Decomposition Of Holocellulose Research Articles

Pectin decomposition at the early stage of brown-rot decay by Fomitopsis palustris.

The sapwood of Japanese cedar (Cryptomeria japonica D. Don) was decayed by the brown-rot fungus Fomitopsis palustris under bright and dark conditions. Scanning electron microscopy revealed the presence of mycelia inside the wood even after 1 week from the start of fungal exposure. Moreover, holes were observed in the torus after fungal exposure. Ruthenium red staining revealed that the pectin in pits was largely absent for 3 weeks. These events occurred before the mass loss of wood samples was confirmed at the early stage. Moreover, FpPG28A was more highly expressed at the hyphal front on a pectin-containing medium under dark conditions compared with bright conditions. This up-regulation under dark conditions indicated that the pectin decomposition ability was promoted inside the wood where light could not reach. In conclusion, we suggest that the brown-rot fungus completed its hyphal expansion within the wood via pectin decomposition in pits before holocellulose decomposition.

ASSESSMENT OF THE EFFECT OF BIOCHAR ON THE PROCESS OF THERMOLISIS OF BIOMASS OF PLANTS GROWN ON RECLAIMED LANDS

Samples of soil contaminated with heavy metals for pot experiments with annual crops (maize, sweet and sudan sorghum) were taken near the mines "Pavlogradska" and "Blagodatna" in the coal-mining region of Western Donbass. The basis of the reclaimed areas was an 8-10 m thick mine rock (MR) dump, covered with different layers of black soil or red-brown clay by creating two types of soil artificial profiles with the addition of 30 cm of black soil (30 cm of BS +MR) and 50 cm red-brown clay (50 cm RBC + MR). Experimental soil samples were treated with 3.0% (w/w) biochar. The purpose of the study was to study the effect of the addition of biochar on the process of thermal destruction of the biomass of maize, sweet and sudan sorghum, grown on different substrates - components of artificial reclaimed profiles (upper layers of chernozem mass and red-brown clay). The process of thermolysis of biomass components of three agricultural crops was studied by the method of thermogravimetric analysis. Thermal destruction of the biomass of the three studied plant species occurred in two stages: evaporation of water and volatile compounds (stage 1) and decomposition of the main components: hemicellulose, cellulose and lignin (stage 2). The first stage took place in the temperature range of 50-180°С. The process was slow, the maximum speed did not exceed 5-8%/min, the extreme point was observed at a temperature of 100-110°C. Loss of body weight is insignificant, 4.5–7.5%. The second stage is divided into two phases: the decomposition of holocellulose with the beginning of lignin decomposition (phase 1) and the cessation of lignin decomposition, and the formation of non-combustible residue (phase 2). Destruction of holocellulose occurred in the temperature range of 190-390°С. Due to the large amount of hemicellulose in the biomass of the studied plants, its decomposition was shifted to the region of higher temperatures. Therefore, the degradation ranges of hemicellulose and cellulose overlapped, and only one extreme point was observed in the DTG curves. The process proceeded at high speeds with the peak of destruction in the temperature range of 280-310°C. Weight loss was also the most significant and was between 50 and 55%. Decomposition of lignin occurred rather slowly, with one insignificant peak in the temperature range of 420-440°C. A weight loss of 26-30% has been established. At the first stage, the process proceeded mainly with heat absorption; the reactions of the second stage were exothermic with noticeable thermal effects in the zones of cellulose and lignin decomposition. Differences in thermal characteristics of sugar sorghum biomass grown on different substrates and with the addition of biochar were determined in the process of thermolysis. Degradation of holocellulose occurred more slowly in biomass collected from a vessel with red-brown clay, in contrast to lignin, which decomposed faster than in the experiment where the substrate was a loose layer of chernozem. The share of non-combustible residues was almost 2 times smaller. A slight increase in the rate of the cellulose decomposition reaction (1,2 times) and a significant increase in the rate of the lignin destruction reaction (5 times) was observed. In the treatment with biochar, a more complete combustion of biomass was observed. The rate of cellulose decomposition in the experiment with red-brown clay became somewhat higher, although the decomposition of lignin occurred more slowly. The share of non-combustible residues increased by 1,8 times. Thermal destruction of Sudan grass biomass on both substrates occurred in a similar manner. The addition of biochar did not reveal significant deviations in the thermal behavior of biomass grown on chernozem, in contrast to the experiment with red-brown clay, where the addition of biochar contributed to a significant reduction in the duration of thermolysis. The first stage of thermolysis of corn biomass was somewhat shorter in the experiment with a bulk layer of chernozem compared to red-brown clay and was accompanied by a lower mass loss. The same trend was observed in the decomposition of holocellulose. At the same time, the destruction of lignin in the version with chernozem lasted longer, the extremum point was shifted to the region of higher temperatures, the speed of the process was almost twice as low as in the version with clay, and the proportion of non-combustible residue was 1,7. times higher. More complete combustion of corn biomass was also observed in the version with biochar.

