Pretreatment Of Corn Straw Research Articles

Preparation and Characteristics of Corn Straw-Co-AMPS-Co-AA Superabsorbent Hydrogel

In this study, the corn straw after removing the lignin was grafted with 2-acrylamido-2-methylpropanesulfonic acid (AMPS) to prepare sulfonated cellulose. The grafting copolymerization between the sulfonated cellulose and acrylic acid (AA) was performed using potassium persulfate and N,N′-methylenebisacrylamide as the initiator and crosslinking agent, respectively, to prepare corn straw-co-AMPS-co-AA hydrogels. The structure and properties of the resulting hydrogels were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, and dynamic rheometry. The effects of initiator, crosslinker, monomer neutralization degree, and temperature on the swelling ratio of the hydrogels were studied. The water retention, salt resistance, and recyclability of the corn straw-co-AMPS-co-AA hydrogels were also investigated. The optimum water absorptivity of the corn straw hydrogels was obtained at a polymerization temperature of 50 °C with 1.2% crosslinker, 1:7 ratio of the pretreated corn straw and AA, 2% initiator, and 50% neutralized AA.

The chemical properties and microbial community characterization of the thermophilic microaerobic pretreatment process

Thermophilic microaerobic pretreatment (TMP) was recently reported as an efficient pretreatment method of anaerobic digestion (AD). In this study, the chemical properties and microbial community were characterized to reveal how TMP working. Compared with thermophilic treatment under anaerobic condition (TMP0), cellulase activity obviously improved under microaerobic condition (TMP1), which was 10.9–49.0% higher than that of TMP0. Reducing sugar, SCOD and VFAs concentrations of TMP1 were 2.6–8.9%, 1.8–4.8% and 13.8–24% higher than those of TMP0, respectively. TMP gave obvious rise to phylum Firmicutes, which associated with extracellular enzymes production. The proportion of class Bacilli (belongs to phylum Firmicutes and mainly acts during hydrolysis) in TMP1 was 124.89% higher than that of TMP0, which reflected the greater hydrolytic ability under microaerobic condition. The improved abundance of phylum Firmicutes (especially class Bacilli, order Bacillales) under microaerobic condition could be the fundamental reason for the improved AD performance of thermophilic microaerobic pretreated corn straw.

Effects of thermo-chemical pretreatment plus microbial fermentation and enzymatic hydrolysis on saccharification and lignocellulose degradation of corn straw

In order to increase corn straw degradation, the straw was kept in the combined solution of 15% (w/w) lime supernatant and 2% (w/w) sodium hydroxide with liquid-to-solid ratio of 13:1 (mL/g) at 83.92°C for 6h; and then added with 3% (v/v) H2O2 for reaction at 50°C for 2h; finally cellulase (32.3FPU/g dry matter) and xylanase (550U/g dry matter) was added to keep at 50°C for 48h. The maximal reducing sugars yield (348.77mg/g) was increased by 126.42% (P<0.05), and the degradation rates of cellulose, hemicellulose and lignin in pretreated corn straw with enzymatic hydrolysis were increased by 40.08%, 45.71% and 52.01%, compared with the native corn straw with enzymatic hydrolysis (P<0.05). The following study indicated that the combined microbial fermentation and enzymatic hydrolysis could further increase straw degradation and reducing sugar yield (442.85mg/g, P<0.05).

Process intensification effect of ball milling on the hydrothermal pretreatment for corn straw enzymolysis

Enhancement of the cellulose accessibility is significant for biomass enzymatic hydrolysis. Here, we reported an efficient combined pretreatment for corn straw enzymolysis using ball milling and dilute acid hydrothermal method (a mixture solvent of H2O/ethanol/sulfuric acid/hydrogen peroxide liquid). The process intensification effect of ball milling on the pretreatment of the corn straw was studied through the comparative characterization of the physical–chemical properties of the raw and pretreated corn straw using FT-IR, BET, XRD, SEM, and HPLC analysis. The effect of the pretreatment temperature was also investigated. Furthermore, various pretreatment methods were compared as well. Moreover, the pretreatment performance was measured by enzymolysis. The results showed that ball milling had a significant process intensification effect on the corn straw enzymolysis. The glucose concentration was dramatically increased from 0.41 to 13.86mgmL−1 after the combined treatment of ball milling and hydrothermal. The efficient removal of lignin and hemicellulose and the enlargement of the surface area were considered to be responsible for this significant increase based on the intensive analysis on the main components and the physical–chemical properties of the raw and pretreated corn straw.

