Birch Sawdust Research Articles

Sequential utilization of birch sawdust using a two-step hot water treatment

Sequential utilization of birch sawdust using a two-step hot water treatment

Characterization of Fuel Pellets Made From Rice Husk, Sawdust and Corncob Bond with Cissus Populnea and Manihot Esculenta

There is growing interest in the production of biofuels from biomass wastes. The availability of biomass waste poses the need for technical assessment of pelletisation of biomass waste at industrial production level. The misuse of environmentally friendly and sustainable energy resources and lack of compressed biomass energy products that could enhance fuel quality needs to be addressed. This study intends to determine the energy output from tenary combination of the biomass fuel pellets consisting of rice husks, African birch sawdust, corncobs and their varying mixtures bond with aqueous extract of C. populnea (Cp) and M. esculenta (Me). The combustion characteristics of pellets produced from Rice Husk, African Birch Sawdust, Corncob and their blends (M, M1, M2, M3 and M4) were conducted by the development of an analytical protocol. Pellet admixtures were prepared at each binder ratio of 10% of bulk weight of RH, ABS, corncob and their various blends in the ratios 1:1:1 (M), 1:2:3 (M1), 2:1:3 (M2), 3:1:2 (M3) and 2:3:1 (M4), respectively. The Bulk Density (BD), Ash Contents (AC), Heat Release Rate (HRR) and Calorific Value (CV) of the pellets were measured using established procedures. The result revealed that combustion characteristics of fuel pellets made from Corncob and Blend ratio of 1:2:3 bound with Manihot esculenta gel were enhanced and the fuel pellets possessed sufficient calorific values suitable for energy applications. It was recommended that massive production of fuel pellets from biomass wastes for small and medium scale energy systems could give a positive development to agrarian and rural areas in Nigeria where there is a lot of these resources and lack of stable electrical supply.

Комплексная утилизация лигносодержащих древесных отходов

The recycling of wood processing waste generated at pulp and paper and woodworking enterprises by reusing it in obtaining a high-yield semi-finished product for the production of paper and cardboard has been studied. The economic and environmental feasibility of wood waste recovery is beyond doubt. The aim has been to develop technology and modes for recycling wood waste from the production of high-yield pulp (birch sawdust) and woodworking (coniferous and the mix of coniferous and deciduous chips). In the course of the study, high-yield pulp has been obtained from birch sawdust using continuous technology (at Perm Pulp and Paper Company) and batch technology (at most pulp and paper industry enterprises). Cooking of wood chips has been carried out only using batch technology. It is shown that the recycling of birch sawdust to produce a fibrous semi-finished product for use in the production of paper and cardboard solves an important economic problem of the pulp and paper industry, which is the need to reduce the consumption of pulpwood and preserve forest resources. The process of recycling wood waste does not require changes to current technology. This produces high-yield pulp, which in terms of quality is not inferior to a similar semi-finished product made from birch technological chips and meets the enterprise standards. It has been revealed that wood chips from coniferous and deciduous wood from woodworking enterprises can also be used as a raw material for the production of high-yield pulp, but only together with sawdust from birch wood. High-yield pulp from the chips of coniferous and the mix of coniferous and deciduous wood is obtained with increased yield, but with low mechanical strength, since the neutral-sulfite method is intended for the production of a fibrous semi-finished product only from deciduous wood; coniferous wood is not boiled using this method. High-yield pulp with quality indicators corresponding to the enterprise standards from technological chips is produced by the ratios of chips and sawdust of 50:50 and 70:30. The yield of the semi-finished product from the raw materials of all used compositions is high – 75…82 %. Tests of high-yield pulp obtained from birch sawdust have shown that the fibrous semi-finished product can replace 20 % of the MS-5B waste paper mass in production in the production of paper and cardboard compositions.

