Main Biomass Components Research Articles

Spent lithium-ion battery materials recycling for catalytic pyrolysis or gasification of biomass

This research work studied the pyrolysis characteristics of main biomass components (i.e. cellulose, lignin) in the presence of the spent Li-ion battery cathode (BC) enriched in transition-metals (e.g., Ni, Co). The BC with a good thermostability even at > 700 °C could be used as a catalyst for biomass conversion. The addition methods of BC to biomass such as one-step (directly mixing) and two-step (impregnation-drying) were comparatively studied. The two-step method had a better catalytic effect in biomass pyrolysis, contributing to the reduction of decomposition temperature and activation energy. Significantly, the two-step method had a strong catalytic effect in reducing the content of cellulose-derived sugars and increasing the content of ketones via dehydration and decarboxylation. In addition, the BC used by the two-step method had a high potential for biomass pyrolysis or gasification in promoting the catalytic cracking (i.e. H-transfer) of lignin-derived phenols (tar surrogates) to hydrocarbons and aliphatics (e.g., ketones).

Carbon sequestration characteristics of typical temperate natural grasslands in Ningxia, China

To accurately estimate ecosystem carbon storage of natural grassland in Ningxia, we examined ecosystem carbon storage in four types of typical temperate natural grasslands, including meadow steppe, warm steppe, steppe desert, and desert steppe in Ningxia. The results showed that the total vegetation biomass of meadow steppe, warm steppe, steppe desert and desert steppe were 1178.91, 481.22, 292.80 and 209.09 g·m-2, respectively. Root biomass was the main component of total vegetation biomass of meadow steppe and warm steppe, with a contribution of 73.1% and 56.6%, respectively. Aboveground biomass was the main component of total vegetation biomass of steppe desert and desert steppe, accounting for 50.3% and 47.6%, respectively. Litter made low contribution, being 8.5%, 8.0%, 6.4% and 16.2%, respectively. Ecosystem carbon storage of four typical natural grassland was 13.90, 5.94, 2.69 and 2.37 kg·m-2, vegetation carbon storage was 470.26, 192.23, 117.17 and 83.36 g·m-2, and soil organic carbon storage in 0-40 cm layers were 13.43, 5.75, 2.58 and 2.29 kg·m-2, respectively. Soil organic carbon storage was the main body of the total carbon storage of four typical natural grassland in Ningxia, accounting for 96.6%, 96.8%, 95.6% and 96.5%, respectively. The total vegetation biomass, vegetation carbon storage, soil organic carbon storage and ecosystem carbon storage of four natural grassland types were in the order of meadow steppe＞warm steppe＞steppe desert＞desert steppe.

Overexpression of Mutant Galactose Permease (ScGal2_N376F) Effective for Utilization of Glucose/Xylose or Glucose/ Galactose Mixture by Engineered Kluyveromyces marxianus.

Mutant sugar transporter ScGAL2-N376F was overexpressed in Kluyveromyces marxianus for efficient utilization of xylose, which is one of the main components of cellulosic biomass. K. marxianus ScGal2_N376F, the ScGAL2-N376F-overexpressing strain, exhibited 47.04 g/l of xylose consumption and 26.55 g/l of xylitol production, as compared to the parental strain (24.68 g/l and 7.03 g/l, respectively) when xylose was used as the sole carbon source. When a mixture of glucose and xylose was used as the carbon source, xylose consumption and xylitol production rates were improved by 195% and 360%, respectively, by K. marxianus ScGal2_N376F. Moreover, the glucose consumption rate was improved by 27% as compared to that in the parental strain. Overexpression of both wild-type ScGAL2 and mutant ScGAL2-N376F showed 48% and 52% enhanced sugar consumption and ethanol production rates, respectively, when a mixture of glucose and galactose was used as the carbon source, which is the main component of marine biomass. As shown in this study, ScGAL2-N376F overexpression can be applied for the efficient production of biofuels or biochemicals from cellulosic or marine biomass.

The Effect of Ni-ZSM-5 Catalysts on Catalytic Pyrolysis and Hydro-Pyrolysis of Biomass.