리그노셀룰로오스의 혐기성 분해에 의한 탄수화물과 방향족 화합물의 축적속도 평가

This study evaluated the degradation properties of lignocellulose in methanogenic and sulfate-reducing environment. Carbohydrates and aromatic compounds, which are lignocellulosic degradation products, were analyzed and the accumulation rates were calculated. Seeding microorganisms, as well as leachate from a model landfill reactor composed of a methanogenic and sulfate-reducing environment that hadbeen operatingfor more than three years wereused. To calculate the accumulation rates of carbohydrates and aromatic compounds, serum vials cultured for 12 days were subjected to 3% (volume ratio) toluene. Toluene was used to selectively inhibit the activity of microorganisms while maintaining the activity of the extracellular degrading enzyme. Galactose, glucose, xylose and mannose produced from holocellulose such as office paper and newspaper in the presence of 3% toluene showed a linear increase in carbohydrate accumulation with time in a sulfate-reducing environment. The accumulation rates of glucose and xylose in the sulfate-reducing environment were faster than in the methanogenic environment, indicating that holocellulose decomposition was faster in the sulfate-reducing environment than in the methanogenic environment. For the lignin-derived aromatic compounds produced in newspapers in the presence of 3% toluene, 7 aromatic compounds were identified in the sulfate-reducing environment, compared to 3 aromatic compounds identified in the methanogenic environment. Accumulation rates of benzoic acid and vanillin were faster in the sulfate-reducing environment than in the methanogenic environment, indicating that lignin degradation was faster in the sulfate-reducing environment than in the methanogenic environment.

Insights into the effect of hydrolysis medium on the holocellulose decomposition, furfural, and pseudo‐lignin formation

AbstractIn this work, four different media including aqueous water, acetic acid (AA), HCl, and H2SO4 were used to hydrolyze holocelluloses. The decomposition of holocellulose and pseudo‐lignin formation are discussed. It was found that AA and water are almost comparable in catalyzing holocellulose (HC) decomposition but the former can promote sugar decomposition and therefore pseudo‐lignin formation. In contrast, HCl and H2SO4 are more efficient in HC decomposition and furfural formation; specifically, HCl is extremely potent for HC decomposition and furfural formation but inert for pseudo‐lignin formation. The results confirmed that both hydrogen ions and anions would affect the carbohydrate decomposition; in this case, further study revealed that only concentrated Cl− in the water system can promote the furfural formation but Cl− with relative low concentration will inhibit pseudo‐lignin formation. It is proved that, Cl− can stabilize the intermediates that facilitate the pseudo lignin formation. © 2021 Society of Industrial Chemistry and John Wiley & Sons Ltd.

Studying Changes in the Structure of Thermally Modified Beech Wood by IR Fourier Spectroscopy

Wood of forest beech (Fagus sylvatica L.) has high physical and mechanical properties and is widely used in various industries. In this paper, it is shown that, when exposed to elevated temperatures, changes in the chemical composition of forest beech wood, disordering of bonds in the system of lignin and holocellulose, transformation of lignin, and decomposition of holocellulose caused mainly by the decomposition of part of hemicelluloses occur.