Combustion Efficiency of Various Forms of Solid Biofuels in Terms of Changes in the Method of Fuel Feeding into the Combustion Chamber

This study analyzes the combustion of pellets and briquettes made of plant biomass in low-power heating devices powered periodically with fuel being placed on the grate, as well as after modification using an automatic fuel feeding system in the gutter burner. The use of herbaceous biomass in the form of pellets in low-power heating devices with automatic fuel feeding and combustion in a gutter burner is not widely promoted and popular. Therefore, this study used four types of herbaceous waste biomass (wheat straw, rye straw, oat straw and hay) and one type of woody waste biomass (birch sawdust) for testing. The basic chemical characteristics were determined for the raw materials. After appropriate preparation, the selected starting materials were subjected to briquetting and pelleting processes. Selected physical properties were also determined for the obtained biofuels. Biofuels made from birch sawdust had the lowest heat value (16.34 MJ·kg−1), although biofuels made from wheat, rye and hay straw had a slightly lower calorific value, respectively: 16.29; 16.28 and 16.26 MJ·kg−1. However, the calorific value of oat straw biofuels was only 15.47 MJ kg−1. Moreover, the ash content for herbaceous biomass was 2–4 times higher than for woody biomass. Similar differences between herbaceous and woody biomass were also observed for the nitrogen and sulfur content. To burn the prepared biofuels, a domestic grate-fired biomass boiler was used, periodically fed with portions of fuel in the form of pellets or briquettes (type A tests), which was then modified with a gutter burner enabling the automatic feeding of fuel in the form of pellets (type B tests). During the combustion tests with simultaneous timing, the concentration of CO2, CO, NO and SO2 in the exhaust gases was examined and the temperature of the supplied air and exhaust gases was measured. The stack loss (qA), combustion efficiency index (CEI) and toxicity index (TI) were also calculated. The research shows that the use of automatic fuel feeding stabilizes the combustion process. The combustion process is balanced between herbaceous and woody biomass biofuels. Disparities in CO2, CO and Tgas emissions are decreasing. However, during type B tests, an increase in NO emissions is observed. At the same time, the research conducted indicates that the combustion of herbaceous biomass pellets with their automatic feeding into the combustion chamber is characterized by an increase in combustion efficiency, indicating that when the combustion process is automated, they are a good replacement for wood biofuels—both pellets and briquettes.

Изменение свойств почвы и морфометрических параметров пшеницы при внесении биоугля: вегетационный эксперимент

Abstract. The purpose of this work is to evaluate the effect of biochar on the physico-chemical properties of the soil and morphometric and some chemical characteristics of durum wheat (Triticum durum L.) and indirectly assess the availability of macronutrients in the soil-biochar system based on the state of plants. Methods. Biochar was obtained from birch sawdust at a temperature of 500 °C and was applied in the amount of 2 % of the weight of air-dry soil. Results. As a result of the vegetation experiment, it was revealed that the application of biochar led to changes in the properties of heavy-loamy agro-soddy-podzolic soil – a significant increase in the pH values of the water extract and the total nitrogen content, but at the same time – to a significant decrease in the content of total organic carbon content. Despite the improvement of some soil characteristics, the application of biochar did not affect the height of plants, leaf weight, root weight, nitrogen and phosphorus content in leaves and yield, and also negatively affected the total weight of plants and the weight of grains, which decreased by 15 % and 18 %, respectively, compared to control. The application of biochar had an impact on the structure of the wheat root system – its branching increased, while the diameter of the absorbing roots significantly decreased. The experiment also showed an increase in mycorrhization of roots due to the functional structures of the fungus – arbuscules and vesicles. The scientific novelty lies that the application of biochar from birch sawdust, despite the improvement of some physico-chemical characteristics of the soil, negatively affects the growth of wheat. The reaction of the aboveground parts of plants and the root system indirectly indicates a decrease in the availability of nutrients in the soil-biochar system. The results obtained in the work can be used to develop technologies for the use of biochar meliorants in various soils.

The impact of lignin content on the biodegradation of virgin paper pulps in soil and marine environment

Paper pulp is a lignocellulosic fibrous material used in the industrial production of paper and board products. In addition to cellulose and hemicellulose, paper pulp contains 1 to 20% lignin, depending on the raw materials and pulping process used. Lignin is a heterogenous aromatic polymer that is hydrophobic and more resistant to microbial degradation compared to the easily biodegradable cellulose and hemicellulose. In this study, the biodegradation of paper pulps containing varying amounts of lignin was examined in soil and marine environments using ISO testing methods. Lignin significantly reduced the mineralization of paper pulps to CO2 in both environmental conditions, and a strong inverse correlation between lignin content and the mineralization to CO2 was observed. A similar impact was observed with natural materials containing lignin, such as birch sawdust. Since the calculation of biodegradability in most ISO and EN standards is based solely on the concept of mineralization to CO2, materials containing lignin can receive poor values in these tests. The implications of this for standardized requirements of biodegradability and possible options to overcome testing deficiencies are discussed.