With the demand of energy and re-utilization of wastes, the renewable lignocellulosic biomass, has attracted increasing and significant attention for alleviating the growing energy crisis and environment problems. As main components of lignocellulosic biomass, lignin, cellulose, and hemicellulose are connected by hydrogen bond to form a compact skeleton structure, resulting the trenchant condition of biomass pyrolysis. Also, pyrolysis products of above three main constituents contain a large amount of oxygenates that cause low heating value, high corrosiveness, high viscosity, and instability. Meanwhile, zeolites are of considerable significance to the conversion of lignocellulosic biomass to desirable chemical products on account of fine shape selectivity and moderate acid sites and strength. Among numerous zeolites, ZSM-5-based catalysts have been most extensively studied, and the acidity and porosity of ZSM-5 can be tuned by changing the content of Si or Al in zeolite. Beyond that, doping of other metal elements, such as Mn, Co, Ni, Ga, Ce, Pt, into ZSM-5 is also an efficient way to regulate the strength and density of acid sites in zeolite precisely. This review focused on the recent investigation of Ni-modified microporous ZSM-5 used in catalytic pyrolysis of lignin and cellulose. The application of metal-modified hierarchical ZSM-5 is also covered.

Analysis of the Supercritical Water Gasification of Cellulose in a Continuous System Using Short Residence Times

Supercritical Water Gasification (SCWG) has the capacity to generate fuel gas effluent from wet biomass without previously having to dry the biomass. However, substantial efforts are still required to make it a feasible and competitive technology for hydrogen production. Biomass contains cellulose, hemicellulose and lignin, so it is essential to understand their behavior in high-pressure systems in order to optimize hydrogen production. As the main component of biomass, cellulose has been extensively studied, and its decomposition has been carried out at both subcritical and supercritical conditions. Most previous works of this model compound were carried out in batch reactors, where reaction times normally take place in a few minutes. However, the present study demonstrates that gasification reactions can achieve efficiency levels of up to 100% in less than ten seconds. The effect of temperature (450–560 °C), the amount of oxidant (from no addition of oxidant to an excess over stoichiometric of 10%, n = 1.1), the initial concentration of organic matter (0.25–2 wt.%) and the addition of a catalyst on the SCWG of cellulose in a continuous tubular reactor at short residence times (from 6 to 10 s) have been studied in this work. Hydrogen yields close to 100% in the gas phase were obtained when operating under optimal conditions. Moreover, a validation of the experimental data has been conducted based on the theoretical data obtained from its kinetics.

Fast and Efficient Method to Evaluate the Potential of Eutectic Solvents to Dissolve Lignocellulosic Components

The application of eutectic solvents (ESs) in lignocellulosic biomass fractionation has been demonstrated as a promising approach to accomplish efficient and environmentally friendly biomass valorization. In general, ESs are a combination of two components, a hydrogen-bonding donor and a hydrogen-bonding acceptor, in which the melting point of the mixture is lower than that of the individual components. However, there are plenty of possible combinations to form ESs with the potential to apply in biomass processing. Therefore, the development of fast and effective screening methods to find combinations capable to dissolve the main biomass components—namely cellulose, hemicelluloses, and lignin—is highly required. An accurate and simple technique based on optical microscopy with or without polarized lenses was used in this study to quickly screen and monitor the dissolution of cellulose, xylose (a monomer of hemicelluloses), and lignin in several ESs. The dissolution of these solutes were investigated in different choline-chloride-based ESs (ChCl:UREA, ChCl:PROP, ChCl:EtGLY, ChCl:OXA, ChCl:GLY, ChCl:LAC). Small amounts of solute and solvent with temperature control were applied and the dissolution process was monitored in real time. The results obtained in this study showed that cellulose was insoluble in these ESs, while lignin and xylose were progressively dissolved.

