Cellulose Decomposition Research Articles

Lignin-based flame retardant via sequential purification-nanoparticle formation, and N[sbnd]P coupled chemical modification

A nonhalogenated and ecofriendly flame-retarding material was developed using lignin, one of the main components of lignocellulosic biopolymers. Lignin was purified, dissolved, and formulated as nanoparticles and implemented after processing in an ecofriendly water-based γ-valerolactone (GVL) system at different concentrations. Nitrogen‑phosphorus sequential chemical modification was performed using polyethyleneimine (PEI) and phytic acid (PA), The char residue increased by ≥10 % compared with lignin nanoparticles (LNPs). A 10 wt% lignin-based flame retardant (L-FR) based on the weight of cotton fabric was introduced using a simple dipping method. Compared to existing cotton fabrics, the combustion time of L-FR treated cotton fabrics was reduced by 6.8 s. The maximum flame height was reduced by 5.4 cm, and the charcoal residue increased by 25 %. The flame-retarding mechanism of L-FR involved low-temperature dehydration, thermal decomposition of cellulose by the phosphorus component of PA and generation of expansive gas by the nitrogen component of PEI. These results showed that lignin-based raw material processing, polymer processing, and chemical modification were biomass-based, suggesting that lignin could be converted into an ecofriendly flame retardant, highlighting the feasibility of high-value-added lignin.

Isolation and identification of cellulose decomposition bacteria from the soil of Yunnan province, China

In this experiment sodium carboxymethyl cellulose (CMC-Na) was used as the only carbon source to isolate cellulose decomposing bacteria from the soil of Qiongzhusi Forest Park in Kunming, Yunnan Province. The ratio of hydrolytic circle diameter and colony diameter formed by the strain on cellulose Congo red medium was determined for primary screening, and then the filter paper disintegration test and CMC enzyme activity assay were used for rescreen. A cellulose decomposing bacterium (HS-2) with high enzyme activity was obtained, and its enzyme activity was up to 16.42 U/ml. (U means the unit of activity of enzymes, activity, unit) Gram stain and Spore stain reaction showed that HS-2 strain was Gram-positive Bacillus. The Bacillus strain was identified as Bacillus pumilus on the basis of physiological and biochemical tests, and 16S rDNA sequence analysis. Bangladesh J. Bot. 52(3): 635-641, 2024 (September) Special

Structural studies of β-glucosidase from the thermophilic bacterium Caldicellulosiruptor saccharolyticus

β-Glucosidase from the thermophilic bacterium Caldicellulosiruptor saccharolyticus (Bgl1) has been denoted as having an attractive catalytic profile for various industrial applications. Bgl1 catalyses the final step of in the decomposition of cellulose, an unbranched glucose polymer that has attracted the attention of researchers in recent years as it is the most abundant renewable source of reduced carbon in the biosphere. With the aim of enhancing the thermostability of Bgl1 for a broad spectrum of biotechnological processes, it has been subjected to structural studies. Crystal structures of Bgl1 and its complex with glucose were determined at 1.47 and 1.95 Å resolution, respectively. Bgl1 is a member of glycosyl hydrolase family 1 (GH1 superfamily, EC 3.2.1.21) and the results showed that the 3D structure of Bgl1 follows the overall architecture of the GH1 family, with a classical (β/α)8 TIM-barrel fold. Comparisons of Bgl1 with sequence or structural homologues of β-glucosidase reveal quite similar structures but also unique structural features in Bgl1 with plausible functional roles.