Simultaneous elimination of vanadium(V) and sulfamethoxazole from livestock wastewater with nitrogen-impregnated biochar

A cross-linked chitosan-modified birch sawdust biochar (CS@BSBC) was prepared and applied for the simultaneous elimination of vanadium (Ⅴ) and sulfamethoxazole (SMX) from livestock wastewater. The adsorption capacity of V(V) reached 110 mg/g alone while this value was promoted to 150 mg/g for the simultaneous removal of SMX and V(V), and the adsorption effect is optimal at pH 3. The adsorption capacity of SMX reached about 30 mg/g alone, while the SMX’s adsorption capacity droped to 25 mg/g for the simultaneous removal of SMX and V(V). The mechanism studies disclosed that redox reactions occur on the surface of CS@BSBC. As revealed by the XPS spectra, 63 % of V(V) was reduced to V(IV) concurrently pyrolic nitrogen and C−O terminals were oxidized to nitrogen oxide and CO. The treatment mechanism of CS@BSBC described above can provide a reference for the subsequent treatment of livestock wastewater with complex composition and high vanadium content.

Lightweight, thermal insulation, hydrophobic mycelium composites with hierarchical porous structure: Design, manufacture and applications

Mycelium composites offer a sustainable alternative to lightweight petroleum-based plastic products and are attracting great attention in various fields. However, creating a mycelium composite with both superior thermal insulation and mechanical strength remains a significant challenge. Here, different sizes of poplar or birch sawdust arranged in a loose and disordered manner are employed to construct mycelium composites with multiscale hierarchical porous structure, including both meso- and microscale pores. The morphological, biological, and physicochemical properties of the filamentous mycelium and the resulting composites are discussed in terms of how they are influenced by the substrate features and the way they interact with the fungus. Mycelium composites with high porosity (∼93%) demonstrate energy absorption of 32 kJ m−3, cushioning coefficient of 5, thermal conductivity of 0.044 W m−1 K−1, and contact angle of 123°, which is comparable to or even better than expanded polystyrene. Lightweight, thermally insulating, hydrophobic mycelium composites with excellent mechanical properties show broad prospects in construction and packaging.

Production of mycelium-based biomaterial using various substrates

This experiment was carried out to create a biomaterial with mycelium as its main component and binding part. The main object of this research was mycelium of Pleurotus ostreatus. Various substrates were used for mycelium growing: buckwheat husks, onion husks, garlic husks, coconut husk substrate, coffee grounds, birch sawdust, wheat grains, ground wheat, hemp husks, rock wool, and polystyrene. These different substrates and materials were mixed with the mycelium culture and grown for at least three months, with growth monitored weekly. The blocks of grown biomaterial were dried and tested for properties such as water absorption, moisture content, and biodegradation. The conducted studies showed that mycelium can successfully colonise and grow on different substrates, forming biomaterials with different properties. The choice of substrate influenced the physical characteristics of the obtained biomaterials. Mycelium can be used as a sustainable alternative for the production of various biomaterials. The results of this study add to the knowledge in the field of mycelium-based biomaterials and open the way for further research and development of this promising technology.

Activated biocarbons obtained from lignocellulosic precursors as potential adsorbents of ammonia

The investigated materials were new biocarbons: FC (Fir Cone), FS (Fir Sawdust), FB (Fir Bark), BS (Birch Sawdust), BB (Birch Bark), AS (Acacia Sawdust), AB (Acacia Bark), OS (Oak Sawdust), OB (Oak Bark), HS (Hornbeam Sawdust)) obtained via pyrolysis and CO2 activation of wood waste (lignocellulosic biomass). In order to study the influence of the carbon precursor on the physicochemical properties of biocarbons there were used the precursors: cones, sawdust, and bark of various tree species. The obtained adsorbents were characterized based on the results, of the N2 adsorption, scanning electron microscopy (SEM), elemental analysis (CHNS), thermogravimetry (TG), derivative thermogravimetry (DTG), and differential thermal analysis (DTA), Fourier Transform Infrared Spectroscopy FT-IR (ATR) and the Boehm’s titration method as well as pHpzc (the point of zero charge). The adsorption capacity and the temperature-programmed desorption (TPD) of ammonia were also studied. The obtained activated biocarbons were characterized by the large specific surface area (515 to 1286 m2/g) and the total pore volume (0.27 to 0.46 cm3/g) as well as the well-developed microporous structure (76 - 90%). The maximum NH3 adsorption capacity of the activated biocarbon was determined to be 2.93 mmol/g (FC (Fir Cone)). These results prove that the lignocellulosic precursors are appropriate for preparation of environmentally friendly and cost-effective biocarbons.

