Bamboo Hemicelluloses Research Articles

Preparation of Bamboo Hemicellulose Hydrolysate Possessing Anti-oxidative Properties and Their Effects on Mice Plasma Cholesterol

Preparation of Bamboo Hemicellulose Hydrolysate Possessing Anti-oxidative Properties and Their Effects on Mice Plasma Cholesterol

Regulating effect of hemicelluloses on the preparation and properties of composite Lyocell fibers

Composite Lyocell fibers were successfully prepared from cotton linter pulp and bamboo hemicelluloses with N-methyl-morpholine-N-oxide as a solvent. The viscosity of the spinning solutions, as well as the structural and mechanical properties of the composite fibers were investigated to understand the effect of hemicelluloses on the dissolution process and the properties of fibers. The addition of hemicelluloses raised the concentration of spinning dopes and reduced the average molecular weight of raw materials, leading to the increase and then decrease of the viscosity of solution. The crystal and morphological structure of the fibers were slightly influenced by the presence of hemicelluloses, while the tensile strength and modulus of the fibers were improved by adding appropriate amount of hemicelluloses. Moreover, the distribution of hemicelluloses in the solution and composite fiber were proposed to illustrate this regulating effect. This study provided an alternate way to improve the properties of Lyocell fibers and enlarge the utilization of hemicelluloses.

Improved Cellulose Yield in the Production of Dissolving Pulp from Bamboo Using Acetic Acid in Prehydrolysis

Despite increasing demand for dissolving pulps from raw material, production costs remain quite high compared to regular paper pulp. Research literature to date has focused on improving performance and quality but has not simultaneously explored how to improve yield, which typically falls below 35%. Dissolving pulp from bamboo, as a widely available, high-quality raw material, was investigated with dilute acetic acid pre-hydrolysis before cooking and cold caustic extraction prior to bleaching. It was found that dilute acetic acid in the pre-hydrolysis stage could speed up the degradation of hemicellulose in bamboo and improve the diffusion of the cooking liquor in bamboo fiber compared with hot-water treatment. The dissolving pulp from bamboo was produced with 93% α-cellulose, 90% ISO brightness, 959 mL/g viscosity, 5.23% xylans, and 0.17% ash. The overall yield on the basis of raw material was 37%, which was higher than other documented processes using other agents in pre-hydrolysis.

Microbial conversion of bamboo hemicellulose hydrolysate to xylitol

A hemicellulose hydrolysate containing 19 g L−1 xylose was prepared from the culm of bamboo (Phyllostachys pubescens) by hydrolysis with 3 % sulphuric acid with a liquor to solid ratio of 10 (g g−1) at 121 °C for 1 h. After detoxification of the hydrolysate with a commercially available activated char followed by neutralisation with calcium carbonate, the resulting sugar solution was subjected to fermentation using the yeast, Candida magnoliae. The maximum xylitol production (10.5 g L−1) and the maximum xylitol volumetric productivity (0.42 g L−1 h−1) were attained under agitation set at 400 min−1 and aeration rate of 0.67 vvm (volume of air per volume of medium per minute). According to the results, a suitable control of the oxygen supply permits the xylitol formation from bamboo hemicellulose hydrolysate.

Green, microwave-assisted synthesis of silver nanoparticles using bamboo hemicelluloses and glucose in an aqueous medium

A green, straightforward, microwave-assisted method of synthesizing silver nanoparticles in an aqueous medium was developed using bamboo hemicelluloses as stabilizer and glucose as reducer. The effects of irradiation time as well as initial concentrations of hemicelluloses, glucose, and AgNO3 on the silver nanoparticle formation were studied. The silver nanoparticles were characterized by UV–vis spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results indicated the formation of spherical, nanometer-sized particles. The reaction parameters significantly affected the formation rate, size and distribution of the silver nanoparticles. The average particle size was 8.3–14.8nm based on TEM analysis. XRD analysis revealed that the particles calcined at 300°C were face-centered cubic. XPS characterization showed that silver Ag(0) coexisted with silver Ag(I). The synthesis process of silver nanoparticles was rapid and eco-friendly.

Structural Characterization of Hemicellulosic Polysaccharides Isolated from Bamboo (Phyllostachys pubescens Mazel)

In the present work water soluble hemicellulosic polysaccharides HPW, 2% NaOH soluble hemicelluloses HPl and HPlll, and 5% KOH soluble fractions HPll and HPlV, were classically separated from bamboo (Phyllostachys pubescens Mazel) aged one year. In addition to sugar composition analysis, the hemicelluloses were also elucidated by GPC, FTIR, NMR and AFM techniques. Xylose (33.70-74.09%) and arabinose (25.03-59.04%) were the main neutral sugar, with ratios of arabinose to xylose being between 0.34 and 1.70. GPC measurement showed that the fractions HPW, HPlll and HPlV precipitated in ethanol presented much broader molecular weight distribution. FTIR and NMR analysis suggested that the bamboo hemicelluloses could be mainly defined as arabinoxylans substituted by (1→2)-linked 4-O-methyl-α-D-glucuronic aid and acetyl group as side chains. AFM images of HPlll revealed a distribution of both island and rod aggregations when 0.01 mg/mL sample in 0.1 M NH4Ac solution was deposited onto freshly cleared mica and air dried.