Feasibility and potential of terahertz spectral and imaging technology for Apple Valsa canker detection: A preliminary investigation

Apple Valsa canker (AVC) caused by the Ascomycete Valsa mali, seriously constrains the production and quality of apple fruits. The symptomless incubation characteristics of Valsa mali make it highly challenging to detect AVC at an early infection stage. After infecting the wound of apple bark, the pathogenic hyphae of AVC will expand and colonize the phloem tissue. Meanwhile, various enzymes and toxic substances released by hyphae cause the decomposition of cellulose and lignin, and the generation of poisonous secondary metabolites in bark tissue. However, these early symptoms of AVC are invisible from the bark’s appearance. Fortunately, Terahertz Spectral Imaging (ThzSI) technology with the advantage of penetrating, and fingerprinting is promising for detecting hidden or slight symptoms of the fungal infection. This study is a preliminary investigation of terahertz frequency-domain spectra for AVC in the early stage of infection. Healthy and two-week-infected apple tree branches were prepared for capturing ThzS images, and the spectral data were preprocessed by Multivariate scattering correction (MSC), Savitzky-Golay convolution smoothing (SG), and standard normal variate (SNV) respectively to remove data noise and improve data quality. Principal component analysis (PCA), competitive adaptive reweighted sampling (CARS), and random frog (RFROG) were employed to extract the spectral feature bands to eliminate redundant data and improve computational efficiency. Machine learning models were established based on the spectral features to detect AVC at an early infection stage, where 11 of them exhibited the best performance with F1-score of 99.72%. To further explore disease information in spatial spectra, imaging data were acquired using terahertz imaging technology. Based on imaging data, pseudo-color imaging, histogram equalization, and Otsu segmentation were employed to visualize early infection areas in apple barks. Furthermore, histogram feature (HF), shape feature (SF), and local binary pattern (LBP) extracted from terahertz spectral images were utilized to establish the SVM, RF, and KNN models. HF-SF-KNN and HF-SF-LBP-KNN with the best performance achieved F1-score of 98.82%. This study presents a preliminary application of terahertz spectral and imaging technology for early-stage AVC detection and demonstrates its feasibility. Additionally, it provides a new way to detect AVC, which expands the application of ThzSI technology in tree disease detection in orchards and lays the foundation for further research.

Thermal Behaviour, Chemical Composition and Morphological analysis ofCotton Stalk for Efficient Biochar Production

The escalating concern over air pollution from crop stubble burning necessitates responsible biomass disposal or utilisation. In this study, characterisation of cotton stalk was carried out to assess its feasibility for biochar production. The proximate analysis revealed that cotton stalk had moisture content of 8.65%, bulk density of 215.8 kg m-3, volatile matter of 71.65%, and fixed carbon content of 16.03%. The ultimate analysis showed that cotton stalks were predominantly composed of carbon (64.88%), hydrogen (6.58%) , and oxygen (2.55%), with a low (0.66%) nitrogen content . Thermo-gravimetric analysis (TGA) highlighted the pyrolysis process, identifying a peak temperature of approximately 500°C and distinct stages of thermal degradation: moisture loss up to 150°C, hemicellulose decomposition between 200°C and 300°C, cellulose decomposition from 300°C to 400°C, and lignin decomposition from 400°C to 500°C. X-ray diffraction (XRD) analysis confirmed the presence of crystalline cellulose with a diffraction peak at 2θ = 22.5°, indicating significant structural stability during pyrolysis for biochar production. Fourier-transform infrared (FTIR) spectroscopy revealed characteristic peaks associated with cellulose and lignin, underscoring the retention of essential structural components in biochar during biomass conversion. These analyses demonstrated the potential of cotton stalks as a viable feedstock for biochar production, providing a sustainable method for agricultural waste management and soil health improvement.

Colonization profiles of gut microbiota in goat kids from neonatal to weaning period.