Ultrasound enhanced destruction of tetracycline hydrochloride with peroxydisulfate oxidation over FeS/NBC catalyst: Governing factors, strengthening mechanism and degradation pathway

In this study, FeS/N-doped biochar (NBC) derived from the co-pyrolysis of birch sawdust and Mohr's salt was applied to evaluate the efficiency of catalyzed peroxydisulfate (PDS) oxidation for tetracycline (TC) degradation. It is found that the combination of ultrasonic irradiation can distinctly enhance the removal of TC. This study investigated the effects of control factors such as PDS dose, solution pH, ultrasonic power, and frequency on TC degradation. Within the applied ultrasound intensity range, TC degradation increases with increasing frequency and power. However, excessive power can lead to a reduced efficiency. Under the optimized experimental conditions, the observed reaction kinetic constant of TC degradation increased from 0.0251 to 0.0474 min−1, with an increase of 89%. The removal ratio of TC also increased from ∼85% to ∼99% and the mineralization level from 45% to 64% within 90 min. Through the decomposition testing of PDS, reaction stoichiometric efficiency calculation, and electron paramagnetic resonance experiments, it is shown that the increase in TC degradation of the ultrasound-assisted FeS/NBC-PDS system was attributed to the increase in PDS decomposition and utilization, as well as the increase in SO4•− concentration. The radical quenching experiments showed that SO4•−, •OH, and O2•− radicals were the dominant active species in TC degradation. TC degradation pathways were speculated according to intermediates from HPLC-MS analysis. The test of simulated actual samples showed that dissolved organic matter, metal ions, and anions in waters can undercut the TC degradation in FeS/NBC-PDS system, but ultrasound can significantly reduce the negative impact of these factors.

Self-Hydrogen Supplied Catalytic Fractionation of Raw Biomass into Lignin-Derived Phenolic Monomers and Cellulose-Rich Pulps.

Lignocellulosic biomass is one of the most well-studied and promising green carbon sources. The fullest utilization of lignocellulosic biomass in hydrogen-free and mild conditions to produce phenolic monomers while preserving cellulose-rich pulps is challenging and has far-reaching significance. Here, we report an innovative strategy to convert lignocellulosic biomass into lignin oils and cellulose-rich pulps without exogenous hydrogen under mild conditions over a Pt/NiAl2O4 catalyst. In this process, the structural hydrogens in hemicellulose acted as a hydrogen source to realize the fractionation and depolymerization of lignin into phenolic monomers while keeping the cellulose intact, which is named self-hydrogen supplied catalytic fractionation (SCF). By using water as a solvent, the theoretical yield of phenolic monomers (46.6 wt %, with propyl(ethyl) end-chained syringol and guaiacol as main products) is achieved at 140 °C for 24 h, with 90% cellulose intact in birch sawdust. This H2-free process can be extended to other biomass (hardwood, softwood, and grass) and can be scaled up. The Pt/NiAl2O4 catalyst also shows good stability in recycling as well as regeneration treatment. This work provides a new strategy to achieve high utilization of lignocellulosic biomass for sustainable biorefinery by using water as a solvent without exogenous hydrogen under mild conditions.