Synthesis of Silver Nanoparticles by Using Bamboo Hemicellulose as Template in Aqueous Solution

Hemicellulose was separated from bamboo using alkaline method. Silver nanomaterials had been prepared using the hemicellulose as template and silver nitrate as precursor via a green approach. The synthesized samples were characterized by UV-vis, XRD, and SEM techniques. UV-visible spectrum and XRD diffraction pattern revealed that the silver ion (Ag+) had been reduced to the metallic silver nanoparticles (Ag0). The results demonstrated that after calcination at 500 °C in air atmosphere, nano Ag/C compound was obtained. The hemicellulose acted as an effective nanoreactor for the in situ synthesis of silver nanoparticles. This novel procedure provides a facile and environmental way to manufacture silver nanoparticles for various applications.

Isolation and structural characterization of hemicelluloses from the bamboo species Phyllostachys incarnata Wen

Water and alkali-soluble polysaccharides, isolated by sequential extractions with distilled water, 0.5% and 1% NaOH, 60% ethanol containing 1% NaOH, and 3%, 5% and 8% NaOH, were prepared at 60°C for 3h from dewaxed bamboo Phyllostachys incarnata Wen. The yields of the seven fractions together accounted for 80.1% of total available hemicellulosic polysaccharides. Sugar composition studies showed that the water-soluble polysaccharides consisted mainly of glucose units, while xylose, arabinose and glucuronic acid were the major sugars in alkali-soluble hemicelluloses. Moreover, the molecular weights of these polymers varied between 3760 and 36,000g/mol as revealed by GPC. Furthermore, the structure of the hemicellulosic fraction extracted with 3% NaOH was determined by 1H and 13C NMR spectroscopy along with 2D HSQC. It was found that the bamboo hemicelluloses were O-acetyl-(4-O-methylglucurono)-arabinoxylans, and the structural element could be identified as below: 1,4-β-D-[2-O-Ac][2,3-di-O-Ac][4-O-Me-α-D-GlcpA-(1→2)][α-L-Araf-(1→2)(1→3)]-xylp.

Studies on the Starch and Hemicelluloses Fractionated by Graded Ethanol Precipitation from Bamboo Phyllostachys bambusoides f. shouzhu Yi

Starch from bamboo Phyllostachys bambusoides f. shouzhu Yi evaluated by means of solid-state 13C CP/MAS NMR and X-ray diffraction showed a typical B-type pattern with a very low degree of crystallinity (10.9%). In addition to starch, alkali-soluble hemicelluloses were further fractionated by graded precipitation at ethanol concentrations of 0 (HA), 15, 30, 45, 60, and 75% (v/v). Chemical composition and structural features of the six hemicellulosic subfractions were investigated by a combination of sugar analysis, GPC, FT-IR, GC-MS, 1D (1H and 13C) and 2D (HSQC) NMR spectra, and thermal analysis. The results showed that the bamboo hemicelluloses were O-acetylated 4-O-methyl-glucuronoarabinoxylans (GAX) consisting of a linear (1→4)-β-D-xylopyranosyl backbone decorated with branches at O-3 of α-L-arabinofuranosyl (5-12 mol%) or at O-2 of 4-O-methylglucuronic acid units and acetyl groups (0.8-11 mol%). The molecular weights of these polysaccharides ranged between 13400 and 67500 g/mol, and the molar ratios of A/X and G/X increased with ascending ethanol concentrations. Moreover, xylo-oligosaccharides (XOS) with DP 1-6 were produced by enzymatic hydrolysis of hemicelluloses and the total yields of XOS were range of 21.5 to 40.6%. The structure-property relationships were also established in order to improve enzyme accessibility.

Hemicellulose decomposition and saccharides production from various plant biomass by sulfonated allophane catalyst

Typical biomass in Japan (bamboo, Japanese cedar and rice straw) were decomposed by using sulfonated allophane catalyst and hemicellulose in bamboo was preferentially decomposed to xylose. The maximum xylose yield was 40.9% (on the base of hemicellulose) in the reaction at 150 °C for 4.0 h. Mannose and xylose were mainly produced from Japanese cedar and arabinose was mainly produced from rice straw.

Selective Production of Xylose and Xylo-oligosaccharides from Bamboo Biomass by Sulfonated Allophane Solid Acid Catalyst

Abstract Bamboo biomass was hydrolyzed by using sulfonated allophane catalyst and hemicellulose in bamboo was preferentially decomposed to xylose and xylo-oligosaccharides in the range from 130 to 160 °C.

Carbonization mechanism of bamboo (phyllostachys) by means of Fourier Transform Infrared and elemental analysis

Bamboo was carbonized at different temperatures ranging from 200°C to 600°C. The dependence of the change of hemicellulose, cellulose, and lignin on the temperature was investigated by means of elemental analysis and Fourier Transform Infrared (FTIR) spectra of the residual solid products. The results showed (1) Below 200°C, hemicellulose in bamboo was decomposed and a large amount of hydroxyl groups are dislocated from hemicellulose and cellulose, accompanied by the evolution of water to escape (2) 200°C–250°C, cellulose in bamboo was drastically decomposed whereas the net structure of lignin keep stable, with the except of the dislocation of methoxyl groups from lignin. (3) 250°C–400°C, the net structure of lignin collapse, up to 400°C, followed by that the more position in aryl groups are substituted. (4) For bamboo carbonization, the aromatization of residual carbon has approximately completed at the temperature as high as 600°C. But the fusion of aromatic rings possibly does not occur.