Reduction Of Hemicellulose Content Research Articles

Effect of Benzoyl Chloride and Fiber Loading on Mechanical Properties and Biodegradation of Poly Lactic Acid/Sugarcane Bagasse Fibre Composites

This study aimed to investigate the properties of benzoyl chloride modified and unmodified poly lactic acid and sugarcane bagasse fibre composites (PLA/SCBF), as well as the impact of chemical treatment on the mechanical and biodegradation properties of these composites. In this study, Fourier Transform Infrared (FTIR) Spectroscopy was employed to examine the benzoyl chloride modified and unmodified fibre samples. Additionally, Scanning Electron Microscope (SEM) and Thermal Gravimetric Analysis (TGA) techniques were utilised to investigate the morphology and thermal behaviour of the Poly lactic/SCBF composites. The results indicate that the use of benzoyl chloride treatment resulted in an increase in the tensile, flexural characteristics, impact strength, and hardness strength. The treatment with benzoyl chloride resulted in a reduction in both water absorption and biodegradability. The research also elucidated the impact of increasing the quantity of sugar cane bagasse on the aforementioned qualities. The addition of SCBF at higher loading resulted in a decrease in the tensile strength, biodegradability, flexural strength, and impact strength. The water absorption and hardness exhibited a positive correlation with the increase in fibre loading. The observed improvement in mechanical characteristics indicates that the treatment effectively enhanced the interfacial adhesion between SCBF and the PLA matrix. The enhancement of the interfacial adhesive forces was observed by the examination of scanning electron microscopy (SEM) micrographs. The Fourier Transform Infrared (FTIR) spectrum of the treated solvent-cast bamboo fibre (SCBF) exhibited the presence of a benzoyl group attached to the fibre, indicating successful benzoyl chloride treatment. Additionally, a modest reduction in hemicellulose content was seen following the treatment. The thermal characteristics of the modified PLA/SCBF composites were found to be enhanced based on the results obtained from the TGA-DTA analysis.

Kinetin-mediated reduction of cadmium accumulation in rice (Oryza sativa L.) via modulation of cell wall binding capacity in a NO-dependent manner

Cadmium (Cd) is a heavy metal that is toxic to both plant growth and human health. Kinetin, a precursor of cytokinin, plays crucial roles in the response of plants to abiotic stress. However, the mechanism underlying kinetin detoxification in Cd-induced stress remains poorly understood. In this study, we observed a significant increase in endogenous kinetin levels in both rice shoots and roots under Cd stress. Furthermore, the application of exogenous kinetin resulted in a reduction in hemicellulose content within cell walls, thereby reducing the cell wall's capacity to bind Cd and limit its entry into cells. In addition, exogenous kinetin downregulated the transcript levels of genes associated with Cd uptake and root-to-shoot translocation while simultaneously upregulating the transcript levels of genes involved in Cd efflux from cells and sequestration into vacuoles, consequently leading to reduced Cd accumulation in rice plants. Moreover, kinetin significantly decreased nitric oxide (NO) accumulation in response to Cd stress, potentially facilitating detoxification during Cd-induced stress through a NO-dependent mechanism. Overall, our findings suggest that kinetin enhances rice's tolerance to Cd by increasing the cell wall's ability to bind Cd and regulating gene expression related to Cd accumulation. These mechanisms may be NO-dependent and could potentially inform the development of new strategies for mitigating Cd toxicity in agricultural systems.

Thermochemical modification of beech wood with ammonium hydroxide

Four variants of the thermochemical modification were conducted on beech wood at a temperature of 130 °C, employing NH4OH concentrations of 5% or 10% for durations of either 12 or 24 h. The weight% gain (WPG) and bulking coefficient (BC) were initially calculated. Subsequently, the wood’s degree of discoloration was assessed using the CIELAB-colour-system. Chemical structure alterations were determined through Fourier transform infrared spectroscopy (FTIR), while the compressive strength of the wood parallel to the grain was measured. As the NH4OH concentration increased and the treatment duration extended, the samples displayed simultaneous weight increase and volume reduction. The ΔE* values of the samples ranged from 19.33 to 21.09 units, indicating significant color alteration. FTIR analysis revealed differences between the spectra of the unmodified control sample and the NH4OH-treated samples. The modification reduced in hydroxyl and carboxyl groups within the main and side chains of hemicelluloses. Additionally, a decrease in the absorption peak intensity of the unconjugated carbonyl group at 1740 cm− 1 indicated a relative reduction in hemicellulose content. Compressive strength tests showed that the thermochemical modification improved the modulus of elasticity, increasing it from 10,898 MPa (in the control sample) to a range of 11,663 − 13,390 MPa. Similarly, the compressive strength increased from 77.10 MPa to 81.56-107.19 MPa. Interestingly, this improvement was more pronounced with higher concentrations of NH4OH and prolonged modification durations.