Reduction of iron oxide by lignin: Characteristics, kinetics and superiority

Reduction of iron oxide by biomass (a renewable energy) instead of fossil energy can greatly reduce greenhouse gas (carbon dioxide) emissions. In this work, the reduction characteristics and kinetics of iron oxide by lignin (a main component of biomass) were studied, aiming at efficient utilization of lignin as a renewable and highly reactive carbon substitute for coal. The reduction temperature range of iron oxide by lignin was found to be mainly 750–900 °C. It was also observed that the presence of iron could catalyze the pyrolysis of lignin, while the pyrolysis products of lignin promoted the reduction of iron oxide. An increase in the lignin-to-iron oxide mass ratio lowered the temperature at the maximum mass-loss rate determined by TGA. The activation energy varied, increasing first and then decreasing, while increasing the reaction fraction (α), with the turning point at α = 0.4. Compared with CO and coal, lignin appeared to be superior for reducing iron oxide, owing to the formation of nanometer-thickness carbon film in the process. The temperature at the maximum reduction rate was 134 °C for lignin, much lower than that of coal.

Comparison of Supported Ionic Liquid Membranes and Polymeric Ultrafiltration and Nanofiltration Membranes for Separation of Lignin and Monosaccharides.

Lignin is one of the three main components of lignocellulosic biomass and must be considered a raw material with attractive applications from an economic and ecological point of view. Therefore, biorefineries must have in mind the most adequate processing to obtain high-quality lignin and the separation tasks that play a key role to improve the purity of the lignin. Separation techniques based on membranes are a promising way to achieve these requirements. In this work, the separation performance of the SILM (Supported Ionic Liquid Membrane) formed with [BMIM][DBP] as IL (Ionic Liquid) and PTFE as membrane support was compared to a nanofiltration (NF) membrane (NP010 by Microdyn-Nadir) and two ultrafiltration (UF) membranes (UF5 and UF10 by Trisep). The SILM showed selective transport of Kraft lignin, lignosulphonate, xylose, and glucose in aqueous solutions. Although it was stable under different conditions and its performance was improved by the integration of agitation, it was not competitive when compared to NF and UF membranes, although the latter ones suffered fouling. The NF membrane was the best alternative for the separation of lignosulphonates from monosaccharides (separation factors around 75 while SILM attained only values lower than 3), while the UF5 membrane should be selected to separate Kraft lignin and monosaccharides (separation factors around 100 while SILM attained only values below 3).

Robust Analytical Methods for the Accurate Quantification of the Total Biomass Composition of Mammalian Cells.

Biomass composition is an important input for genome-scale metabolic models and has a big impact on their predictive capabilities. However, researchers often rely on generic data for biomass composition, e.g. collected from similar organisms. This leads to inaccurate predictions, because biomass composition varies between different cell lines, conditions, and growth phases. In this chapter we present protocols for the determination of the biomass composition of Chinese Hamster Ovary (CHO) cells. These methods can easily be adapted to other types of mammalian cells. The protocols include the quantification of cell dry mass and of the main biomass components, namely protein, lipid, DNA, RNA, and carbohydrates. Cell dry mass is determined gravimetrically by weighing a defined number of cells. Amino acid composition and protein content are measured by gas chromatography mass spectrometry. Lipids are quantified by shotgun mass spectrometry, which provides quantities for the different lipid classes and also the distribution of fatty acids. RNA is purified and then quantified spectrophotometrically. The methods for DNA and carbohydrates are simple fluorometric and colorimetric assays adapted to a 96-well plate format. To ensure quantitative results, internal standards or spike-in controls are used in all methods, e.g. to account for possible matrix effects or loss of material. Finally, the last section provides a guide on how to convert the measured data into biomass equations, which can then be integrated into a metabolic model.

Chemical looping gasification of lignin with bimetallic oxygen carriers

Chemical Looping Gasification (CLG) is a promising technology to produce syngas from renewable biomass material without the need for upstream air separation. It has been proposed as an innovative scheme for eliminating the tar through hot gas cleaning after biomass is gasified. Lignin is the main component of biomass and the second-most abundant organic material on the planet. Also, lignin is a waste by-product from integrated bio-refineries. Four bimetallic oxygen carriers (CaFe2O4, CaMn2O4, BaFe2O4 and BaMn2O4) are systemically studied for CLG of biomass-based lignin as fuel source. Based on thermodynamic analysis and online mass spectral data, BaFe2O4 demonstrated the best ability to selectively gasify lignin and had good regeneration, which made it very attractive for potential chemical looping partial oxidation of biomass in commercial applications. All oxygen carriers studied showed the ability to be fully regenerated in the air after reduction. Adding CO2 increased production of CO due to reverse Boudouard reaction (C + CO2 = 2CO) and accelerated both biomass conversion and reaction kinetics of the gasification process in the presence of these bimetallic oxygen carriers.