Understanding the colonization and change patterns of gut microbiota is pivotal for comprehending host health. As a newly cultured breed, the studies on the gut microbiota of Tianfu goats remain limited. This study aimed to address this gap by analyzing the microbial composition and colonization patterns of fecal samples collected from goat kids from birth to weaning. Fecal samples were collected on days 0, 7, 14, 21, 28, 35, 42, 49, 53, 55, 57, and 64, and the changes and colonization patterns of microorganisms were analyzed through high-throughput 16S rRNA sequencing. The results showed that the abundance of fecal microbiota in goat kids gradually increased over time, followed by a decrease after weaning and stabilization, with reduced individual differences. The colonization of fecal microorganisms mainly presented three different stages: days 0-14, days 21-49, and days 53-64. During the suckling period, the relative abundance of Proteobacteria (72.34%) was the highest, followed by Firmicutes (21.66%). From 21 days old, the microbiota in goat kids gradually to be diverse, with Lachnospiraceae and Ruminococcaceae being dominant. During post-weaning, Ruminococcaceae (30.98-33.34%) was becoming prominence which helpful for cellulose decomposition. LEfSe analyzed three important time points (d0 vs. d7, d7 vs. d14, d49 vs. d53, LDA score > 4 and p < 0.05), 53 microbial communities with stage differences were identified. Functional prediction using PICRUSt revealed that differential microbial communities are mainly related to carbohydrate and amino acid metabolism pathways. Overall, this study addresses the intricate relationship between ages, diets, and microbiota compositions in Tianfu goat kids, and also offering insights into microorganisms-host interactions.

Microbial diversity and cellulase activity of forest soils and litters

The quantity, composition and cellulase activity of forest soils and litters with deciduous and coniferous tree vegetation on the territory of Natural Park "Vitosha" were investigated. Biogenicity, the rate of decomposition of organic matter and specifically of cellulose decomposition were higher in Fagus sylvatica litters than in Pinus sylvestris. In most soil profiles, the total microflora has higher values in the mixed fermentative and humic layer of the litter compared to the fresh litter. The quantity of microorganisms and cellulase activity decrease in the depth of the soil profiles. In general, non-spore-forming bacteria, followed by mold fungi and bacilli, occupy a major share in the composition of the total microflora in litters and soils, and actinomycetes are less represented. The cellulase activity depends to the highest degree on the non-sporulating bacteria, and the values of the mineralization coefficient on the bacteria assimilating mineral nitrogen. The humidity of the litters and soils has a stronger influence on the development, composition, mineralization and cellulase activity of microorganisms, compared to the altitude.

Influence of potassium addition on phosphorus availability and heavy metals immobility of biochar derived from swine manure

Pyrolysis of animal manure at high temperature is necessary to effectively immobilize heavy metals, while the available phosphorus (P) level in biochar is relatively low, rendering it unsuitable for use as fertilizer. In this study, the pretreatment of swine manure with different potassium (K) sources (KOH, K2CO3, CH3COOK and C6H5K3O7) was conducted to produce a biochar with enhanced P availability and heavy metals immobility. The addition of all K compounds lowered the peak temperature of decomposition of cellulose in swine manure. The percentage of ammonium citrate and formic acid extractable P in biochar increased with K addition compared to undoped biochar, with CH3COOK and C6H5K3O7 showing greater effectiveness than KOH and K2CO3, however, water- extractable P did not exhibit significant changes. Additionally, the available and dissolved Si increased due to the doping of K, with KOH and K2CO3 having a stronger effect than CH3COOK and C6H5K3O7. X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) analysis revealed that K addition led to the formation of soluble CaKPO4 and silicate. In addition, the incorporation of K promoted the transformation of labile copper (Cu) and znic (Zn) into the stable fraction while simultaneously reducing their environmental risk. Our study suggest that the co-pyrolysis of swine manure and organic K represents an effective and valuable method for producing biochar with optimized P availability and heavy metals immobility.

Production of natural cellulose-based microfibres, from oil palm mesocarp fibres and pineapple leaf wastes, as porous supports for further applications