Cultural and Morphological Features of Trametes versicolor (Polyporaceae) Growth on Wood Hydrolyzes Containing Media

Background. Trametes versicolor is a representative of basidiomycota, whose biologically active compounds are used in medicine and industry, so the search for active producers capable of growing on industrial waste and the study of new ways of intensification of growth and synthesis of metabolites are relevant task. Objective. Investigation of the effect of Fagales sawdust extracts on growth, morphological characteristics, and induction of synthesis of oxidizing enzymes by macromycetes of the species T. versicolor in surface culture. Methods. The objects of research were 5 strains of T. versicolor, which were cultivated on the synthetic agarized Norcrans media on Petri dishes. The influence of the sawdust extracts of 3 tree species, which acted as a basis for research media, was studied. The following cultural indicators were investigated: colony size, radial growth rate, and growth rate. The research also covered the study of macromycetes' morphological characteristics and the ability of Fagales sawdust extracts to induce the synthesis of oxidative enzymes. Results. It is established that growth on media with the addition of birch extract is more intense: the radial growth rate is 11.2–13.6 mm/day, while for beech and oak, the growth rate ranges from 11.6–13.1 and 11.5–12.6 mm/day respectively. The highest growth value on all media is recorded for T. versicolor 353. The value of the growth rate on the medium with birch sawdust extracts varied in the range 15.8–92.1, for medium with beech extracts – 19.4–46.1, with oak extracts – 15.5–46,7, and the highest growth value was recorded during the cultivation of T. versicolor 5299. The beech and oak sawdust extracts intensified the synthesis of laccase, peroxidase, and tyrosinase, which was strongly expressed in T. versicolor 353, so it was chosen for further experiments with submerged cultivation. Conclusions. Birch, beech, and oak sawdust extracts can be used to increase the accumulation of T. versicolor biomass while beech and oak sawdust extracts are preferable for the intensification of the synthesis of oxidase-type enzymes.

Enhanced α-glucosidase inhibition activity of exopolysaccharides fractions from mycelium of Inonotus obliquus under addition of birch sawdust lignocellulose component

The addition of lignocellulose in the submerged cultivation of Inonotus obliquus has been considered a feasible alternative to improvement the bioactivity of exopolysaccharides. To investigate the key components of lignocellulose in the synthesis of active polysaccharide by I. obliquus, cellulose and hemicellulose polysaccharides were isolated from birch sawdust and their effects on the production and activity of exopolysaccharides from I. obliquus were evaluated in the present study. Results showed that α-glucosidase inhibition rates of exopolysaccharides in two cellulose polysaccharide groups (C-36 and C-48) and water extracted hemicellulose polysaccharide group (H-0) were significantly increased by 3.44–4.09 times compared with control group. Three polysaccharides fractions (DPC36–1, DPC48–1 and DPH0–1) in above three groups were isolated from I. obliquus using DEAE-52 cellulose chromatography, which were composed of glucose with molecular weight distribution ranging from 13.94 kDa to 74.48 kDa. These results might stimulate the development of mycelium polysaccharides from I. oblqiuus as alternative anti-diabetes agents and provide important insights into the relationship of structure-bioactivity of fungal polysaccharides with cellulose and hemicellulose as carbon source donors.

Влияние депонированной формы комплексного пестицидного препарата на структуру урожая зерновых культур и заболеваемость корневыми гнилями

The use of chemical plant protection products is essential to obtain a quality crop, but entails the risks of spreading pesticides in the biosphere and causing damage to beneficial biota. Therefore, the development of new approaches to the delivery of pesticides, which reduce the negative impact on agroecosystems, is an important direction for sustainable agriculture development. The effect of a complex preparation containing the fungicide tebuconazole and the herbicide tribunuron-methyl, embedded in a biodegradable polymer base of poly(3-hydroxybutyrate) and birch sawdust, on the several indicators was studied: the number of rhizospheric micromycetes of spring wheat cv. Novosibirskaya 15 and spring barley cv. Biom, the effectiveness of root pathogens control, and the structure and quality of the crop. In field experiments, a prolonged fungicidal action of the complex embedded preparation was demonstrated, which was superior in duration and efficiency to the traditional pre-sowing seed dressing. During the growing season, there was a significant (p <0.05) decrease in the number of micromycetes in the rhizosphere of wheat and barley by 1.5-2 times in comparison with the control, as well as a decrease in the prevalence of root phytopathogenic fungi (Alternaria, Bipolaris, and Fusarium). A high level of biological efficiency of the embedded fungicide was demonstrated in different phases of plant development - from 73.4 to 100% on wheat and from 68 to 100% on barley. As a result, the use of a complex embedded preparation increased the yield of spring wheat and barley, respectively, by 10.8 and 4.4 c/ha compared to the control and contributed to the improvement of the grain quality of crops. Keywords: PESTICIDES, EMBEDDING, TEBUCONAZOL, TRIBUNURON-METHYL, POLY(3-HYDROXYBUTYRATE), ROOT ROTS, YIELD, WHEAT, BARLEY

Single-Standard Quantification Strategy for Lignin Dimers by Supercritical Fluid Chromatography with Charged Aerosol Detection.