Combined Ultrasound/Microwave Chemocatalytic Method for Selective Conversion of Cellulose into Lactic Acid

Cellulose is the main component of lignocellulosic biomass. Its direct chemocatalytic conversion into lactic acid (LA), a powerful biobased chemical platform, represents an important, and more easily scalable alternative to the fermentative way. In this paper, we present the selective hydrothermal conversion of cellulose and simple sugars into LA, under mild reaction conditions in presence of ErCl3 grafted on the mesoporous silica (MCM-41) surface. High yields and selectivity were obtained for the conversion of sugars under microwave (MW) irradiation at a relatively low temperature (200 °C) and short reaction times (10 min) under microwave (MW) irradiation. Ultrasounds (US) pre-treatment was investigated to reduce the cellulose crystallinity, before the MW-assisted conversion, providing LA with a yield of 64% within 90 min at 220 °C below the subcritical water conditions with increased operational safety. We finally discuss the scalability of the process and the recyclability of the catalyst.

Advantageous conditions of saccharification of lignocellulosic biomass for biofuels generation via fermentation processes

Processing of lignocellulosic biomass includes four major unit operations: pre-treatment, hydrolysis, fermentation and product purification prior to biofuel generation via anaerobic digestion. The microorganisms involved in the fermentation metabolize only simple molecules, i.e., monosugars which can be obtained by carrying out the degradation of complex polymers, the main component of lignocellulosic biomass. The object of this paper was to evaluate the saccharification conditions and identify the process parameters that should be applied to improve the saccharification efficiency of lignocellulosic biomass, defined as the simple sugars concentration, which was considered as a crucial parameter for hydrogen generation via dark fermentation. Drawing global conclusions about the occurring changes in the biomass requires learning about the nature of the biomass structure and composition at different stages of the process. Therefore, techniques for analysis, as FTIR, HPLC and SEM were applied. The experiment was planned employing Box–Behnken design. The advantageous operating conditions and the composition of saccharification enzymatic cocktail were identified and their values occurred similar in the applied border conditions for all tested biomass types. Analysis of the intermediate solid and liquid streams generated during the pre-treatment procedure revealed several structural and compositional changes in the biomass.

Lignin Depolymerization to BTXs

Lignin, one of the main components of lignocellulosic biomass, is the largest renewable source of aromatics on the planet and presents an extraordinary opportunity for being used in the production of bio-based products. It can be transformed for the substitution of aromatic chemical-derived petrol as BTXs. The wide range of applications that it can be obtained from BTXs building blocks makes the selective depolymerization of lignin a great scientific challenge. This review emphasizes the different strategies for the fragmentation of lignin to monomers or aromatics hydrocarbons. Thus, a by-product traditionally discarded or used for energy generation, it could be valorized into high added-value products.

Torrefaction, pyrolysis and two-stage thermodegradation of hemicellulose, cellulose and lignin

This study aims to investigate the thermal degradation mechanisms of hemicellulose, cellulose, and lignin using pyrolysis–gas chromatography/mass spectrometry. To characterize the decomposition behaviors, the torrefaction, pyrolysis, and their combination of the three constituents are performed using single-shot and double-shot reactions, with emphasis on the influence of torrefaction upon pyrolysis. The analysis suggests that O-acetyl and pentose units contained in the hemicellulose are thermally degraded into acetic acid and furfural in torrefaction, so acetic acid and furfural contents decrease significantly in the pyrolysis of torrefied hemicellulose. The impact of torrefaction upon cellulose is insignificant, resulting from the high thermal stability of the crystalline structure in the cellulose. When the pyrolysis temperature is higher than 300 °C, the cellulose starts to decompose and form organic volatile products. The products from lignin mild torrefaction at 250 °C are not obvious, except for vanillin. The severe torrefaction at 300 °C has a significant influence on lignin pyrolysis, and the pyrolysis of torrefied lignin results in an increase in aromatic compounds. Overall, the analysis suggests that torrefaction can be applied for biomass pyrolysis to stabilize pyrolysis bio-oil, make its composition more uniform, and separate certain chemicals. Based on the thermal degradation of the three main biomass components from torrefaction, pyrolysis, and their combination analyzed by Py-GC/MS, the obtained findings have provided useful insights into the applications of torrefaction, pyrolysis, and their combination for biofuel production.

