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São Carlos, Brazil

Pinto A.S.S.,Federal University of Sao Carlos | Pereira S.C.,Embrapa Instrumentation | Ribeiro M.P.A.,Federal University of Sao Carlos | Farinas C.S.,Federal University of Sao Carlos
Bioresource Technology | Year: 2016

Rapid, efficient, and low-cost technologies for monitoring the fermentation process during second generation (2G) or cellulosic ethanol production are essential for the successful implementation of this process at the commercial scale. Here, the use of near-infrared (NIR) spectroscopy associated with partial least squares (PLS) regression was investigated as a tool for monitoring the production of 2G ethanol from lignocellulosic sugarcane residues including bagasse, straw, and tops. The spectral data was based on a set of 103 alcoholic fermentation samples. Models based on different pre-processing techniques were evaluated. The best root mean square error of prediction (RMSEP) values obtained in the external validation were around 3.02. g/L for ethanol and 6.60. g/L for glucose. The findings showed that the PLS-NIR methodology was efficient in accurately predicting the glucose and ethanol concentrations during the production of 2G ethanol, demonstrating potential for use in monitoring and control of large-scale industrial processes. © 2015 Elsevier Ltd. Source

Cunha F.M.,Federal University of Sao Carlos | Esperanca M.N.,Federal University of Sao Carlos | Zangirolami T.C.,Federal University of Sao Carlos | Badino A.C.,Federal University of Sao Carlos | Farinas C.S.,Embrapa Instrumentation
Bioresource Technology | Year: 2012

Sequential solid-state and submerged cultivation with sugarcane bagasse as substrate for cellulase production by . Aspergillus niger A12 was assessed by measuring endoglucanase activity. An unconventional pre-culture with an initial fungal growth phase under solid-state cultivation was followed by a transition to submerged fermentation by adding the liquid culture medium to the mycelium grown on solid substrate. For comparison, control experiments were conducted using conventional submerged cultivation. The cultures were carried out in shake flasks and in a 5-L bubble column bioreactor. An endoglucanase productivity of 57. ±. 13. IU/L/h was achieved in bubble column cultivations prepared using the new method, representing an approximately 3-fold improvement compared to conventional submerged fermentation. Therefore, the methodology proposed here of a sequential fermentation process offers a promising alternative for cellulase production. © 2012 Elsevier Ltd. Source

Farinas C.S.,Embrapa Instrumentation | Farinas C.S.,Federal University of Sao Carlos
Renewable and Sustainable Energy Reviews | Year: 2015

Solid-state fermentation (SSF) processes have enormous potential for many new applications using the bioconversion of agro-industrial residues into biofuels and other high value-added products. The agricultural sector is currently undergoing global expansion, especially in relation to crops used for energy production as a strategy to reduce dependence on petroleum and mitigate the effects of climate change. Consequently, a similar expansion is expected in the amounts of agricultural and forestry residues generated. The conversion of these lignocellulosic biomasses using enzymes is likely to be a key technology in future biorefineries. However, in order to make the enzymatic conversion of biomass commercially viable, it is necessary to improve the efficiency of (hemi)cellulolytic enzymes production and reduce the costs of the enzymatic cocktails employed. The focus of this review is on recent developments in SSF processes for enzymes production, and the application of such techniques in the bioenergy sector. An overview of the enzymes required for the conversion of biomass, important SSF process variables related to the production of (hemi)cellulolytic enzymes, the bioreactors that have been used for this purpose, and novel SSF configurations is provided. It is hoped that the information gathered together here will assist in the development of SSF processes that enable efficient future production of the enzymes required for the conversion of biomass. © 2015 Elsevier Ltd. All rights reserved. Source

De Mendonca V.R.,Federal University of Sao Carlos | Mourao H.A.J.L.,Federal University of Sao Carlos | Malagutti A.R.,Federal University of Vales do Jequitinhonha and Mucuri | Ribeiro C.,Embrapa Instrumentation
Photochemistry and Photobiology | Year: 2014

Despite photocatalytic degradation is studied generally focusing the catalyst, its interaction with the contaminant molecule plays a fundamental role in the efficiency of that process. Then, we proposed a comparative study about the photodegradation of two well-known dyes, with different acidity/basicity - Methylene Blue (MB) and Rhodamine B (RhB), catalyzed by TiO2 nanoparticles, varying both dye and photocatalyst concentrations. The results showed that the amphoteric character of MB molecules, even in a range of concentration of 5.0-10.0 mg L-1, did not imply in pH variation in solution. Therefore, it did not affect the colloidal behavior of TiO2 nanoparticles, independent of the relative dye/catalyst concentration. The acid-base character of RhB influenced the resultant pH of the solution, implicating in different colloidal behavior of the nanoparticles and consequently, in different degradation conditions according to dye concentration. As the isoelectric point of TiO2 is between the pH range of the RhB solutions used in this study, from 1.0 to 7.5 mg L -1, the resultant pH was the key factor for degradation conditions, from a well dispersed to an agglomerated suspension. Plot presenting the relation between photoinduced RhB photodegradation rate constant (k* = k'/[TiO2]) as a function of TiO2 photocatalyst and Rhodamine B initial concentration. © 2013 The American Society of Photobiology. Source

Giroto A.S.,Federal University of Sao Carlos | Fidelis S.C.,Federal University of Sao Carlos | Ribeiro C.,Embrapa Instrumentation
RSC Advances | Year: 2015

We report in this paper a strategy to prepare nanocomposite fertilizers based on the dispersion of hydroxyapatite (Hap) into urea and thermoplastic starch at nanoscale, where Hap was assumed as a model for poorly soluble phosphate phases, such as phosphate rocks. Our experiments revealed the role of particle agglomeration on the effective phosphate release, showing that Hap dispersion within two water-soluble matrices (urea and thermoplastic starch/urea) is an effective strategy to increase Hap solubility. Aspects such as matrix solubility, morphology and Hap loading were detailed studied. Also, these structures showed an interesting slow-release of urea, i.e., the materials were at the same time a system for faster release of poorly soluble phosphate phases and slow release of very soluble nitrogen source (urea). Our results support the development of a new class of smart fertilizers, with release properties tailored by nanostructure. © 2016 The Royal Society of Chemistry. Source

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