Ethanol organosolv pretreatment of sugarcane bagasse assisted by organic acids and supercritical carbon dioxide.

The scCO2-assisted organosolv pretreatment of sugarcane bagasse was carried out using aqueous ethanol and organic acid catalysts. Variables involved were temperature (150-190 °C), time (0-60 min), type of catalyst (acetic, citric, and oxalic acids), amount of CO2 (25-50 g), ethanol titer in water (0-80 vol%), and catalyst concentration (0.5 to 1.5 % w·v-1). The best delignification (86 wt%) and glucan retention (89 wt%) were achieved at 170 °C for 15 min using 60 vol% ethanol in water, 1 wt% oxalic acid, and 25 g CO2. Organic acid esterification was a limitation for pretreatment operations using ethanol titers above 60 vol%. Enzymatic hydrolysis of pretreated materials at 1 % (w·v-1) glucans released 74.3 ± 0.2 % glucose in 96 h using Cellic CTec3 (Novozymes) at 9.89 FPU·gglucans-1. The concentrated pretreatment liquor allowed lignin recovery by water precipitation in high yields, while the aqueous supernatant contained low levels of fermentation inhibitors.

Steam explosion pretreatment of oil palm empty fruit bunches (EFB) using autocatalytic hydrolysis: A biorefinery approach.

The oil palm empty fruit bunches (EFB) are an attractive source of carbon for the production of biochemical products, therefore, the aim of this work is to analyze the effect of the steam explosion (SE) pretreatment under autocatalytic conditions on EFB using a full experimental design. Temperature and reaction time were the operational variables studied. The EFB treated at 195°C for 6 min showed an increase of 34.69% in glycan (mostly cellulose), and a reduction of 68.12% in hemicelluloses, with increased enzymatic digestibility to 33% producing 4.2 g L(-1) of glucose. Scanning electron micrographs of the steam treated EFB exhibited surface erosion and an increased fiber porosity. Fourier transform infrared spectroscopy showed the solubilization of hemicellulose and modification of cellulose in treated EFB.

Kinetics of enzymatic hydrolysis of olive oil in batch and fed-batch systems.

This work reports experimental data, kinetic modeling, and simulations of enzyme-catalyzed hydrolysis of olive oil. This reaction was performed in batch system and an ordered-sequential Bi Bi model was used to model the kinetic mechanism. A fed-batch system was proposed and experimental data were obtained and compared to the simulated values. The kinetic model used was able to correlate the experimental data, in which a satisfactory agreement between the experimental data and modeling results was obtained under different enzyme concentration and initial free water content. Therefore, the modeling allowed a better understanding of the reaction kinetics and affords a fed-batch simulation for this system. From the results obtained, it was observed that the fed-batch approach showed to be more advantageous when compared to the conventional batch system.