Improved film formability of oxidized starch-based blends through controlled modification with cellulose nanocrystals

Cellulose and starch are main chemical components of plant biomass, and can be used to produce value-added materials. Herein, cellulose nanocrystals (CNC) was used along with NaClO to prepare oxidized corn starch. Subsequently, the oxidized starch was blended with PVA/glycerol to prepare oxidized starch-based blends for film formation and coating paper. The properties of oxidized starch and film formability were modified by addition of CNC and PVA/glycerol. The oxidized starch showed the highest oxidizing degree at 1.10% with 0.5 wt% CNC and 8.0 wt% NaClO. Oxidized starch-based blends had lower viscosity and better uniformity than that of corn starch. The oxidized starch-based composite film showed the optimal water resistance, surface free energy and air permeability. Blending with 30 wt% PVA, the oxidized starch-based composite film showed the best tensile strength, and a simple structural model was simulated. The three-dimensional structure of coated paper was visualized using computed tomography scan (CT-Scan), and verified the good penetration of starch-based blends. The coated paper showed a more dense structure compared to the control paper, and had better waterproof performance and physical strength properties with oxidized starch with the highest oxidizing degree.

P-Sulfonic acid calix[4]arene: A highly efficient organocatalyst for dehydration of fructose to 5-hydroxymethylfurfural

Biomass is an attractive renewable source of carbon since it has a huge potential as a substituent of the scarce fossil fuels and has been widely exploited to obtain important chemicals such as 5-hydroxymethylfurfural (HMF). Fructose, one of the main components of biomass, has been widely explored as precursor for obtaining HMF. Several efforts have been expended in the search for efficient and reproducible methodologies for the synthesis of HMF, a chemical platform important in the production of fuels and other value-added chemicals. In this work, the organocatalyst p-sulfonic acid calix[4]arene (CX4SO3H) was for the first time employed as a catalyst for fructose dehydration reaction to produce HMF. Various parameters such as temperature, reaction time, catalyst load, fructose concentration and catalytic efficiency of other Brønsted acids were investigated. 1H NMR spectroscopy was successfully used as qualitative and quantitative method in all steps of optimization. Using only 1 mol% of CX4SO3H as the catalyst (DMSO-i-PrOH 20% V/V, 140 °C, 50 mg mL−1 of fructose), 92% yield HMF could be obtained in a relatively short time (45 min). Thus, the present work was able to produce HMF from fructose with high efficiency and metal-free conditions.

Lignin Transformation of One-Year-Old Plants During Anaerobic Digestion (AD).

The aim of the research is to identify the changes which occur in lignin from miscanthus and sorghum, one of the main biomass components, as a result of an anaerobic digestion (AD) process. The percentage content and structure of lignin before and after the fermentation process were analysed using biomass harvested in two growing periods—before and after vegetation. It was shown that plants at different developmental stages differ in lignin content. During plant growth, the lignin structure also changes—the syringyl-to-guaiacyl ratio (S/G) increases, whereas the aliphatic and aromatic structure ratio (Al/Ar) decreases. The AD process leads to an increase in percentage lignin content in cell walls, and the increase is higher for plants harvested during vegetation. It has been shown in studies that the methane fermentation of miscanthus and sorghum produces waste containing a large amount of lignin, the structure of which is altered relative to native lignin. The quantity and the new, simplified structure of lignin create new possibilities for using this aromatic polymer.