The increased interest in utilizing lignin as a feedstock to produce various aromatic compounds requires advanced chemical analysis methods to provide qualitative and quantitative characterization of lignin samples along different technology streamlines. However, due to the lack of commercially available chemical standards, routine quantification of industrially relevant lignin oligomers in complex lignin samples remains a challenge. This study presents a novel method for universal quantification of lignin dimers based on supercritical fluid chromatography with charged aerosol detection (CAD). A series of lignin-derived dimeric compounds that have been reported from reductive catalytic fractionation (RCF) were synthesized and used as standards. The applicability of using linear regression instead of quadratic calibration curves was evaluated over a concentration range of 15-125 mg/L, demonstrating that the former calibration method is as appropriate as the latter. The response factors of lignin dimeric compounds were compared to assess the uniformity of the CAD signal, revealing that the CAD response for the tested lignin dimers did not differ substantially. It was also found that the response factors were not dependent on the number of methoxy groups or linkage motifs, ultimately enabling the use of only one calibrant for these compounds. The importance of chromatographic peak resolution in CAD was stressed, and the use of a digital peak sharpening technique was adopted and applied to address this challenge. The developed method was verified and used for the quantification of lignin dimers in an oil obtained by a RCF of birch sawdust.

Characterization of Self-Growing Biomaterials Made of Fungal Mycelium and Various Lignocellulose-Containing Ingredients.

In this study, novel blends of mycelium biocomposites (MB) were developed. Various combinations of birch sawdust and hemp shives with birch bark (BB) and wheat bran (WB) additives were inoculated with basidiomycete Trametes versicolor to produce self-growing biomaterials. MB were characterized according to mycelial biomass increment in final samples, changes in chemical composition, elemental (C, H, N) analyses, granulometry of substrates, water-related and mechanical properties, as well as mold resistance and biodegradability. The mycelial biomass in manufactured MB increased by ~100% and ~50% in hemp and sawdust substrates, respectively. The lignocellulose ingredients during fungal growth were degraded as follows: cellulose up to 7% and 28% in sawdust and hemp substrates, respectively, and lignin in the range of 13% in both substrates. A larger granulometric fraction in hemp MB ensured higher strength property but weakened water absorption (600-880%) performance. Perspective MB combinations regarding strength performance were hemp/BB and pure hemp MB (σ10 0.19-0.20 MPa; E 2.9 MPa), as well as sawdust/WB combination (σ10 0.23 MPa; E 2.9 MPa). WB positively affected fungal biomass yield, but elevated water absorption ability. WB improved compressive strength in the sawdust samples but decreased it in the hemp samples. BB supplement reduced water absorption by more than 100% and increased the density of sawdust and hemp samples. All MB samples were susceptible to mold contamination after full water immersion, with identified fungal genera Rhizopus, Trichoderma and Achremonium. The MB exhibited high biodegradability after 12 weeks' exposure in compost, and are therefore competitive with non-biodegradable synthetic foam materials.

HYDROLYSIS OF PLANT BIOMASS USING RECOMBINANT ALPHA-AMYLASE FROM BACILLUS LICHENIFORMIS AND XYLANASE FROM BACILLUS SONORENSIS

