Changes of Chemical Composition and Hemicelluloses Structure in Differently Aged Bamboo ( Neosinocalamus affinis) Culms

Structure analysis and immunomodulatory activity of novel oligosaccharide from Nicotiana tabacum roots

A novel oligosaccharide (NTRP60-W-2) with an average molecular weight of 1377 Da was isolated and purified from Nicotiana tabacum roots. Its structural characteristics and immunomodulatory properties were investigated. Structural analysis revealed that NTRP60-W-2 was composed exclusively of glucose, featuring →1)-α-D-Glcp-(6→ backbone. Immunological assays demonstrated that NTRP60-W-2 significantly enhanced cell viability, nitric oxide production and cytokine secretion (IL-6 and TNF-α) in RAW264.7 cells. These findings provide a foundation for further exploration of Nicotiana tabacum carbohydrates and their potential biological activities.

Understanding the dynamic evolution of hemicellulose during Pinus taeda L. growth

Pinus taeda L. is a fast-growing softwood with significant commercial value. Understanding structural changes in hemicellulose during growth is essential to understanding the biosynthesis processes occurring in the cell walls of this tree. In this study, alkaline extraction is applied to isolate hemicellulose from Pinus taeda L. stem segments of different ages (1, 2, 3, and 4 years old). The results show that the extracted hemicellulose is mainly comprised of O-acetylgalactoglucomannan (GGM) and 4-O-methylglucuronoarabinoxylan (GAX), with the molecular weights and ratios (i.e., GGM:GAX) of GGM and GAX increasing alongside Pinus taeda L. age. Mature Pinus taeda L. hemicellulose is mainly composed of GGM, and the ratio of (mannose:glucose) in the GGM main chain gradually increases from 2.45 to 3.60 with growth, while the galactose substitution of GGM decreases gradually from 21.36% to 14.65%. The acetylation of GGM gradually increases from 0.33 to 0.45 with the acetyl groups mainly substituting into the O-3 position in the mannan. Furthermore, the contents of arabinose and glucuronic acid in GAX gradually decrease with growth. This study can provide useful information to the research in genetic breeding and high-value utilization of Pinus taeda L.

Comprehensive characterization of hemicelluloses obtained from Gleditsia sinensis Lam. pods and the application of moderately degraded hemicelluloses in galactomannan film

The Gleditsia sinensis Lam. pods (GSP) are consistently discarded as waste after saponin extraction due to a lack of industrial or high-value utilization. Herein, the hemicelluloses were extracted from two varieties of GSP and subjected to comprehensive characterization. The molar mass of DMSO-soluble hemicelluloses (53.3-66.0 kDa) was higher compared to that of alkali-soluble ones (24.9-32.6 kDa). The presence of minimal acetyl substitution (3.85-4.49 %) on xylan was unequivocally confirmed. NMR spectroscopic analysis indicated that the hemicelluloses in GSP predominantly consist of a 1,4-β-ᴅ-Xyl backbone with arabinose substituents at O-3 and 4-O-methyl-α-ᴅ-GlcA substituents at O-2 of the xylose residues. p-Coumaric acid substitution also occurred on the 1,4-β-ᴅ-Xyl backbone. Hydrothermal treatment significantly reduced the hemicelluloses' relative molar mass and produced 7-10 % xylo-oligosaccharides. Furthermore, the moderately degraded hemicelluloses exhibited significantly enhanced biological activity. Finally, the incorporation of the moderately degraded hemicelluloses imparted the galactomannan film with exceptional antioxidant properties (81.1 % DPPH scavenging activity), while negligibly affecting its transparency. Our study's findings will contribute to a comprehensive understanding of the structural and biochemical properties of hemicellulose in waste G. sinensis pods, thereby facilitating their enhanced utilization in industrial applications.

Characterization of hemicellulose in Cunninghamia lanceolata stem during xylogenesis