Catalytic hydropyrolysis of lignin: Suppression of coke formation in mild hydrodeoxygenation of lignin-derived phenolics

Lignin, with its polyaromatic structure and as a main component of lignocellulosic biomass, is considered as an important renewable source of aromatics which are currently obtained from fossil fuels. Lignin pyrolysis gives a liquid product with a high content of phenolic compounds which can be further upgraded to aromatic hydrocarbons through catalytic approaches. In this work, in-situ catalytic hydropyrolysis combined with a subsequent ex-situ catalytic hydrodeoxygenation step was implemented to achieve an enhanced conversion of kraft lignin into aromatic hydrocarbons. The main point is that the ex-situ catalytic upgrading was conducted at mild conditions (temperature: 350 °C; pressure: 1 atm). HY was used as in-situ catalyst for enhanced decomposition of lignin. Fe/HBeta, FeReOx/MCM-41, Fe/ZrO2 and FeReOx/ZrO2 were used as ex-situ catalyst, among which the oxophilic, mesoporous and mild-acidic catalyst of FeReOx/ZrO2 revealed the highest HDO efficiency. Importantly, FeReOx/MCM-41, Fe/ZrO2 and FeReOx/ZrO2 led to significantly lower yield of coke compared to a zeolite-supported catalyst like Fe/HBeta. This suppression of coke formation is a result of reduced phenolic trapping inside catalyst mainly due to the mesoporosity and moderate acid strength of catalyst.

Comparative evaluation of microalgae strains for CO2 capture purposes

In this paper we have compared eleven microalgae/cyanobacteria strains used for the development of a CO2 capture process. Firstly, we studied the tolerance of the selected strains to the water quality available at the production site. The results confirmed that no toxins were present in the water used; in addition, we confirmed that fertilizers could be utilised as the nutrient source instead of pure chemicals. Secondly, the strains were evaluated in terms of growth rate, biomass productivity and photosynthetic efficiency concluding that Scenedesmus almeriensis, Neochloris oleoabundans and bloom from the River Seine were the most productive, above 1.0 g·L−1·day−1. Thirdly, we determined the biochemical composition of the biomass with the results showing that most of the strains mainly accumulate carbohydrates in the stationary phase, over 60% d.wt.; the exceptions were Neochloris oleoabundans and Chlorella vulgaris, which accumulate lipids, above 20% d.wt. In any case, the performance of the microalgae strains was better than that of cyanobacteria both in terms of biomass productivity and the biochemical composition; consequently, using these types of microorganisms is recommended. By considering a fixed value for the main biomass components, we concluded that the most promising strains were Scenedesmus almeriensis, Neochloris oleoabundans and bloom from the River Seine, yielding a biomass value above 0.6 €·kg−1 and an economic value higher than 0.7 €·m-3·day−1. These figures confirm that, in order to obtain profitable CO2 capture processes and to develop more efficient production systems that reduce current production costs, coupling with wastewater treatment schemes is required.

ISOLATION AND STUDY OF A RECOMBINANT CARBOHYDRASE XYLANASE FROM BACILLUS LICHENIFORMIS

Xylanases are hydrolytic enzymes involved in the degradation of xylan, the main component of plant biomass. In the present study xylanase, XynA, from Kazakh strain Bacillus licheniformis was obtained in recombinant form in Escherichia coli cells. The xynA gene was amplified from the genomic DNA of the B. licheniformis and cloned in pET-28c (+) vector under the control of the promoter of bacteriophage T7. Recombinant XynA was produced in ArcticExpressRP(DE3) cells by plasmid gene expression, protein purification was carried out by metal affinity chromatography. During the study, the dependence of the enzymatic activity of recombinant xylanase on temperature and pH was observed, it was established that xylanase has the highest activity at +50°C and pH of 6.9. The activity units at these values of temperature and pH were1859 per ml of purified protein. The working temperature and pH ranges in which xylanase conserves more than 70% activity from maximum is 40-60°C and 5-8, respectively.
 The data obtained are essential for the use of carbohydrase xylanase from B.licheniformis in biotechnological processes in the processing of vegetable raw materials.