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ABSTRACT: Brewer’s spent grain components (cellulose, hemicellulose and lignin) were fractionated in a two-step chemical pretreatment
process using dilute sulfuric acid and sodium hydroxide solutions. The cellulose pulp produced was hydrolyzed with a cellulolytic
complex, Celluclast 1.5L, at 45°C to convert the cellulose into glucose. Several conditions were examined: agitation speed
(100, 150 and 200rpm), enzyme loading (5, 25 and 45FPU/g substrate), and substrate concentration (2, 5 and 8% w/v), according
to a 23 full factorial design aiming to maximize the glucose yield. The obtained results were interpreted by analysis of variance
and response surface methodology. The optimal conditions for enzymatic hydrolysis of brewer’s spent grain were identified
as 100rpm, 45FPU/g and 2% w/v substrate. Under these conditions, a glucose yield of 93.1% and a cellulose conversion (into
glucose and cellobiose) of 99.4% was achieved. The easiness of glucose release from BSG makes this substrate a raw material
with great potential to be used in bioconversion processes.
Cellulose 04/2012; 15(5):711-721. · 3.60 Impact Factor
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ABSTRACT: The aim of this study is to analyze the effects of low-level laser therapy (LLLT) on the regeneration of the sciatic nerve in rats following a complete nerve resection. Male Wistar rats were divided into a control injury group, injury groups irradiated with a 660-nm laser at 10 or 50 J/cm(2), and injury groups irradiated with an 808-nm laser at 10 or 50 J/cm(2). Treatment began 24 h following nerve resection and continued for 15 days. Using the sciatic functional index (SFI), we show that the injured animals treated with 660 nm at 10 and 50 J/cm(2) had better SFI values compared with the control injury and the 808-nm groups. Animals irradiated with the 808-nm laser at 50 J/cm(2) show higher values for fiber density than do control animals. In addition, axon and fiber diameters were larger in animals irradiated with 660 nm at 50 J/cm(2) compared to the control group. These findings indicate that 660-nm LLLT is able to provide functional gait recovery and leads to increases in fiber diameter following sciatic nerve resection.
Lasers in Medical Science 10/2011; 27(3):629-35. · 2.00 Impact Factor
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ABSTRACT: Different types of activated carbon were prepared by chemical activation of brewer's spent grain (BSG) lignin using H(3)PO(4) at various acid/lignin ratios (1, 2, or 3g/g) and carbonization temperatures (300, 450, or 600 degrees C), according to a 2(2) full-factorial design. The resulting materials were characterized with regard to their surface area, pore volume, and pore size distribution, and used for detoxification of BSG hemicellulosic hydrolysate (a mixture of sugars, phenolic compounds, metallic ions, among other compounds). BSG carbons presented BET surface areas between 33 and 692 m(2)/g, and micro- and mesopores with volumes between 0.058 and 0.453 cm(3)/g. The carbons showed high capacity for adsorption of metallic ions, mainly nickel, iron, chromium, and silicon. The concentration of phenolic compounds and color were also reduced by these sorbents. These results suggest that activated carbons with characteristics similar to those commercially found and high adsorption capacity can be produced from BSG lignin.
Bioresource technology 12/2009; 101(7):2450-7. · 4.25 Impact Factor
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ABSTRACT: The aim of this study was to compare the outcomes of nerve autografts (GRF) and venous grafts containing mononuclear bone marrow cells (BMCs) in sciatic nerve-lesioned rats. Control animals underwent sham operations (SHAM), received empty venous grafts (EPV), or received venous grafts containing BMC vehicle (AGR). Outcome was evaluated through sciatic functional index (SFI), morphometric and morphologic analyses of the nerve distal to the lesion, and the number of spinal cord motor neurons positive for the retrograde tracer, Fluoro-Gold. All groups exhibited poor results in SFI when compared to SHAM animals throughout the postoperative period. All groups also had a significantly greater fiber density, decreased fiber diameter, and decreased motor neuron number than the SHAM group. No significant difference between the GRF and BMC groups was observed in any of these parameters. On the other hand, vessel density was significantly higher in BMC than all other groups. BMC-containing venous grafts are superior to nerve autografts in increasing vessel density during sciatic nerve regeneration.
Journal of Neuroscience Methods 06/2008; 170(1):16-24. · 1.98 Impact Factor
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ABSTRACT: Chemically pre-treated brewer's spent grain was saccharified with cellulase producing a hydrolysate with approx. 50 g glucose l(-1). This hydrolysate was used as a fermentation medium without any nutrient supplementation by Lactobacillus delbrueckii, which produced L-lactic acid (5.4 g l(-1)) at 0.73 g g(-1) glucose consumed (73% efficiency). An inoculum of 1 g dry cells l(-1) gave the best yield of the process, but the pH decrease affected the microorganism capacity to consume glucose and convert it into lactic acid.