Generalized two-dimensional correlation infrared spectroscopy to reveal the mechanisms of lignocellulosic biomass pyrolysis

As the initial stage of combustion, pyrolysis plays a significant role in the combustion of biomass, a typical solid fuel that contains higher volatile contents than other solid fuels. To better understand the pyrolysis mechanism, we herein employed generalized two-dimensional correlation infrared spectroscopy (2D-PCIS) to analyze the functional group evolution in bamboo chars between 250 and 600 °C, and by combination of the volatile release properties, the biomass pyrolysis process mechanism was speculated. We found that below 250 °C, the hydrogen bonding network within the biomass macromolecular structure was broken, while at 250–300 °C, the branched structures were broken during hydration and decarboxylation reactions, resulting in the formation of H2O, acetic acids, and CO2. The subsequent formation of various phenols between 300 and 350 °C mainly originated from rupture of the ether bridges in the lignin structure. In addition, molecular rearrangement of the intermediates from the decomposition of holocellulose resulted in aromatic ring formation. Interestingly, analysis by 2D-PCIS demonstrated that the aromatic rings bearing adjacent substituents easily formed double active sites following breakage of the branched structures. These structures then easily produced fused ring systems below 400 °C, while dehydrogenation and polycondensation at > 400 °C promoted the formation of fused rings from aromatic rings without adjacent substituents.

Fungal succession and decomposition of Pinus densiflora snags

AbstractFungal decomposition of coarse woody debris has an essential role in the biodiversity and carbon and nutrient dynamics in forest ecosystems. However, our knowledge of the effects of fungal species and within‐stem diversity on wood decay is limited. In this paper, I described the process of wood decay and fungal succession of pine (Pinus densiflora) snags using chronosequence method. The results showed that the decay process differed between sapwood and heartwood. Sapwood decayed faster than heartwood, despite their initial densities being the same. Sapwood decay occurred in two phases. The first phase involved a typical white‐rot process wherein acid‐unhydrolysable residue (lignin) and holocellulose decayed simultaneously. White‐rot species, such as Trichaptum abietinum and Phanerochaete sordida, were the dominant fungi and were likely the functional decomposers in this phase. The second phase involved selective decomposition of holocellulose. The dominant fungi in this phase included soft‐rot species, such as Trichoderma spp., that can decompose holocellulose in wood that was previously delignified by white‐rot species. In contrast to sapwood, heartwood experienced less loss of wood density and no clear change in lignocellulose composition, even in later stages of decay. Dominant fungi in heartwood included the latent inhabitants of living pine trees, such as Ascocoryne cylichnium, which is known to reduce colonization and wood decay by strong decomposers. These results suggest that, in addition to decay‐resistant chemicals present in heartwood, the differences in the fungal communities present in heartwood and sapwood were responsible for the differences in their decay rates.

Shift in fungal communities and associated enzyme activities along an age gradient of managed Pinus sylvestris stands.

Forestry reshapes ecosystems with respect to tree age structure, soil properties and vegetation composition. These changes are likely to be paralleled by shifts in microbial community composition with potential feedbacks on ecosystem functioning. Here, we assessed fungal communities across a chronosequence of managed Pinus sylvestris stands and investigated correlations between taxonomic composition and extracellular enzyme activities. Not surprisingly, clear-cutting had a negative effect on ectomycorrhizal fungal abundance and diversity. In contrast, clear-cutting favoured proliferation of saprotrophic fungi correlated with enzymes involved in holocellulose decomposition. During stand development, the re-establishing ectomycorrhizal fungal community shifted in composition from dominance by Atheliaceae in younger stands to Cortinarius and Russula species in older stands. Late successional ectomycorrhizal taxa correlated with enzymes involved in mobilisation of nutrients from organic matter, indicating intensified nutrient limitation. Our results suggest that maintenance of functional diversity in the ectomycorrhizal fungal community may sustain long-term forest production by retaining a capacity for symbiosis-driven recycling of organic nutrient pools.