Effect of hemicellulose content on the solution properties of cellulose carbamates in NaOH/ZnO aqueous system

Hemicellulose removal from bleached bamboo pulp is key to produce qualified dissolving pulps. In this work, alkali/urea aqueous solution was firstly applied to remove hemicellulose in bleached bamboo pulp (BP). The effect of urea usage, time and temperature on the hemicellulose content of BP was studied. The reduction of hemicellulose content from 15.9 to 5.7 % was achieved in 6 wt% NaOH/1 wt% urea aqueous solution at 40 °C for 30 min. Cellulose carbamates (CCs) were obtained from the esterification of BP with urea. The dissolution behavior of CCs in NaOH/ZnO aqueous solutions with different degree of polymerization (DP), hemicellulose and nitrogen contents were studied by using optical microscope and rheology. The highest solubility was up to 97.7 % when the hemicellulose was 5.7 % and Mη was 6.5 × 104 (g/mol). With the decrease of hemicellulose content from 15.9 % to 8.60 % and 5.70 %, the gel temperature increased from 59.0, 69.0 to 73.4 °C. The apparent gelation time increased from 5640 to 12,120 s with the hemicellulose content increased from 8.60 % to 15.9 %. CC solution with 5.70 % hemicellulose always keeps a liquid-state (G" > G') until the test time reached 17,000 s. The results showed that the removal of hemicellulose, the decrease of DP and the increase of esterification endowed CC with higher solubility and solution stability.

Structural alteration of cocoa bean shell fibers through biological treatment using Penicillium roqueforti

Lignocellulosic residues, such as cocoa bean shell (FI), are generated in large quantities during agro-industrial activities. Proper management of residual biomass through solid state fermentation (SSF) can be effective in obtaining value-added products. The hypothesis of the present work is that the bioprocess promoted by P. roqueforti can lead to structural changes in the fibers of the fermented cocoa bean shell (FF) that confer characteristics of industrial interest. To unveil such changes, the techniques of FTIR, SEM, XRD, TGA/TG were used. After SSF, an increase of 36.6% in the crystallinity index was observed, reflecting the reduction of amorphous components such as lignin in the FI residue. Furthermore, an increase in porosity was observed through the reduction of the 2θ angle, which gives the FF a potential candidate for applications of porous products. The FTIR results confirm the reduction in hemicellulose content after SSF. The thermal and thermogravimetric tests showed an increase in the hydrophilicity and thermal stability of FF (15% decomposition) in relation to the by-product FI (40% decomposition). These data provided important information regarding changes in the crystallinity of the residue, existing functional groups and changes in degradation temperatures.

High-pressure CO2 hydrothermal pretreatment of peanut shells for enzymatic hydrolysis conversion into glucose

Peanut shells (i.e., an abundant industrial by-product) were subjected to an innovative hydrothermal pretreatment approach using high-pressure CO2 to enhance their enzymatic hydrolysis conversion into glucose. This pretreatment led to a reduction in hemicellulose content in the pretreated peanut shells from 12.4% to as low as 1.8%, which facilitated subsequent conversion into glucose by enzymatic hydrolysis. This pretreatment approach was assessed within a 170–200 °C temperature range and a 20–60 bar CO2 pressure range, after which the results of these conditions were compared to those of conventional hot water pretreatment. Treatment at 190 °C and a 60-bar CO2 pressure was determined to be optimal, resulting in the highest glucose yield (80.7%) from subsequent enzymatic hydrolysis. Acidic conditions resulting from CO2-derived carbonic acid significantly reduced the hemicellulose content of the peanut shells and weakened the interaction between cellulose, hemicellulose, and lignin, improving enzyme accessibility to the cellulose. Furthermore, high-pressure CO2 increased the pore size and porosity of the resulting pretreated peanut shells, improving their enzyme adsorption capacities, as confirmed by cellulase adsorption and mercury intrusion porosimetry tests. The dual effect from high-pressure CO2 led to significant hemicellulose reduction and improved adsorption of enzymes on the cellulose, which in turn increased glucose yield from the subsequent enzymatic hydrolysis of pretreated peanut shells. Alcoholic fermentation of the hydrolyzed glucose resulted in a 12.4% increase in bio-ethanol production compared to a glucose control, thus highlighting the potential of pre-treated peanut shells as a glucose precursor used in biofuel industry.

