Effect Of Steam Explosion Pretreatment Research Articles

Effect of Steam Explosion Pretreatment on Bamboo for Enzymatic Hydrolysis and Ethanol Fermentation

Based on the steam explosion pretreatment that has been applied to other types of lignocellulosic biomass, the steam explosion pretreatment of bamboo, along with a study of the chemical compositions and enzymatic hydrolyzability of substrates, was conducted. The results show that steam explosion pretreatment can greatly enhance the cellulose-to-glucose conversion yield after enzymatic hydrolysis, which is sometimes affected by bamboo age and steam explosion conditions. When the steam explosion pretreatment conditions were 2.0 MPa (pressure) and 4 min (time), the cellulose-to-glucose conversion yield of 2-year-old bamboo substrate was 62.5%. However, the cellulose-to-glucose conversion yield of bamboo substrates after direct (without steam explosion pretreatment) sodium chlorite/acetic acid delignification was 93.1%. Fermentation of enzymatic hydrolyzates with Saccharomyces cerevisiae resulted in about 88.1% to 96.2% of the corresponding theoretical ethanol yield after 24 h.

Steam explosion pretreatment of wheat straw to improve methane yields: Investigation of the degradation kinetics of structural compounds during anaerobic digestion

Wheat straw can serve as a low-cost substrate for energy production without competing with food or feed production. This study investigated the effect of steam explosion pretreatment on the biological methane potential and the degradation kinetics of wheat straw during anaerobic digestion. It was observed that the biological methane potential of the non steam exploded, ground wheat straw (276lNkgVS−1) did not significantly differ from the best steam explosion treated sample (286lNkgVS−1) which was achieved at a pretreatment temperature of 140°C and a retention time of 60min. Nevertheless degradation speed was improved by the pretreatment. Furthermore it was observed that compounds resulting from chemical reactions during the pretreatment and classified as pseudo-lignin were also degraded during the anaerobic batch experiments. Based on the rumen simulation technique, a model was developed to characterise the degradation process.

Effect of steam explosion pretreatment with ultra-high temperature and pressure on effective utilization of softwood biomass

Effective utilization process of not only cellulose but also lignin contained in softwood biomass into useful fuel and materials was developed using steam explosion with ultra-high temperature and pressure steam, extraction and various conversion methods. The conversion of softwood biomass into useful materials was studied for the effective utilization of its components such as cellulose, water soluble material, methanol soluble lignin, and Klason lignin. The cellulose, water soluble material, methanol soluble lignin, and Klason lignin were converted into useful fuel and materials, i.e. ethanol, antioxidant material, lignin epoxy resin, and activated carbon, respectively. 49.6 g of glucose or 17.4 g of ethanol was obtained from 100 g of steam-exploded product treated at a steam pressure of 45 atm and 3 min. Water soluble material had a comparatively high antioxidant activity and methanol soluble lignin was converted into a cured epoxy resin with heat-resisting property for solder demanded in the electronic material field.

Effect of Steam Explosion Pretreatment and Microbial Fermentation on Degradation of Corn Straw

The effects of steam explosion (2.5 MPa, 200s) and Trichoderma koningii (T. koningii) fermentation on corn straw degradation were evaluated according to straw degradation and enzyme activity in the fermented products. The results showed that the steam explosion pre-treatment for corn straw could reduce the contents of cellose, hemicellulose and lignin by 8.47%, 50.45% and 36.65%, respectively (P<0.05). After the pretreated corn straw with steam explosion was fermented by T. koningii for 6 days, the contents of cellulose and hemicellulose in the fermented straw were decreased by 19.37% and 63.54%, compared with the original corn straw (P<0.05); decreased by 11.83% and 26.41%, compared with the exploded straw (P<0.05). The filter paper cellulase, CMCase and amylase protease protease protease;activities in the fermented products were 356.39,5 599.90 and 834.00 U/g, respectively. It is concluded that the corn straw pre-treated by steam explosion and followed by T. koningii fermentation for 6 days seems to be a new prospective method for corn straw degradation and application.

Effect of steam explosion pretreatment on treatment with Pleurotus ostreatus for the enzymatic hydrolysis of rice straw

The effects of steam explosion (1.5 MPa, 1 min) on the treatment of rice straw with Pleurotus ostreatus were evaluated in terms of the change in composition of the components and the susceptibility to enzymatic hydrolysis. When rice straw was pretreated with a steam explosion prior to biological treatment, the treatment time required for obtaining a 33% net glucose yield was reduced to 36 days from 60 days. The reduction is probably due to loosening of networks of Klason lignin with sugar moieties and partial collapse of the structure during the biological treatment.

