differences among cultivars (p < 0.01), especially ethanol concentration (P) and the volumetric productivities (Qp) in the following order: Willey (P = 64.77 ± 4.4 g L-1 and Qp = 10.79 ± 0.74 g L-1 h-1), Wray (P = 59.10 ± 1.7 g L-1 and Qp = 9.85 ± 0.28 g L-1 h-1), BR 506 (P = 59.07 ± 1.3 g L-1 and Qp = 9.84 ± 0.21 g L-1 h-1) and SF 15 (54.40 ± 0.4 g L-1 and Qp = 9.07 ± 0.06 g L-1 h-1). The highest potentials for ethanol yield per hectare were observed for the cultivars SF 15 (3142.51 ± 428.47 L ha-1) and BR 506 (2193.95 ± 383.58 L ha-1). Therefore, the cultivars SF 15 and BR 506 seem to be very promising as an energy crop to be produced in areas with environmental conditions similar to Pernambuco. © 2013 Society for Sugar Research & Promotion.

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