Selective Production of Phenolic-rich Bio-oil from Catalytic Fast Pyrolysis of Biomass: Comparison of K3PO4, K2HPO4, and KH2PO4

Phenolic-rich bio-oil can be selectively produced from catalytic fast pyrolysis of biomass impregnated with K3PO4, K2HPO4, or KH2PO4. In this study, the catalytic effects of the three catalysts on the pyrolytic product distribution were investigated and compared via analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) experiments. The results indicated that the three catalysts were all able to inhibit the pyrolytic decomposition of holocellulose to form volatile organic products, while promoting the formation of phenolic compounds from lignin. Hence, phenolic-rich bio-oil could be selectively produced. Among the three catalysts, K3PO4 and K2HPO4 possessed similar capability to increase the yield of the phenolics, which was better than KH2PO4. The phenolic contents among the total pyrolytic products steadily increased as the K3PO4 or K2HPO4 dosage increased. The maximal peak area of the phenolics reached as high as 68.8% (at 50 wt.% K3PO4) or 50.6% (at 50 wt.% K2HPO4) of the total peak area. Therefore, based on these results, K3PO4 was the best catalyst for the selective production of phenolic-rich bio-oil.

Accumulation and decay dynamics of coarse woody debris in a Japanese old‐growth subalpine coniferous forest

AbstractFar less is known about the coarse woody debris (CWD) stock and decay process in temperate Asia compared with that in boreal and temperate Europe and North America. We estimated coniferous CWD stock (logs and snags), decay rate and process, and fungal species responsible for the decay process in a Japanese subalpine coniferous forest. The CWD mass was 42.4 Mg ha−1, which was the greatest among the previous data recorded in temperate Asia. The decay rate calculated using the annual input of CWD divided by CWD accumulation was 0.036 year−1, whereas the decay rate when measured chronosequentially was 0.020–0.023 year−1. The decay process was divided into two phases characterized by different dominant organic chemical constituents. In the first phase, both acid‐unhydrolyzable residue and holocellulose decayed simultaneously, suggestive of the white‐rot process. In the second phase, holocellulose was selectively decomposed and AUR accumulated, suggestive of the brown‐rot process. Nutrients (N, P, K, Na, Mg, and Ca) were mineralized in the first phase but immobilized in the second phase. The fruiting bodies of 26 taxa of fungi were recorded as occurring on CWD in the study area.Trichaptum abietinumandT. fuscoviolaceum, which dominated in the first phase and are known as white‐rot fungi, were assumed to be the main decomposers of lignocellulose in the first phase. Although no known strong wood decomposers dominated the second phase,Laetiporus sulphureusandOligoporus caesius, known as brown‐rot fungi, were expected to participate in the selective decomposition of holocellulose in the second phase.

Decomposition of forest products buried in landfills

The objective of this study was to investigate the decomposition of selected wood and paper products in landfills. The decomposition of these products under anaerobic landfill conditions results in the generation of biogenic carbon dioxide and methane, while the un-decomposed portion represents a biogenic carbon sink. Information on the decomposition of these municipal waste components is used to estimate national methane emissions inventories, for attribution of carbon storage credits, and to assess the life-cycle greenhouse gas impacts of wood and paper products. Hardwood (HW), softwood (SW), plywood (PW), oriented strand board (OSB), particleboard (PB), medium-density fiberboard (MDF), newsprint (NP), corrugated container (CC) and copy paper (CP) were buried in landfills operated with leachate recirculation, and were excavated after approximately 1.5 and 2.5yr. Samples were analyzed for cellulose (C), hemicellulose (H), lignin (L), volatile solids (VS), and organic carbon (OC). A holocellulose decomposition index (HOD) and carbon storage factor (CSF) were calculated to evaluate the extent of solids decomposition and carbon storage. Samples of OSB made from HW exhibited cellulose plus hemicellulose (C+H) loss of up to 38%, while loss for the other wood types was 0–10% in most samples. The C+H loss was up to 81%, 95% and 96% for NP, CP and CC, respectively. The CSFs for wood and paper samples ranged from 0.34 to 0.47 and 0.02 to 0.27gOCg−1 dry material, respectively. These results, in general, correlated well with an earlier laboratory-scale study, though NP and CC decomposition measured in this study were higher than previously reported.