Natural cellulose-based microfibers were obtained through an economical and environmentally sustainable process called alkaline-peroxide purification, from the waste products of oil palm mesocarp fibres (OPMF) and pineapple leaves (PL), with the intention of creating porous, biodegradable, biocompatible, and non-toxic solid supports for use in future processes. The extracted microfibres were then taken through microscopic, spectroscopic and thermal characterisation to establish their cellulosic nature. The scanning electron microscopic (SEM) images of the bleached microfibres (B-OPMF and B-PLF) were cleaner, smoother and porous as compared with that of the unrefined fibres (Ur-OPMF and Ur-PLF). The bleached fibres (B-OPMF and B-PLF) exhibited peaks of C and O, which are indicative of pure cellulose, in the energy-dispersive X-ray spectroscopy (EDS) analysis. The FTIR spectral analysis of the extracted cellulose-based fibres (B-OPMF and B-PLF) exhibited peaks that were similar in composition to the reference cellulose (P-GB). For the thermogravimetric analysis (TGA) analysis, the maximum weight degradation in the reference cellulose (P-GB), occurred at 363.11 °C, in the bleached palm fibres (B-OPMF) at 334.55 °C and in the bleached pineapple leaf fibres (B-PLF) at 375.68 °C which, corresponds to cellulose decomposition. The differential scanning calorimetry (DSC) test verified the microfibers' thermally induced transitions. Therefore, these cellulose-based microfibres could be applied as functionalised microfibre supports for future applications.

Exploring product maturation, microbial communities and antibiotic resistance gene abundances during food waste and cattle manure co-composting

This study proposed combining food waste (FW) and cattle manure (CM) in composting to improve the product maturity. The findings suggested that the inclusion of CM effectively extended the thermophilic stage, facilitated the decomposition of cellulose, and enhanced the production of humus-like substances by enhancing beneficial microbial cooperation. Adding 40 % CW was optimal to reduce the nitrogen loss, increase the cellulose degradation rate to 22.07 %, increase germination index (GI) to 140 %, and reduce normalized antibiotic resistance gene (ARG) abundances. Adding CW could promote the transformation of protein-like compounds, thereby enhancing the humification process of organic substances. Structural equation modeling further verified that the temperature was the key factor affecting humification production, while the main driver for ARGs was physiochemical parameters. This study shows that co-composting of FW and CM offers the potential to promote humification, reduce ARG abundance, and improve fertilizer quality for utilization of both biowastes in the field.

Effect of Microbial Degradation Treatments on Lignocellulose, Cellulose, and Water-Holding Capacity of Four Typical Forest Fuels from Northeast China

Since forest fuel decomposes slowly and increases the risk of forest fires by accumulating over the years, forest fuel management to accelerate the decomposition process is essential to prevent forest fires and protect forest resources. In this study, we conducted experiments on forest fuels (Pinus sylvestris var. mongholica, Larix gmelinii, Quercus mongolica and Fraxinus mandshurica) in four typical plantation forests in northeast China by adding Trichoderma spp. to investigate the decomposition process and the changes in cellulose, hemicellulose and the water-holding capacity of the fuels. The addition of Trichoderma spp. accelerated the decomposition of cellulose, hemicellulose and lignin in the fuel. Trichoderma spp. promoted the ratio of water absorption and loss, as well as the water-holding capacity of the fuels. The ratio of water absorption and loss reached equilibrium when the decomposition time was up to 35 days, and the addition of Trichoderma spp. increased the maximal water-holding capacity of the fuel. The residual ratio of the four types of fuel degraded by the different treatments was inversely proportional to their maximal water-holding capacities and to the residual ratios of cellulose, hemicellulose and lignin. The residual ratios of degradation of the four fuels under different treatments were linearly related to their maximum water-holding capacity, cellulose, hemicellulose and lignin residual ratios. Trichoderma spp. had a positive effect on the degradation effect and water-holding capacity of fuel on the ground surface of four typical plantation forests. The study is of positive significance for the decomposition of fuel in forests, it promotes the development of biological fire prevention technology and provides a basis for the reinforcement of the management of fuel in forests and the protection of forest resources.