Enhanced microfibrillated cellulose-based film by controlling the hemicellulose content and MFC rheology

Understanding of how hemicellulose acts on the rheology of microfibrillated cellulose in suspension or after drying is insufficient. In this study, different concentrations of hemicellulose in the cellulose pulp of Eucalyptus sp. were obtained by alkaline treatment with potassium hydroxide. The treated pulps and the suspension of microfibrils obtained were characterized by thermogravimetric analysis, zeta potential, scanning electron microscopy, rheological analysis, X-ray diffraction and dynamic mechanical analysis. The lowest hemicellulose content obtained was approximately 2% wt. Treatments with KOH above 10% did not cause a significant reduction in hemicellulose content and caused a change in the type of cellulose crystallinity. The rheological analysis showed that the apparent viscosity of the suspensions was strongly influenced by the presence of hemicellulose. The morphology of the MFC films of the treated pulps presented the appearance of voids with the reduction of hemicellulose content, generating a decrease in its mechanical properties.

English

The aim of this study was to evaluate the alkaline hydrolysis of chemical composition of sugarcane bagasse from urban centers. The experimental design was completely randomized design in split plots (5×4), composed of five application levels (0, 1, 2, 3 and 4%) and four NaOH exposure periods (24, 48, 72 and 96 h) in four replicates. Dry matter, ash, neutral detergent fiber, acid detergent fiber, cellulose and lignin were analyzed. The application of 4% of NaOH promoted reduction of neutral detergent fiber (NDF) and acid detergent fiber (ADF). There was no significant difference (p> 0.05) in treatments with application of 3 and 4% of NaOH; the treatment promoted a higher reduction in hemicellulose content. There was linear effect of the level of NaOH on dry matter, ash, NDF, ADF, and hemicellulose, however, lignin and cellulose content presented quadratic effect. Alkaline hydrolysis with NaOH provided improvements in the chemical composition of the sugarcane bagasse, which allows it to be used as feed for ruminants raised in urban and peri-urban environments. Key words: Chemical treatment, industrial waste, ruminant.

Designing Cell Walls for Improved Bioenergy Production

Dwindling supply and unpredictable price fluctuations of fossil fuels have necessitated a renewed worldwide search for alternative fuels. Plant cell walls, rich in cellulose and hemicellulose, are actively pursued for their use in production of second-generation biofuels. It has been envisioned that degradation of these carbohydrate polymers to their sugar monomer subunits (saccharification) will provide necessary substrates for their yeast-mediated fermentation to ethanol. But the major component of plant cell walls, cellulose, is not easily amenable to this type of deconstruction and is tightly interlinked with hemicelluloses and lignin, making cell walls highly recalcitrant to saccharification.

Effect of superficial air velocity on solid state fermentation of palm kernel cake in a lab scale fermenter using locally isolated fungal strain

Solid state fermentation (SSF) is emerging as an attractive alternative to submerged fermentation despite the engineering problems such as removal of metabolic heat, transport of oxygen and moisture into the particles and the heterogeneity of the substrate. In the present work, a lab scale fermenter which can be operated as fluidized bed and packed bed was fabricated. Solid state fermentation of palm kernel cake (PKC) using fungal strain TW1 was carried out at three superficial air velocities. PKC particles of mean diameter 855 μm were used and the fluidizing medium was air. Reducing sugar concentration, biomass growth, bed moisture content, substrate pH, and hemicellulose content were measured. The maximum increase in reducing sugar concentration was at 0.17 m/s since an increase in mannose from 14.55 to 18.63 mg mannose/g dry PKC was observed. The hemicellulose content of this fermented PKC was estimated and the result was around 10% in reduction of hemicellulose content in fermented PKC. Further improvement of PKC bioconversion can likely be achieved by selection of a more robust microbe that can withstand the conditions in the fluidized bed during SSF and by creating a system which can maintain the moisture content of PKC during SSF of PKC throughout the packed bed.