Abstract

Lignocellulosic feedstock has tremendous potential to sustain the renewable production of biofuels such as ethanol and butanol. Although lignocellulosic biomass is a storehouse of energy in the form of cellulose and hemicellulose, yet lignin acts as a barrier against their hydrolysis. A dilute acid pretreatment disintegrates the biomass complex and allows cellulolytic enzymes to hydrolyze cellulose and hemicelluloses in releasing fermentable sugars. The current study investigates the effect of different H2SO4 doses (0–2.5%) on the three lignocellulosic feedstock material, especially pinewood, timothy grass, and wheat straw at 121°C for 1 h. Furthermore, the pretreated feedstock was subjected to enzymatic hydrolysis using cellulase, β-glucosidase, and xylanase at 45°C for 72 h. The biomass hydrolysates containing monomeric sugars (glucose and xylose) were fermented using Saccharomyces cerevisiae and Clostridium beijerinckii for ethanol and butanol production, respectively. A comparative evaluation for the concentrations of ethanol and butanol, residual sugars as well as byproducts such as acetone, acetate, and butyrate from biomass hydrolysates was performed. Pinewood hydrolysate revealed high ethanol (24.1 g/L) and butanol (11.6 g/L) concentrations due to greater sugar content. In contrast to ethanol fermentation by S. cerevisiae, butanol fermentation by C. beijerinckii demonstrated low butanol levels in the hydrolysates due to butanol toxicity toward clostridia.

Abstract

The purpose of the study was to analyze the deposits in injectors with fuel mixture of 87 octane with percentages of anhydrous ethanol at 5 %, and 87 octane gasoline. The experimental phase was carried out in two ignition engine vehicles at a test height of 2810 msnm when traveling, each one, a distance of 3000 km inside the Metropolitan District of Quito. Two methods were applied: Stereoscopy or Vision for the analysis of the microfilters of the injectors, and the semiquantitative chemical analysis Scanning Electron Microscopy for the samples of the residues originated in the filters. In the case of Stereoscopy, in both vehicles, a reduction of clogging of the filters occurred when using gasoline with 5 % anhydrous ethanol. The Scanning Electron Microscopy allowed to conclude that there is a greater presence of the sulfur element with 4 % in the residues when using gasoline with 5 % ethanol, unlike 1 % in the waste when 87 octane gasoline is applied.

Abstract

Vanillin is commonly used as an additive in food, medicine and cosmetics, but its effect has not yet been studied in gastric injury. Therefore the effect of vanillin was studied in experimental gastric ulcer. Gastric secretion and acidity were studied in pylorus ligated rats. Ulcer index, levels of gastric mucus, malondialdehyde (MDA), myeloperoxidase activity (MPO), expression of nuclear factor kappa B (NF-κB) p65, and histopathological changes were determined in ethanol induced gastric ulcer. Pre treatment with vanillin significantly reduced gastric secretion (P < 0.001) and acidity (P < 0.0001) and gastric ulcer index scores (P < 0.001). and augmented the gastric mucosal defense. Vanillin significantly restored the depleted gastric wall mucus levels (P < 0.0001) induced by ethanol and also significantly attenuated ethanol induced inflammation and oxidative stress by the suppression of gastric MPO activity (P < 0.001), reducing the expression of NF-κB p65 and the increased MDA levels (P < 0.001). Vanillin was also effective in alleviating the damage to the histological architecture and the activation of mast cells induced by ethanol. Together the results of this study highlight the gastroprotective activity of vanillin in gastric ulcers of rats through multiple actions that include inhibition of gastric secretion and acidity, reduction of inflammation and oxidative stress, suppression of expression of NF-κB, and restoration of the histological architecture.