Effective microorganism combinations improve the quality of compost-bedded pack products in heifer barns: exploring pack bacteria-fungi interaction mechanisms

BackgroundCompost-bedded pack barns (CBP) are getting huge attention as an alternative housing system for dairy cows due to their beneficial impact on animal welfare. Effective microorganisms (EM) inoculums are believed to enhance compost quality, improve soil structure and benefit the environment. However, little information is available on the impact of incubation with external EM combinations on the barn environment, compost quality and microbial diversity in CBP. This experiment was carried out to investigate the effect of inoculating different combinations of EM [Lactobacillus plantarum (L), Compound Bacillus (B) and Saccharomyces cerevisiae (S)] on compost quality and microbial communities of CBP products, as well as the relationship with the heifers’ barn environment. CBP barns were subjected to the following four treatments: CON with no EM inoculum, LB/LS/LBS were Incubated with weight ratios of 1:2 (L: B), 1:2 (L: S), 1:1:1 (L: B: S), respectively.ResultsThe EM inoculation (LB, LS, LBS) reduced the concentration of respirable particulate matter (PM10 and PM2.5) in the CBP, and decreased the serum total protein and total cholesterol levels in heifers. Notably, LBS achieved the highest content of high-density lipoprotein compared to other treatments. Microbiome results revealed that EM inoculation reduced the bacterial abundance (Chao1 index) and fungal diversity (Shannon & Simpson indexes), while increasing the relative abundance of various bacterial genera (Pseudomonas, Paracoccus, Aequorivita) and fungi (Pestalotiopsis), which are associated with cellulose decomposition that ultimately resulted in accelerating organic matter degradation and humification. Furthermore, high nutrient elements (TK&TP) and low mycotoxin content were obtained with EM inoculation, with LBS showing a particularly pronounced effect. Meanwhile, LBS contributed to a decline in the proportion of fungal pathogen categories but also led to an increase in fungal saprotroph categories.ConclusionGenerally, EM inoculation positively impacted compost product quality as organic fertilizer and barn environment by modifying the abundance of cellulolytic bacteria and fungi, while inhibiting the reproduction of pathogenic microbes, especially co-supplementing with L, B and S achieved an amplifying effect.

Highly uncondensed lignin extraction in the novel green L-cysteine/lactic acid cosolvent system

Enhancing the efficient isolation of proto-lignin from lignocellulose using sustainable, environmentally friendly solvents has consistently been a key focus in the lignin-first biorefinery strategy for the past years. At the same time, achieving efficient extraction of highly uncondensed active lignin under acidic conditions has posed an insurmountable challenge. In this study, we develop an L-cysteine-assisted binary acidic cosolvent that efficiently separates the uncondensed lignin under 80 ∼ 90 °C treatment, resulting in a lighter color and a recovery yield of up to 60 %. The corresponding delignification rate reached 82.6 %. The obtained lignin exhibited an ideal retention rate (maximum 84.5 %) of alkyl aryl ether bonds (β–O–4) relative to the native lignin in raw material. The resulting residue was free from cellulose decomposition and yielded over 90 % cellulose with a surface-esterified structure. This study establishes a one-step L-cysteine-assisted stabilization methodology that overcomes the challenges of lignin condensation and allows for the fractionation of lignocellulose into highly uncondensed lignin and high-quality cellulose, thus offering new solutions for biorefinery.

Kinetic, gas emission, reaction pathway and interaction mechanism analysis during oxidative pyrolysis of aluminium electrolysis waste with beech wood

The oxidative pyrolysis kinetic, gas emission, reaction pathway and interaction mechanism during oxidative pyrolysis of spent cathode carbon block (SCCB) and beech wood (BW) were investigated via the thermogravimetry combined with Fourier transform infrared spectrometer (TG-FTIR) analysis. The hemicellulose, cellulose, and lignin in BW and the carbon materials and fluoride in SCCB were determined as the main five components based on thermogravimetric experiment. Compared with pure SCCB, the addition of BW increased the comprehensive oxidative pyrolysis index. Furthermore, the total of 44 kinetic parameters were obtained by the Shuffled Complex Evolution (SCE) method, which were used to further forecast the mass loss of the above five main components. The evolved gases were detected by FTIR, and the results indicated that the main gases for BW/SCCB oxidative pyrolysis were CO2, which corresponded to the oxidation of cellulose, lignin and carbon materials. Small amounts of phenols, alcohols, ethers, ketones, aldehydes, carboxylic acids, CO, aromatics, alkene were attributed to the thermal decomposition of hemicellulose and cellulose. Pyrolysis of cellulose and lignin produced small quantities of hydrocarbons. HF was formed by the thermal decomposition of fluoride. Eventually, the reaction pathway was proposed and the possible interaction mechanism was analyzed during the oxidative pyrolysis of BW/SCCB blends.