Fungal succession and decomposition of beech cupule litter

AbstractBeech cupule litter is the second largest (next to leaf litter) component of total annual litterfall in mast years, and makes an important contribution to carbon budgets in beech forest soils. We investigated the decomposition processes of beech cupule litter over a 30‐month period with reference to the role of fungal succession in the decomposition of acid‐unhydrolyzable residue (AUR) and holocellulose. During the study period, weight loss of holocellulose occurred, while there was little weight loss of AUR, and 77 % of the original cupule weight remained at the end of the study period. Xylaria sp.1, Geniculosporium sp. and Nigrospora sp. that can attack holocellulose selectively caused mass loss of holocellulose and were responsible for the cupule weight loss. Although the beech cupule is a woody phyllome and its lignocellulose composition is similar to that of coarse woody debris (CWD) rather than leaf litter of beech, the selective decomposition of holocellulose by fungi was similar to the decay process of leaf litter rather than CWD.

Wood decomposing abilities of diverse lignicolous fungi on nondecayed and decayed beech wood

We tested the decay abilities of 28 isolates from 28 lignicolous fungal species (Basidiomycota, Ascomycota and Zygomycota) with the pure culture test. We used beech wood powder in varying moisture conditions and decay stages (nondecayed, intermediately decayed and well decayed) as substrates. The weight loss in wood powder was –0.2–17.8%. Five isolates of Basidiomycota (Bjerkandera adusta, Mycena haematopus, Omphalotus guepiniformis, Trametes hirsuta, Trametes versicolor) caused high weight losses in nondecayed wood. We detected significant effects of decay stage on weight loss in wood in most isolates tested, whereas moisture content rarely had an effect on weight loss. Among Basidiomycota and Xylariaceae in Ascomycota weight loss was greater for nondecayed wood than for intermediately and well decayed wood. In contrast four isolates in Ascomycota (Scytalidium lignicola, Trichoderma hamatum, T. harzianum, T. koningii) caused substantial weight loss in intermediately and well decayed wood, although they rarely caused weight loss in nondecayed wood. Zygomycota caused low weight loss in wood. Wood decay stages also affected decomposition of wood chemical components. Acid-unhydrolyzable residue (AUR) decomposition was reduced, whereas holocellulose decomposition was stimulated by some strains of Basidiomycota and Ascomycota in well decayed wood. T. harzianum in particular caused significant weight loss of holocellulose in well decayed wood, although this fungus caused negligible weight loss of both AUR and holocellulose in nondecayed wood. We discuss these changes in the decay patterns of AUR and holocellulose with varying wood decay stages in relation to the role of fungal decomposition of woody debris in forests.

Changes in soil microbial biomass carbon and enzyme activities under elevated CO 2 affect fine root decomposition processes in a Mongolian oak ecosystem

The relationships between soil microbial properties and fine root decomposition processes under elevated CO 2 are poorly understood. To address this question, we determined soil microbial biomass carbon (SMB-C) and nitrogen (SMB-N), enzymes related to soil carbon (C) and nitrogen (N) cycling, the abundance of cultivable N-fixing bacteria and cellulolytic fungi, fine root organic matter, lignin and holocellulose decomposition, and N mineralization from 2006 to 2007 in a Mongolian oak ( Quercus mongolica Fischer ex Ledebour) ecosystem in northeastern China. The experiment consisted of three treatments: elevated CO 2 chambers, ambient CO 2 chambers, and chamberless plots. Fine roots had significantly greater organic matter decomposition rates under elevated CO 2. This corresponded with significantly greater SMB-C. Changes in the activities of protease and phenol oxidase under elevated CO 2 could not explain the changes in fine root N release and lignin decomposition rates, respectively, while holocellulose decomposition rate had the same response to experimental treatments as did cellulase activity. Changes in cultivable N-fixing bacterial and cellulolytic fungal abundances in response to experimental treatments were identical to those of N mineralization and lignin decomposition rates, respectively, suggesting that the two indices were closely related to fine root N mineralization and lignin decomposition. Our results showed that the increased fine root organic matter, lignin and holocellulose decomposition, and N mineralization rates under elevated CO 2 could be explained by shifts in SMB-C and the abundance of cellulolytic fungi and N-fixing bacteria. Enzyme activities are not reliable for the assessment of fine root decomposition and more attention should be given to the measurement of specific bacterial and fungal communities.

