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The effect of phenolic compounds on hydrothermal oxidation of cellulose was studied using a batch reactor at 300 degrees C with H(2)O(2) as oxidant. Intermediate products, as well as the yields of acetic acid produced in the oxidation of cellulose, phenolic compounds, and cellulose-phenolic compound mixtures were examined. Phenolic compounds used were phenol, 1,4-benzenediol, 2-methoxy-4-methylphenol, and 2,6-di-tert-butyl-4-methylphenol. In the case of oxidation of cellulose-phenolic compound mixtures, (1) formic acid, a basic oxidation product from carbohydrates, decreased considerably, (2) 5-hydroxymethyl-2-furaldehyde and 2-furaldehyde, acid-catalyzed dehydration products from carbohydrates, appeared, and (3) the yield of acetic acid increased compared to that in the oxidation of cellulose. From these results, phenolic compounds seem to inhibit the oxidation of cellulose under hydrothermal conditions. The inhibition of the oxidation of cellulose by phenolic compounds seems to be related closer to the stability of phenolic compounds under oxidation conditions rather than the ease to remove phenolic hydrogen on the OH group. 相似文献
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M. Subhosh Chandra Buddolla Viswanath B. Rajasekhar Reddy 《Indian journal of microbiology》2007,47(4):323-328
The production of cellulolytic enzymes by Aspergillus niger on lignocellulosic substrates groundnut fodder, wheat bran, rice bran and sawdust in solid state fermentation in a laboratory
scale was compared. Czapek Dox liquid broth amended with cellulose (0.5%) was used to moisten lignocellulosic solid supports
for cultivation of Aspergillus niger. The production of filter paperase, carboxymethyl cellulase and -glucosidase were monitored at daily intervals for 5 days.
The peak production of the enzymes occurred within 3 days of incubation. Among solid supports used in the study, wheat bran
was the best solid matrix followed by groundnut fodder in production of cellulolytic enzymes in solid state fermentation.
Groundnut fodder supported significant production of FPase (2.09 FPU/g), CMCase (1.36 U/g) and -glucosidase activity (0.0117
U/g) in solid state fermentation. Considerable secretion of protein (5.10 mg/g) on groundnut fodder at peak time interval
1st day of incubation was recorded. 相似文献
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Eva Söderling 《Preparative biochemistry & biotechnology》2013,43(2):191-203
A homogenous, chloride-dependent arginine amino-peptidase was purified from the liver of human fetuses by gel-permeation chromatography followed by subsequent fractionation on DEAE-Sepharose CL-6B and affinity chromatography on Sepharose 4B covalently coupled to L-arginine. The purified enzyme showed a single band on disc-gel electrophoresis. In SDS-gel electrophoresis the molecular weight of the enzyme was found to be 92′000 ± 2000. N-L-Arginyl-2-naphthylamine and N-L-lysyl-2-naphthylamine were practically the only amino-acyl-2-naphthylamines hydrolyzed by the enzyme. The method was successfully applied for the purification of the chloride-dependent arginine aminopeptidases from human erythrocytes, serum, synovial fluid and rat inflammatory exudates. 相似文献
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In the present work, stable fluidization of sawdust was achieved in a bench fluidized bed with an inclined orifice distributor without inert bed materials. A solids circulation pattern was established in the bed without the presence of slugging and channeling. The effects of treatment severity and weight loss on the solid product properties were identified. The decomposition of hemicelluloses was found to be responsible for the significant changes of chemical, physical and mechanical properties of the torrefied sawdust, including energy content, particle size distribution and moisture absorption capacity. The hydrophobicity of the torrefied sawdust was improved over the raw sawdust with a reduction of around 40 wt.% in saturated water uptake rate, and enhanced with increasing the treatment severity due to the decomposition of hemicelluloses which are rich in hydroxyl groups. The results in this study provided the basis for torrefaction in fluidized bed reactors. 相似文献
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Modeling, simulation, and experimental validation for continuous Cr(VI) removal from aqueous solutions using sawdust as an adsorbent 总被引:1,自引:0,他引:1