Investigating the Effects of the Physicochemical Properties of Cellulose-Derived Biocarbon on Direct Carbon Solid Oxide Fuel Cell Performance.

This paper presents a study of the characteristic effects of the physicochemical properties of microcrystalline cellulose and a series of biocarbon samples produced from this raw material through thermal conversion at temperatures ranging from 200 °C to 850 °C. Structural studies revealed that the biocarbon samples produced from cellulose had a relatively low degree of graphitization of the carbon and an isometric shape of the carbon particles. Based on thermal investigations using the differential thermal analysis/differential scanning calorimeter method, obtaining fully formed biocarbon samples from cellulose feedstock was possible at about 400 °C. The highest direct carbon solid oxide fuel cell (DC-SOFC) performance was found for biochar samples obtained via thermal treatment at 400-600 °C. The pyrolytic gases from cellulose decomposition had a considerable impact on the achieved current density and power density of the DC-SOFCs supplied by pure cellulose samples or biochars derived from cellulose feedstock at a lower temperature range of 200-400 °C. For the DC-SOFCs supplied by biochars synthesised at higher temperatures of 600-850 °C, the "shuttle delivery mechanism" had a substantial effect. The impact of the carbon oxide concentration in the anode or carbon bed was important for the performance of the DC-SOFCs. Carbon oxide oxidised at the anode to form carbon dioxide, which interacted with the carbon bed to form more carbon oxide. The application of biochar obtained from cellulose alone without an additional catalyst led to moderate electrochemical power output from the DC-SOFCs. The results show that catalysts for the reverse Boudouard reactions occurring in a biocarbon bed are critical to ensuring high performance and stable operation under electrical load, which is crucial for DC-SOFC development.

Comparative analysis of energy homeostasis regulation at different altitudes in Hengduan Mountain of red-backed vole, Eothenomys miletus, during high-fat diet acclimation: examining gut microbial and physiological interactions.

The study aimed to explore the similarities and differences in gut microorganisms and their functions in regulating body mass in Eothenomys miletus across different altitudes in the Hengduan Mountains when exposed to a high-fat diet. Eothenomys miletus specimens were gathered from Dali (DL) and Xianggelila (XGLL) in Yunnan Province, China, and categorized into control, high-fat (1 week of high-fat diet), and re-feeding groups (1 week of high-fat diet followed by 2 weeks of standard food). The analysis utilized 16S rRNA sequencing to assess the diversity and structure of intestinal microbial communities in E. miletus. The investigation focused on the impact of high-fat diet consumption and different altitudes on gut microbial diversity, structure, and physiological markers. Results revealed that a high-fat diet influenced the beta diversity of gut microorganisms in E. miletus, leading to variations in microbial community structure between the two regions with different altitudes. High-fat food significantly affected body mass, white adipose tissue mass, triglycerides, and leptin levels, but not food intake. Specific intestinal microorganisms were observed in the high-fat groups, aiding in food digestion and being enriched in particular flora. In particular, microbial genera like Lactobacillus and Hylemonella were enriched in the high-fat group of DL. The enriched microbiota in the control group was associated with plant polysaccharide and cellulose decomposition. Following a high-fat diet, gut microbiota adapted to support lipid metabolism and energy supply, while upon re-feeding, the focus shifted back to cellulose digestion. These findings suggested that alterations in gut microbial composition, alongside physiological markers, play a vital role in adaptation of E. miletus to the diverse habitats of the Hengduan Mountains at varying altitudes.

