Bagasse of Agave tequilana (BAT) is the residual lignocellulosic waste that remains from tequila production. In this study we characterized the chemical composition of BAT, which was further saccharified and fermented to produce ethanol. BAT was constituted by cellulose (42%), hemicellulose (20%), lignin (15%), and other (23%). Saccharification of BAT was carried out at 147 °C with 2% sulfuric acid for 15 min, yielding 25.8 g/l of fermentable sugars, corresponding to 36.1% of saccharificable material (cellulose and hemicellulose contents, w/w). The remaining lignocellulosic material was further hydrolyzed by commercial enzymes, ~8.2% of BAT load was incubated for 72 h at 40 °C rendering 41 g/l of fermentable sugars corresponding to 73.6% of the saccharificable material (w/w). Mathematic surface response analysis of the acid and enzymatic BAT hydrolysis was used for process optimization. The results showed a satisfactory correlation (R (2) = 0.90) between the obtained and predicted responses. The native yeast Pichia caribbica UM-5 was used to ferment sugar liquors from both acid and enzymatic hydrolysis to ethanol yielding 50 and 87%, respectively. The final optimized process generated 8.99 g ethanol/50 g of BAT, corresponding to an overall 56.75% of theoretical ethanol (w/w). Thus, BAT may be employed as a lignocellulosic raw material for bioethanol production and can contribute to BAT residue elimination from environment.

Bioethanol is among the most promising of biofuels because it has an energy content similar to gasoline while generating lower pollutant emissions than gasoline. But, in order to be used as an automotive fuel mixed with gasoline, ethanol must have less than 0.5 wt % of water. To achieve required ethanol purity, in light of the fact that the ethanolÀwater mixture forms an azeotrope, unconventional separation techniques such as extractive distillation or azeotropic distillation are necessary. However, the purification of ethanol using conventional distillation followed by extractive distillation has the disadvantage of high cost of services. Thus, this study proposes alternative hybrid systems using liquidÀliquid extraction and extractive distillation. The use of n-dodecane as entrainer for liquidÀliquid extraction and glycerol as entrainer for extractive distillation has been considered. The proposed systems are analyzed and a comparison is done on their performance in terms of energy and total annual cost. It has been found that the hybrid scheme presents both lower total energy consumption and lower total annual cost as compared to the traditional purification scheme with conventional distillation and extractive distillation.

Abstract:Lignin is an abundant component in biomass that can be used a feedstock for producing several value-added products, including biofuels. However, lignin is a complex molecule (involving in its structure three types of phenylpropane units: coumaryl, coniferyl and sinapyl), which is difficult to implement in any process simulation task. The lignin from softwood is formed mainly by coniferyl units; therefore, in this work the use of the guaiacol molecule to model softwood lignin in the simulation of the syngas process (H2 + CO) is proposed. A Gibbs reactor in ASPEN PLUS ® was feed with ratios of water and guaiacol from 0.5 to 20. The pressure was varied from 0.05 to 1.01 MPa and the temperature in the range of 200-3200 °C. H2, CO, CO2, CH4, O2 and C as graphite were considered in the output stream. The pressure, temperature and ratio water/guaiacol conditions for syngas production for different H2/CO ratio are discussed. The obtained results allow to determine the operating conditions to improve the syngas production and show that C as graphite and water decomposition can be avoided. OPEN ACCESSEnergies 2015, 8 6706

Fungal strains identified by phylogenetic analysis of the ITS rDNA region as (CMU-TA01), (CMU-84/13), and sp. (CMU-47/13) are able to grow on and bleach kraft pulp (KP) in a simple solid-state fermentation (SSF) assay conducted in Petri dishes. Kappa number reductions obtained with sp. (48.3%), (43%), and. (39.3%), evidence their capability for lignin breakdown. Scanning electron microscopy images of KP fibers from SSF assays demonstrated increased roughness and striation, evidencing significant cell wall modification. produces laccase (Lac), manganese peroxidase (MnP), and lignin peroxidase (LiP) in potato dextrose broth (PDB), PDB + CuSO, and PDB + KP, whereas sp. and showed no Lac and low LiP activities in all media. Compared to PDB, the highest increase in Lac (7.25-fold) and MnP (2.37-fold) activities in PDB + CuSO occur in ; for LiP, the greatest changes (6.95-fold) were observed in. Incubation in PDB + KP shows significant increases in Lac and MnP for , MnP and LiP for sp., and none for . SSF assays in Petri plates are a valuable tool to select fungi that are able to delignify KP. Here, delignification by sp. of this substrate is reported for the first time, and MnP activity was strongly associated with the delignification ability of the studied strains. The obtained results suggest that the studied fungal strains have biotechnological potential for use in the paper industry.

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