In this study, hemicellulose was isolated from the apical, middle and basal segments of C. lanceolata stem to investigate the dynamic change of its structure during xylogenesis. Results showed that the C. lanceolata hemicellulose is mainly consisted of O-acetylgalactoglucomannan (GGM) which backbone is alternately linked by β-d-mannopyranosyl (Manp) and β-d-glucopyranosyl (Glcp) via (1 → 4)-glycosidic bond, while the side chains are α-d-galactopyranosyl (Galp) and acetyl. In addition, 4-O-methylglucuronoarabinoxylan (GAX) is another dominant structure of C. lanceolata hemicellulose which contains a linear backbone of (1 → 4)-β-d-xylopyranosyl (Xylp) and side chains of 4-O-Me-α-d-glucuronic acid (MeGlcpA) and α-L-arabinofuranose (Araf). The thickness of the cell wall, the ratio of GGM/GAX and the molecular weight of hemicellulose were increased as the extension of growth time. The degree of glycosyl substitutions of xylan and mannan was decreased from 10.34 % (apical) to 8.38 % (basal) and from 15.63 % (apical) to 10.49 % (basal), respectively. However, the total degree of acetylation was enhanced from 0.28 (apical) to 0.37 (basal). Transcriptome analysis showed that genes (CSLA9, IRX9H1, IRX10L, IRX15L, GMGT1, TBL19, TBL25, GUX2, GUX3, GXM1, F8H1 and F8H2) related to hemicellulose biosynthesis are mainly expressed in mature part. This study is of great significance for genetic breeding and high-value utilization of C. lanceolata.

Structural variation of lignin-carbohydrate complexes (LCC) in Chinese quince (Chaenomeles sinensis) fruit as it ripens

Chinese quince (Chaenomeles sinensis) fruits are rich in lignin, and too sour, astringent and woody to be eaten raw. More than 50 % of lignin in plant cell walls is covalently associated with carbohydrates to form lignin-carbohydrate complexes (LCC). In this study, LCC preparations were extracted from fruits harvested on the 15th day of the month from May-October 2019. A variety of chemical and instrumental analytical approaches were used to characterize the LCC fractions, including HPAEC, TGA, GPC, FT-IR, and 2D HSQC NMR. Antioxidant activities were evaluated by DPPH radical scavenging assays. Results showed that the LCC fractions from October fruits had better thermal stability and homogeneity. NMR results revealed that the lignin-lignin linkages in LCC-AcOH preparations included β-O-4', β-β' and β-5', but β-5' linkages were not present in LCC preparations. And the NMR signals of carbohydrate confirmed the presence of lignin-pectin complexes, which was consistent with sugar analysis. All LCC preparations showed good antioxidant activity, among which Björkman LCC from October fruits showed best. This study will facilitate understanding the chemical bonds of LCC macromolecules in the plant cell wall. More specifically, it provides information critical for specific industrial applications of quince fruits.

Steam explosion of Aucoumea klaineana sapwood: Membrane separation of acetylated hemicelluloses

The fractionation of the aqueous effluent of Aucoumea klaineana Pierre (Okoumé) sapwood steam explosion was examined by a sequential-dilution type membrane diafiltration. The permeate and retentate fractions were characterized by HPLC-SEC, HSQC-NMR, FTIR, UV-visible and HPAE-PAD ion chromatography. Diafiltration with 10 kDa regenerated cellulose membrane has been shown to provide efficient fractionation without fouling. O2 and/or O3 acetylated xylans with a lower proportion of O2 and/or O3 acetylated glucomannans were isolated in the retentate (≈35% w/w and 1.08 w/w% based on initial effluent solid content and on initial dry wood respectively, including 65% w/w in the range 9-22 kDa). The molecular weights of the polysaccharides were significantly higher than those obtained by ethanolic precipitation. The permeate concentrated low molecular mass oligomers (90% w/w < 2.3 kDa, 1.88 w/w% based on initial dry wood) composed of pectic sugars, highly acetylated xylans (DS ≈ 0.9) and relatively high proportion of soluble lignin (≈40% w/w) including Lignin-Carbohydrate Complexes (LCCs).

Hydrothermal pretreatment for the production of oligosaccharides: A review

Oligosaccharides are low-molecular-weight carbohydrates with crucial physical, chemical, and physiological properties, which are increasingly important in the fields of food, pharmaceuticals, cosmetics, and biomedicine. Pretreating biomass in a cost-effective way is a significant challenge for oligosaccharides research. Hydrothermal pretreatment is a potentially eco-friendly technology to obtain oligosaccharides by deconstructing biomass. In this work, we compared the differences between hydrothermal pretreatment and the traditional pretreatment method. The fundamentals and classification of hydrothermal pretreatment, as well as the latest studies on hydrothermal preparation of oligosaccharides, were further reviewed and evaluated to provide a theoretical basis for the production and application of oligosaccharides. Some challenges and future trends to develop green and large-scale hydrothermal pretreatment were proposed for the production of oligosaccharides.

