BACKGROUND Obtaining a better understanding of the complex mechanisms occurring during lignocellulosic deconstruction is critical to the continued growth of renewable biofuel production. A key step in bioethanol production is thermochemical pretreatment to reduce plant cell wall recalcitrance for downstream processes. Previous studies of dilute acid pretreatment (DAP) have shown significant cha...

The present study explores the mechanism of cellulose biosynthesis in Gluconoacetobacter hansenii. The cellulose synthase enzyme was purified as membrane fraction and solubilized by treatment with 0.1% digitonin. The enzyme was separated by native-gel electrophoresis and β -D-glucan analysis was carried out using in vitro gel assay. The cellulose synthase has glycoprotein nature and composed tw...

this research was performed to study the effect of murray red gum tree age (4, 6, 8 years) on the chemical components, viscosity and the cellulose degree of polymerization. the eucalyptus trees were cut at the ages of 4, 6, and 8 from hand planted forests. the contents of cellulose, hemicellulose, lignin, extractives and ash for each age were then determined. the results show that with increasi...

the effect of bleaching with sodium hypochlorite, as one of the most important parameters in obtaining optimal alpha cellulose pulp from cotton linter was studied. in this respect, unbleached cotton linter pulp was prepared from parchin chemical industry co., bleached by hea sequence in ph=9, 11 and 13; and then its chemical structures properties such as alpha cellulose, degree of polymerizatio...

Fundamental features of microbial cellulose utilization are examined at successively higher levels of aggregation encompassing the structure and composition of cellulosic biomass, taxonomic diversity, cellulase enzyme systems, molecular biology of cellulase enzymes, physiology of cellulolytic microorganisms, ecological aspects of cellulase-degrading communities, and rate-limiting factors in nat...

Slurries of rice-straw cellulose (obtained by delignification and removal of hemicelluloses from the powdered raw material) were subjected to ultrasonic waves at different intensities for various times (constant temperature). Susceptibility of the samples to cellulose-hydrolysis increased initially with pretreatment time, reaching a maximum or a constant level thereafter. Maximum glucose yi...

The ruminal cellulolytic bacterium Ruminococcus flavefaciens FD-1 was grown in cellulose-fed continuous culture with 20 different combinations of pH and dilution rate (D); the combinations were selected according to the physiological pH range of the organism (6.0 to 7.1) and growth rate of the organism on cellulose (0.017 to 0.10 h-1). A response surface analysis was used to characterize the ef...

Water-cast films of two ethers of cellulose, hydroxypropylcellulose (HPC) and hydroxyethylcellulose (HEC), with dispersed silica particles, were deposited on flat substrates. X-ray specular reflectivity was used to characterize the structure of these solid ca. 1000 Å thick films as a function of the added colloidal fraction. It was shown that the structural changes resulting from increasing amo...

Haematological and biochemical aspects of a new family with heterozygous Hb O Padova [alpha 30(B11) Glu----Lys] is described. This variant has been found on a screening programme of abnormal haemoglobin in cord blood. It was separated by cellulose acetate, isoelectric focusing, citrate agar, DEAE-cellulose chromatography and by cation exchange high-performance liquid chromatography. The heat st...

Cellulose is usually isolated from the other components of plant material for analysis of carbon stable isotope ratios (dC). However, many studies have shown a strong correlation between whole-wood and cellulose dC values, prompting debate about the necessity of cellulose extraction for tree-ring studies. The dC values were measured in whole wood, extractive-free wood, purified cellulose, aceto...