With the reduction of fossil hydrocarbon sources and the increasing need for energy, chemical resources and food, the use of biomass as a renewable source is of great importance. This, in turn, necessitates efficient enzymes for bioconversion of biomass. Enzymes are important in industry because they are biocatalysts for complex chemical processes. The conversion of plant biomass into sugars requires a complex of enzymes whose composition must be adapted to the type of biomass and а pretreatment method. The efficiency of enzymatic hydrolysis can be increased by optimizing the composition of the enzymatic complex, increasing the catalytic activity and stability of the enzymes included in it. A large number of microbial amylases are now commercially available, and they have almost completely replaced chemical starch hydrolysis in the processing industry. The use of bacterial xylanases is a key step in the conversion of lignocellulosic polysaccharides into fermentable sugars for the production of biofuels and value-added products. Enzyme complexes containing both α-amylases and xylanases have found applications in the pulp and paper industry and feed production.
 Recombinant α-amylase and xylanase from Bacillus licheniformis and Bacillus sonorensis, respectively, were obtained using recombinant DNA technology. These enzymes were purified by metal affinity chromatography from the lysate of induced cultures of recombinant strains. Enzymatic hydrolysis of potato starch and birch xylan with these recombinant enzymes was performed. The hydrolysis products of these polysaccharides were studied by thin-layer chromatography. It was found that the products of hydrolysis of potato starch using recombinant α-amylase were maltose and maltooligosaccharides and a small amount of glucose. Xylan was isolated from birch sawdust and hydrolyzed by recombinant xylanase. Detection of the hydrolysis products of xylan showed that xylan is hydrolyzed to oligoxylans with a degree of polymerization of at least 2 monomers. No xylose was detected among the hydrolysis products. The results indicate that α-amylase from Bacillus licheniformis and xylanase from Bacillus sonorensis are endoenzymes.

Unleashing lignin potential through the dithionite-assisted organosolv fractionation of lignocellulosic biomass

The development of biomass pretreatment approaches that, next to (hemi)cellulose valorization, aim at the conversion of lignin to chemicals is essential for the long-term success of a biorefinery. Herein, we discuss a dithionite-assisted organosolv fractionation (DAOF) of lignocellulose in n-butanol and water to produce cellulosic pulp and mono-/oligo-aromatics. The study frames the technicalities of this biorefinery process and relates them to the features of the obtained product streams. We comprehensively identify and quantify all products of interest: solid pulp (acid hydrolysis-HPLC, ATR-FTIR, XRD, SEM, enzymatic hydrolysis-HPLC), lignin derivatives (GPC, GC–MS/FID, 1H–13C HSQC NMR, ICP-AES), and carbohydrate derivatives (HPLC). These results were used for inspecting the economic feasibility of DAOF. In the best process configuration, a high yield of monophenolics was reached (∼20 wt%, based on acid insoluble lignin in birch sawdust). Various other lignocellulosic feedstocks were also explored, showing that DAOF is particularly effective on hardwood and herbaceous biomass. Overall, this study demonstrates that DAOF is a viable fractionation method for the sustainable upgrading of lignocellulosic biomass.

Pyrolysis of different biomass feedstocks impregnated with Mohr’s salt to prepare ferrous sulfide-loaded nitrogen-doped biochar composites for sequestration of aqueous Cr(VI) ions

In this study, nitrogen-doped biochar-loaded FeS nanoparticles (FeS/NBCs) were prepared by directly pyrolyzing biomass feedstocks pretreated by Mohr’s salt ((Fe(NH4)2(SO4)2∙6H2O). The effects of major experimental conditions such as pyrolysis temperature, impregnation ratio, and biomass types on pyrolysis products were investigated. Under the conditions of a pyrolysis temperature of 700 °C and a mass ratio of 1:1, the three biomass feedstockss of coffee shells (CS), jute fibers (JF), and birch sawdust (BS) can be pyrolyzed to obtain FeS/NBCs. The spectral and textural properties of FeS/NBC were characterized by X-ray powder diffraction, Raman scattering, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy scan electron microscopy, transmission electron microscopy and N2 adsorption-desorption technologies. FeS/NBCs were assessed to remove aqueous Cr(VI) ions in a batch model. The results showed that the adsorption of Cr(VI) onto FeS/NBCs obeyed pseudo second-order kinetics and Langmuir isotherm. The theoretical adsorption capacities were estimated to be 204.5, 191.9 and 169.2 mg∙g−1 for FeS/NBC(CS), FeS/NBC(JF) and FeS/NBC(BS) at the intrinsic pH of Cr(VI) solution, respectively. The synergy between surface adsorption and FeS reduction under different pH gave FeS/NBCs outstanding activity to eliminate Cr(VI). This work provides a facile and low-cost strategy to fabricate nitrogen-doped biochar-loaded FeS composites for the treatment of Cr(VI)-contaminated water.