Influence of steaming explosion time on the physic-chemical properties of cellulose from Lespedeza stalks ( Lespedeza crytobotrya)

The synergistic effect of steam explosion pretreatment and sodium hydroxide post-treatment of Lespedeza stalks ( Lespedeza crytobotrya) has been investigated in this study. In this case, Lespedeza stalks were firstly exploded at a fixed steam pressure (22.5 kg/m 2) for 2–10 min. Then the steam-exploded Lespedeza stalks was extracted with 1 M NaOH at 50 °C for 3 h with a shrub to water ratio of 1:20 (g/ml), which yielded 57.3%, 53.1%, 55.4%, 52.8%, 53.2%, and 56.4% (% dry weight) cellulose rich fractions, comparing to 68.0% from non-steam-exploded material. The content of glucose in cellulose rich residues increased with increment of the steaming time and reached to 94.10% at the most severity. The similar increasing trend occurred during the dissolution of hemicelluloses. It is evident that at shorter steam explosion time, autohydrolysis mainly occurred on the hemicelluloses and the amorphous area of cellulose. The crystalline region of cellulose was depolymerized under a prolonged incubation time. The characteristics of the cellulose rich fractions in terms of FT-IR and CP/MAS 13C NMR spectroscopy and thermal analysis were discussed, and the surface structure was also investigated by SEM.

Physicochemical characteristics of densified untreated and steam exploded poplar wood and wheat straw grinds

The effect of steam explosion pretreatment, process (die) temperature, feedstock particle size, and moisture content was evaluated on the physical quality of pellets produced from poplar wood and wheat straw. Following feedstock preparation, which involved either pretreatment and moisture conditioning (9 and 15%, wet basis) or grinding (0.8 and 3.2 mm hammer mill screens) and moisture conditioning, the materials were compressed in a plunger–die assembly with a force of 4000 N. The resulting pretreated pellets had a higher density and tensile strength than the untreated. Also, the pretreated pellets experienced a dimensional reduction after 14 days, whereas the untreated pellets expanded in the diametric and longitudinal axes. Pretreated wheat straw generally had a higher pellet density, higher tensile strength, and higher dimensional reduction than the pretreated poplar pellets. Conversely, the untreated poplar pellets had a higher pellet physical quality than the untreated wheat straw pellets. Increasing the die temperature (from 70 to 100 °C) and decreasing the feedstock particle size (from 3.2 to 0.8 mm) increased pellet physical quality. The effect of moisture content on pellet physical quality varied with the levels of other factors (die temperature and particle size). Using Fourier Transform Infrared Photoacoustic Spectroscopy, it was found that the lignocellulosic structure was disrupted by pretreatment. The resulting higher relative percentage, and availability, of lignin was attributed to the increased quality of the pretreated feedstock pellets.

Effect of steam explosion on biodegradation of lignin in wheat straw

The effect of steam explosion pretreatment on biodegradation of lignin in wheat straw was studied in this paper. Through experiments and analysis, 0.8 MPa operation pressure and 1:20 wheat straw to water ratio are optimum for destroying lignin and the maximum of lignin loss rate is 19.94%. After steam explosion pretreatment, the wheat straw was retted by Trametes versicolor for 40 days. Biodegradation rate of lignin was tested and the maximum of 55.40% lignin loss rate was found on day 30. During the whole process of both steam explosion pretreatment and biodegradation, 75.34% lignin was degraded, without steam explosion the biodegradation of raw material the degradation rate of lignin was 31.23% only. FT-IR spectroscopy, TGA and SEM were used for further validating the results of biodegradation.

Effect of steam explosion treatment on the physico-chemical characteristics and enzymic hydrolysis of poplar cell wall components

The purpose of this study was to determine the effect of steam explosion pretreatment on pore size distribution and enzymic hydrolysis of poplar wood chips under various conditions (duration and temperature of treatment, pH impregnation). The measurements showed an increase in the available surface area with the severity of treatment and a good correlation with the initial rate of enzymic hydrolysis. This increase in enzymic hydrolysis can be explained by the removal of the hemicelluloses, but also by the melting and agglomeration of the depolymerized lignin, as shown on electron micrographs of ultrathin cross-sections.

On the use of an adsorption model to represent the effect of steam explosion pretreatment on the enzymatic hydrolysis of lignocellulosic substances

On the use of an adsorption model to represent the effect of steam explosion pretreatment on the enzymatic hydrolysis of lignocellulosic substances

Effect of steam explosion pretreatment on pore size and enzymatic hydrolysis of poplar

The purpose of this study was to determine the effect of batch steam explosion pretreatment on the rate of subsequent enzymatic hydrolysis of hybrid poplar wood. This pretreatment was found to be effective as indicated by the fact that for many of the pretreatment conditions studied the glucose yield obtained after 24 h of enzymatic hydrolysis using enzymes from Trichoderma reesei And Aspergillus niger is in excess of 90% of the potential, whereas the corresponding yield from unpretreated substrate is only 15%. The effect of pretreatment is believed to be primarily due to the increase in pore surface area accessible to enzyme molecules. Measurements show a considerable increase in pore volume available to 5–9 nm solute probes. Pretreated wood that was subsequently oven-dried hydrolysed poorly and showed a reduction in available pore volume after drying. Xylans are readily hydrolysed to xylose during pretreatment and owing to decomposition the amount of xylose in solution after steam pretreatment decreases as the severity of the reaction conditions increases; the converse is true for glucose. We conclude that steam explosion pretreatment can be effective on hybrid poplar and that the quantitative results obtained can be used for process design.