Hydrolysis of Straw in Ionic Liquids with Acid as Catalyst under Microwave Irradiation

With ionic liquids as solvents and corn straw as raw material, different processes of lignocellulose pretreatment with acid as catalyst were studied under conventional heating/microwave irradiation and the reducing sugar was measured. The results indicated that acid can accelerate hydrolysis reaction of corn straw into reducing sugar with ionic liquids as solvent, and microwave irradiation was more efficient in pretreatment of corn straw than conventional heating. The influences of different acid catalysts, the concentration of acid, temperature, mass ratio of straw/[Bmim]Cl, and the amount of refill water were mainly tested, and the optimum experimental conditions are thus determined.

Combined pretreatment using ozonolysis and ball milling to improve enzymatic saccharification of corn straw

Two clean pretreatments, ozonolysis (OZ) and planetary ball milling (BM) were applied separately and in combination to improve the enzymatic hydrolysis of corn straw. Pretreatment of corn straw by OZ and BM alone improved the enzymatic hydrolysis significantly, primarily through delignification and decrystallization of cellulose, respectively. When combined, OZ–BM and BM–OZ pretreatments made the enzymatic hydrolysis more efficient. The glucose and xylose yield of corn straw treated with OZ for 90min followed by BM for 8min (OZ90–BM8) reached to 407.8 and 101.9mg/g-straw, respectively under cellulase loading of 15FPU/g-straw, which was fivefold more than that of untreated straw. Under much lower cellulase loading of 1.5FPU/g-straw, the glucose and xylose yield of treated straw OZ90–BM8 remained at 416.0 and 108.4mg/g-straw, respectively, while the yield of untreated straw decreased. These findings indicate that the combined OZ–BM can be used as a promising pretreatment for corn straw.

Improved bioethanol production from corn stover by alkali pretreatment with a novel pilot-scale continuous microwave irradiation reactor

A novel continuous microwave irradiation (MWI) pilot-scale reactor was designed specifically for biomass pretreatment. To test the efficiency of this reactor, MWI-assisted alkali pretreatment of corn straw (CS) was investigated using a central composite design for the response surface methodology. With a processing capacity of 0.28 kg CS (dry matter, DM)/h, the optimal conditions were as follows: 4.50 kW, 30 min, and 3.50% NaOH (w/v). The glucose and ethanol production from the pretreated CS were 63.22 and 31.29 g/100 g DM, respectively. These values were 4.42 and 3.79 times higher, respectively, than those from untreated CS. Structural changes in the untreated/pretreated CS were identified by analyzing its chemical composition using X-ray diffraction (XRD), scanning electron microscopy (SEM) and fourier transform infrared spectroscopy (FTIR). In addition, the solid residue recovery ratio was demonstrated to be an indicator of the biomass bioconversion potential.

Effect of the combined physical and chemical treatments with microbial fermentation on corn straw degradation

In order to improve corn straw degradation, steam explosion, sodium hydroxide soaking and Aspergillus oryzae fermentation were used. The optimal sodium hydroxide pretreatment condition for lignin degradation was obtained. The degradation rates of hemicellulose, cellulose and lignin were 54.68%, 17.76% and 33.14% for the exploded straw (P<0.05); 67.92%, 2.44% (P>0.05) and 76.54% for the alkali-treated straw (P<0.05); 75.98%, 39.93% and 77.88% for the exploded and alkali-treated straw (P<0.05), respectively. The following microbial fermentation could degrade hemicellulose and cellulose further (P<0.05). Cellulase, amylase and protease activities produced during microbial fermentation in the pretreated corn straw were lower than that in the untreated one (P<0.05); however, glucose content was increased by microbial fermentation (P<0.05). It can be concluded that the combined treatments of steam explosion, sodium hydroxide and microbial fermentation will be a good method for straw degradation.