Microbial degradation of cellulose extracted from wheat bran for bioelectricity production using microbial fuel cell

A successful agro-waste management system may recover energy and stabilize waste, among other benefits. The purpose of this research was to analyze the microbiological decomposition of cellulose that has been alkaline extracted and bleached from wheat bran byproducts. The waste lignin stream was used to synthesize biochar for anode modification. Fourier transform infrared spectroscopy showed that O-H and C-H functional groups predominated in extracted cellulose, whereas scanning electron microscopy, X-ray diffraction, and Raman microscopy characterized lignin-derived biochar and cellulose. Pantoea dispersa, isolated from cow dung, was identified as a cellulose-degrading bacteria using 16 S rRNA sequencing. Cellulose-degrading efficiency was measured by hydrolysis zone size around bacterial colonies. To facilitate cellulose breakdown and sustained power production in a microbial fuel cell, the cellulose-degrading bacteria were co-cultured with the Pseudomonas aeruginosa strain at a 1:1 ratio. Cyclic voltammetry, electrochemical impedance spectroscopy, power density, and current density have been investigated under ideal conditions. At a substrate concentration of 2.5 gm/L and internal resistance of 69.5Ω, a modified anode achieved the maximum power density of 9.1 W/m3. Using agro-waste for waste-to-energy is a step toward a circular bioeconomy.

Optimization of Torrefaction Parameters Using Metaheuristic Approach

The probabilistic technique was used to optimize the torrefaction parameters that indirectly influence the yield of end-products obtained through the pyrolysis of biomass. In the same pursuit, pine cones underwent thermal pre-treatment at 210 °C, 220 °C, 230 °C, 240 °C, and 250 °C in the presence of N2 gas with a flowing rate of 0.7 L∙s−1, whereas the duration of the pre-treatment process was 5 min, 10 min, and 15 min at each. To facilitate the processing of pine waste, a muffle furnace was improvised for pilot-scale testing. The thermal process used to carry out torrefaction was quasi-static. The average dynamic head of volatile gases inside the chamber was 1.04 m. The criteria for determining the optimal solution were based on calorific value, solid yield, energy consumption during the pre-treatment process, and ash handling. In absolute terms, time and temperature did not influence the statistical deviation in cellulose and hemicellulose decomposition after thermal pre-treatment. While considering ash content as a primal factor, thermal processing should be conducted for 5 min at 210 °C for the bounded operating conditions, which are similar to the operating conditions obtained experimentally. The optimal solid yield would be obtained if the thermal pre-treatment is performed at 250 °C for 5 min. The solution derived through a simulated annealing technique provided a better convergence with the experimental dataset.

Human activities shape global patterns of decomposition rates in rivers.

Rivers and streams contribute to global carbon cycling by decomposing immense quantities of terrestrial plant matter. However, decomposition rates are highly variable and large-scale patterns and drivers of this process remain poorly understood. Using a cellulose-based assay to reflect the primary constituent of plant detritus, we generated a predictive model (81% variance explained) for cellulose decomposition rates across 514 globally distributed streams. A large number of variables were important for predicting decomposition, highlighting the complexity of this process at the global scale. Predicted cellulose decomposition rates, when combined with genus-level litter quality attributes, explain published leaf litter decomposition rates with high accuracy (70% variance explained). Our global map provides estimates of rates across vast understudied areas of Earth and reveals rapid decomposition across continental-scale areas dominated by human activities.

INCREASING THE EFFICIENCY OF ENZYMATIC HYDROLYSIS OF LIGNOCELLULOSIC MATERIALS BY FREEZING PRETREATMENT

This paper describes the differences between the efficiency of enzymatic hydrolysis of selected lignocellulosic materials after pretreatment by cyclic freezing and thawing. It also discusses the analysis of the positive effect of alkaline conditions on pretreatment. The selected materials were Populus alba L., wheat straw from Triticum aestivum L. and Cannabis sativa. Three pretreatment methods were used to compare the efficiency of enzymatic decomposition of cellulose and cellulose accessibility. The best results show the wheat straw pre-treated at -20°C in the freezer with NaOH addition with a concentration of monosaccharides of 56.6 g.l-1 compared to initial hydrolysed material with a concentration of monosaccharides of 24.4 g.l-1. The results show better digestibility of grass compared to wood dendromass