Continuous adsorption experiments were performed in a fixed-bed adsorption column to evaluate the performance of low-cost adsorbent (sawdust) developed for the removal of Cr(VI) from aqueous solutions. The effects of influencing parameters such as flow rate, mass of adsorbent, initial Cr(VI) concentration were studied and the corresponding breakthrough curves were obtained. The fixed-bed adsorption process parameters such as breakthrough time, total percentage removal of Cr(VI), adsorption exhaustion rate and fraction of unused bed-length were obtained. A mathematical model for fixed-bed adsorption column was proposed by incorporating the effect of velocity variation along the bed-length in the existing model. Pore and solid diffusion models were used to describe the intra-particle mechanism for Cr(VI) adsorption. The proposed mathematical model was validated with the literature data and the experimental data obtained in the present study and the model was found to be good for explaining the behavior of breakthrough curves. 相似文献
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Summary Sawdust fromCanarium schweinfurthii (Engl.), a common source of timber in the rainforest zone of Nigeria was subjected to various treatments to improve the nutrient content and aid the decomposition of the otherwise highly-lignified material. The treatments were then either incorporated into the soil or added to the soil surface as a mulch in both greenhouse and field studies. The greenhouse studies involved two six-week sowings in the same soil while the field study involved 3 season sowings (2 rainly, one dry season) using maize (Zea mays L.var. Western yellow) as a test crop.Results indicated that in the greenhouse, incorporation of untreated sawdust led to significant reductions in maize growth, dry matter yield and uptake of N and other nutrients. While the incorporated inorganically amended sawdust treatment produced significantly higher dry matter yield, that produced by the surface-applied organically amended treatment was significantly higher than the incorporated treatment. Except for untreated sawdust, the incorporation of organically and inorganically amended sawdust increased the contents insoil of N, available P, and exchangeable K. 相似文献
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Kim YJ Choi WJ Lim SS Kwak JH Chang SX Kim HY Yoon KS Ro HM 《Bioresource technology》2008,99(13):5452-5458
Temporal changes in delta(15)N of cattle feedlot manure during its composting with either rice hull (RHM) or sawdust (SDM) as bedding materials were investigated. Regardless of the bedding material used, the delta(15)N of total N in the manure increased sharply from +7.6 per thousand to +9.9 per thousand and from +11.4 per thousand to +14.3 per thousand, respectively, in RHM or SDM, within 10 days from the commencement of composting. Such increases could be attributed primarily to N loss via NH(3) volatilization and denitrification based on the very high delta(15)N values (greater than +20 per thousand) of NH(4)(+) and NO(3)(-) in the co-composted manure. The delta(15)N of total N in RHM was substantially lower (by more than 3 per thousand) than that in SDM, suggesting that the delta(15)N of the composted manure was affected not only by N loss but also by the type of bedding material used. Specifically, the higher N concentration in the rice hull than in the saw dust could lead to a greater (15)N isotope dilution. 相似文献
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Carbonaceous adsorbents based on sawdust pellets from coniferous tree species were obtained by carbonisation at different temperatures and different periods of time. The effect of NO2 adsorption in dry and wet condition on the sorption ability of the chars obtained was tested. The results have shown that NO2 sorption properties of chars depend on the conditions of pyrolysis and the conditions of adsorption. The best NO2 sorption capacity of 18.3 and 43.1 mg/g in dry and wet conditions, respectively, was noted for the char sample pyrolysed at 800 °C for 60 min. The FTIR spectra of the exhausted samples reveal a great increase in the intensity of the band at 1380 cm−1 assigned to the vibrations of –NO2, –ONO2 or , while in the DTG curves a new peak appears in the range 200–400 °C assigned to the release of nitrogen compounds of low stability in high temperatures. 相似文献
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