High Level of Cellulase and β-Glucosidase Production by T.reesei and T.koningii Combinations on Corn Straws of Alkali Pretreatment

In order to obtain high level of β-glucosidase and filter paper activity production, the screening of strain combinations and the characteristic of enzymes from co-culture were investigated. The results showed that both the β-glucosidase (0.347 U/ml) and FPA (3.21 U/ml) reached the highest level via co-culture of T.reesei and T.koningii with the corn straw of alkali pretreatment as fermentation substrate. After 72 h of fermentation, both two enzyme activities reached the highest level. And the optimal temperature and pH value were 55°C and 5.5, respectively. These two enzyme stability decreased rapidly when the temperatures exceeded 90°C. The conversion efficiency reached 0.652 g reducing sugar per g pretreated corn straw using the enzymes from these two fungi, which was 1.49-fold and 1.64-fold compared with those from T.reesei (0.439 g/g) and T.koningii (0.398 g/g). The present work demonstrated an effective way to develop an efficient system for the bioconversion of agricultural waste straws to sugar.

Microwave Pre-Treatment of Corn Straw and its Enzymatic Hydrolysis

To enhance enzymatic hydrolysis efficiency of the corn straw, a process microwave pretreatment of corn straw was optimized using response surface methodology (RSM). Estimated optimum parameters were as follows: water to corn straw ratio is 58:1, microwave power is 640w and processing time is 5 minutes. Under these conditions, a maximum enzyme hydrolysis ratio of corn straw (49.25%) after microwave pretreatment was reached.

The Study of the Dilute Acid Pretreatment Technology of Corn Stover and Rice Straw

Ethanol production from lignocellulosic materials provides an alternative energy production system. Dilute sulfuric acid pretreatment of corn straw and rice straw and enzymatic hydrolysis of cellulose were investigated in this study. The straw was pretreated at 121°C with different sulfuric acid concentrations (1, 2, 3, 4and 5%, v/v) and residence times (30, 60, and 90 min). The concentration and conversion of total reducing sugars were analyzed. Pretreatment residence time play a key role in increase glucose concentration comparing to sulfuric acid concentration. Cellulose remaining in the pretreated feedstock was highly digestible by cellulases from Trichoderma viride. The result that the saccharification yield of 72.38% and 82.84% from corn straw and rice straw by using 2% (v/v) acid pretreatment at 121°C for 60 min and saccharifying with cellulase preparations.

Construction and Evaluation of Recombinant Strains for Ethanol Production from Lignocellulosic Hydrolysate

The recombinant Z.mobilis CX was constructed. Its ethanol concentration and ethanol yield from 2% xylose at 36 h were 6.73 g/L and 82.3% of theoretical yield, respectively. The recombinant S.cerevisiae YB was constructed and was showed to utilize cellobiose as the sole carbon source for rapid growth and ethanol production. The maximum ethanol concentration 7.493 g/L and ethanol yield 77.4% of theoretical yield from 2% cellobiose were obtained at 24 h. Further, the preliminary results of SSF of pretreated corn straw demonstrated the potential of improving ethanol production and reducing the costs of cellose enzymes used by co-fermentation of CX and YB.

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&lt;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&lt;0.05); decreased by 11.83% and 26.41%, compared with the exploded straw (P&lt;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.

Biological hydrogen production from hydrogen-producing fermentative liquid steam-exploded pretreatment of corn straw

Biological hydrogen production from hydrogen-producing fermentative liquid steam-exploded pretreatment of corn straw

Biological hydrogen production from hydrogen-producing fermentative liquid steam-exploded pretreatment of corn straw

Biological hydrogen production from hydrogen-producing fermentative liquid steam-exploded pretreatment of corn straw