Characterization of Immature Bamboo (Phyllostachys nigra) Component Changes with Its Growth via Heteronuclear Single-Quantum Coherence Nuclear Magnetic Resonance Spectroscopy

A 6.2 m high immature bamboo (Phyllostachys nigra) was divided into seven fractions. The bamboo cell walls and lignin samples from young to old were characterized by ¹H-¹³C correlation heteronuclear single-quantum coherence (HSQC) nuclear magnetic resonance (NMR) spectroscopy both qualitatively and semiquantitatively. Mature bamboo and bamboo shoot samples were used as comparison references. HSQC-NMR analysis proved that cellulose and arabinoxylan have already deposited in bamboo shoot, and cellulose amount increased during growth. Lignin side chain linkage formation started from β-ether (β-O-4), then phenylcoumaran (β-5), and finally resinol (β-β). Ferulic acid and p-coumaric acid (pCA) were formed at the earlier stages in the immature bamboo, and the pCA proportion decreased throughout the lignification process. We propose that the bamboo lignification process is distinct from both woody and other herbaceous plants, where syringyl units deposited at the early stage and polymerized with the β-O-4 linkage. Then guaiacyl units formed gradually, and finally, p-hydroxyphenyl units formed.

Comparison of emulsifying capacity of two hemicelluloses from moso bamboo in soy oil-in-water emulsions

Oil-in-water food emulsions consisting of natural emulsifiers has been an active field of green scientific inquiry. Here, we extract two types of new hemicellulose-based emulsifiers (H_H and H_L) from holocellulose and dewaxed materials of bamboo (Phyllostachys pubescens), as well as compare their emulsifying soy oil ability, respectively. The main content of H_H is arabinoxylan, while the primary composition in H_L is glucan. The emulsifying capacity of these two types of hemicellulose-based emulsifiers are evaluated by droplet size distribution, surface charge and optical microscopy. Since H_L possesses higher lignin and protein residual contents, the resultant emulsion exhibits smaller droplets and higher emulsion stability. In comparison, H_H emulsifier has almost no emulsifying capacity due to the lack of non-polar groups. This study provides insight into the choice of hemicelluloses-based emulsifiers for the formation of stable oil-in-water food emulsions.

Oil-in-water food emulsions consisting of natural emulsifiers has been an active field of green scientific inquiry.

Purification, characterization and anticancer activities of exopolysaccharide produced by Rhodococcus erythropolis HX-2

In the present study, an exopolysaccharide (EPS) producer Rhodococcus erythropolis HX-2 was isolated from Xinjiang oil field, China. The HX-2 EPS (name HPS) production reached 8.957 g/L by RSM in MSM medium. The HPS was purified by ethanol precipitation and fractionation by DEAE-Cellulose and Sepharose column, the yield of HPS was 3.736 g/L. HPS composed by glucose, galactose, fucose, mannose and glucuronic acid. FT-IR spectroscopy indicated the presence of a large amount of hydroxyl groups. NMR spectroscopy indicated the existence of both α and β-configuration for sugar moieties present in HPS. The degradation temperature (255.4 °C) of the HPS was determined by thermogravimetric analysis (TGA). A reticular structure of HPS was observed by SEM and the AFM analysis of the HPS revealed straight chains line. Meanwhile, the WSI and WHC of HPS were 92.15 ± 3.05% and 189.45 ± 5.65%, respectively. Finally, In vitro anticancer activity purified EPS was evaluated on L929 normal cells, A549 cancer cells, SMMC-7721 liver cancer cells and Hela cervical cancer cell. HPS inhibited the growth of cancer cells in a certain concentration without damage to normal cells. These characteristics indicate that its potential application value in food, industry and pharmaceutical application.

Synergistic effects of tung oil and heat treatment on physicochemical properties of bamboo materials

The search for green and sustainable modification method to produce durable bamboo materials remains a challenge in industry. Here, heat treatment in tung oil at 100–200 °C was employed to modify bamboo materials. Oil permeation and distribution in the structure of bamboo samples during heat treatment were explored. The synergistic effects of tung oil and heat treatment on the chemical, physical and mechanical properties of bamboo materials, and their mutual relationships were also investigated in detail. Results showed that the tung oil heat treated bamboo not only had an enhanced hydrophobic property and dimensional stability, improved fungi resistance, but also displayed good mechanical performance. Compared with the untreated sample, the water-saturated swelling reduced from 3.17% to 2.42% for the sample after oil heat treatment at 200 °C, and the contact angles of the sample after oil heat treatment at 200 °C can keep >100° after 300 s in radial direction. Such improvement can be attributed to changes of chemical components, increased crystallinity structure, and the formation of oily films inside or over the bamboo surface. Therefore, tung oil heat treatment can be a highly promising technology for bamboo modification in the industry.