Biotechnology Letters 01/2008; 29(12):1973-6. · 1.68 Impact Factor
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ABSTRACT: Different types of activated carbon were prepared by chemical activation of brewer’s spent grain (BSG) lignin using H3PO4 at various acid/lignin ratios (1, 2, or 3 g/g) and carbonization temperatures (300, 450, or 600 °C), according to a 22 full-factorial design. The resulting materials were characterized with regard to their surface area, pore volume, and pore size distribution, and used for detoxification of BSG hemicellulosic hydrolysate (a mixture of sugars, phenolic compounds, metallic ions, among other compounds). BSG carbons presented BET surface areas between 33 and 692 m2/g, and micro- and mesopores with volumes between 0.058 and 0.453 cm3/g. The carbons showed high capacity for adsorption of metallic ions, mainly nickel, iron, chromium, and silicon. The concentration of phenolic compounds and color were also reduced by these sorbents. These results suggest that activated carbons with characteristics similar to those commercially found and high adsorption capacity can be produced from BSG lignin.
Bioresource Technology.
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ABSTRACT: The present study describes the precipitation of lignin by acidification of a black liquor (pH 12.56 and 12.44 g/l soluble lignin) produced by soda pulping of brewer’s spent grain. Sulfuric acid was added to the liquor to decrease the pH, forming a lignin-rich precipitate. Ten pH values (varying from 12.56 to 2.15) were studied. The lignin mass precipitated for each pH condition was determined, and the obtained liquors were evaluated regarding the color and concentration of soluble lignin. Some phenolic acids (vanillic, syringic, p-hydroxybenzoic, ferulic and p-coumaric) were quantified in the liquors to verify their removal profiles as a function of the pH alteration. Significant lignin precipitation was only observed at pH < 7.7. At pH 2.15 the concentration of soluble lignin was reduced to 2.31 g/l (removal of 81.43%) and the color of the liquor was strongly modified from dark brown to pale yellow. The phenolic compounds concentration was reduced in different proportions (from 74.4% to 32.1%), suggesting that each lignin derived compound is differently affected by the pH alteration.
Carbohydrate Polymers.
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ABSTRACT: A cellulose pulp obtained by chemical pre-treatment of brewer's spent grain was saccharified by a commercial cellulase preparation and the produced hydrolysate (50 g/l glucose) was fermented to lactic acid by Lactobacillus delbrueckii. The effects of pH control and nutrient supplementation of the hydrolysate on fermentation performance were investigated. Addition of 5 g/l yeast extract enhanced the lactic acid volumetric productivity that attained 0.53 g/l h, value 18% higher than that obtained from non-supplemented hydrolysate. Addition of the MRS broth medium components (except the carbon source) was still better, providing a productivity of 0.79 g/l h. In all the cases, the lactic acid yield factor was of 0.7 g/g glucose consumed, but the fermentations stopped after 24 h due to the pH drop from 6.0 to 4.2, resulting in large amounts of residual glucose (38–41 g/l). Fermentation runs pH-controlled at 6.0 gave better results than those where the initial pH was not further controlled. The best result, 35.54 g/l lactic acid (0.99 g/g glucose consumed) was obtained during the pH-controlled fermentation of hydrolysate medium supplemented with MRS components. The volumetric productivity at the end of this fermentation was 0.59 g/l h, with a maximum of 0.82 g/l h during the first 12 h.
Biochemical Engineering Journal.
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ABSTRACT: Enzymatic hydrolysis of brewer's spent grain in three different forms: original (untreated), pretreated by dilute acid (cellulignin), and pretreated by a sequence of dilute acid and dilute alkali (cellulose pulp), was studied to verify the effect of hemicellulose and lignin on cellulose conversion into glucose. The hydrolysis was carried out using a commercial cellulase concentrate (Celluclast 1.5 L) in an enzyme/substrate ratio of 45 FPU/g, 2% (w/v) substrate concentration, 45 °C for 96 h. According to the results, the cellulose hydrolysis was affected by the presence of hemicellulose and/or lignin in the sample. The cellulose conversion ratio (defined as glucose yield + cellobiose yield) from cellulignin was 3.5-times higher than that from untreated sample, whereas from cellulose pulp such value was 4-times higher, correspondent to 91.8% (glucose yield of 85.6%). This best result was probably due to the strong modification in the material structure caused by the hemicellulose and lignin removal from the sample. As a consequence, the cellulose fibers were separated being more susceptible to the enzymatic attack. It was concluded that the lower the hemicellulose and lignin contents in the sample, the higher the efficiency of cellulose hydrolysis.
Enzyme and Microbial Technology.