Dynamics of physicochemical properties and occurrence of fungal fruit bodies during decomposition of coarse woody debris of Fagus crenata

The pattern of changes in the physicochemical properties of wood, and its relationship with fungal succession during decomposition of coarse woody debris (CWD) of beech (Fagus crenata Blume) were investigated. In total, 47 snags and 66 logs were assigned to a system of five decay classes, and were used for analysis of the decomposition process. The decomposition process consists of two phases characterized by their dominant organic chemical constituents. In the first phase (decay class 1–3), acid-unhydrolyzable residue (AUR) and holocellulose decreased simultaneously. In the second phase (decay class 3–5), holocellulose decayed selectively. Fruiting bodies of ten fungal taxa occurred frequently on decomposing logs and/or snags. These fungi were divided into early and late colonizers according to their occurrence during CWD decomposition. The relationship between fungal community composition and the physicochemical properties of CWD was analyzed by canonical correspondence analysis (CCA). According to the Monte Carlo permutation test, decay class, water content, and type of CWD (log or snag) significantly affected the fungal community structure. Our results suggested that white-rot basidiomycetes, especially Omphalotus guepiniformis, play a central role in the simultaneous decomposition of AUR and holocellulose in the first phase of decomposition. On the other hand, fungal taxa occurring in the second phase of decomposition may not be responsible for the decomposition of holocellulose. Three possible mechanisms of holocellulose decomposition and AUR accumulation in the second phase of decomposition are proposed and discussed.

GC/MS Characterization of Liquids Generated from Low-Temperature Pyrolysis of Wood

Conventional pyrolysis of beech wood has been carried out for heating temperatures in the range 600−900 K, reproducing conditions of interest in countercurrent fixed-bed gasification. The yields of liquids (water and tars) increase with the heating temperature from about 40 to 55% of dry wood mass, confirming results previously obtained with a laboratory-scale gasifier. Apart from qualitative identification of ∼90 species, GC/MS techniques have been applied to quantify 40−43% of tars (40 species, with major contributions from acetic acid, hydroxypropanone, hydroxyacetaldehyde, levoglucosan, formic acid, syringol, and 2-furaldehyde). Decomposition of holocellulose leads to the formation of furan derivatives and carbohydrates, with a temperature-dominated selectivity toward hydroxyacetaldehyde against levoglucosan. Syringols and guaiacols, originating from primary degradation of lignin, present a maximum for heating temperatures of about 750−800 K whereas, owing to secondary degradation, phenols continuousl...

Effects of organic chemical quality and mineral nitrogen addition on lignin and holocellulose decomposition of beech leaf litter by Xylaria sp.

Mycobiota and chemical composition of bleached and non-bleached portions were studied on leaf litter of beech ( Fagus crenata Blume). By surface sterilization method, two xylariaceous species Xylaria sp. and Geniculosporium sp.1 were dominantly isolated in both portions. Frequency of occurrence of Xylaria sp. was significantly higher in the bleached portion than in the non-bleached portion. In the bleached portion, lignin concentration was lower than in the non-bleached portion, indicating that Xylaria sp. and Geniculosporium sp.1 took part in lignocellulose decomposition in the study site. Effects of organic chemical quality of litters and exogenous mineral nitrogen (NH 4 and NO 3) addition were then investigated on in vitro lignin decomposition by Xylaria sp. Weight loss of lignin was significantly related to lignocellulose index (LCI) for four litter types tested. In NH 4 and NO 3 addition treatments, lignin decomposition was completely and partially suppressed, respectively. Xylaria sp. produced bleaching spots on beech leaf litter in vitro in which lignin concentration was lower than in the non-bleached portion. These results suggest that heterogeneous distribution of carbon and nitrogen resources may control lignin decomposition on the litter by the fungus.