Optimal Pretreatment Conditions Research Articles

Combined sulfuric acid and choline chloride/glycerol pretreatment for efficiently enhancing enzymatic saccharification of reed stalk

In this study, an efficient combination of pretreatment solvents involving Choline chloride/Glycerol (ChCl/Gly) and H2SO4 was firstly developed to assess the pretreatment performance and determine optimal pretreatment conditions. The results illustrated that the H2SO4-[ChCl/Gly] combination efficiently removed lignin (52.6%) and xylan (80.5%) from the pretreated reed stalk, and subsequent enzymatic hydrolysis yielded 91.1% of glucose. Furthermore, several characterizations were conducted to examine the structural and morphological changes of the reed stalk, revealing apparently enhanced accessibility (128.4 to 522.6 mg/g), reduced lignin surface area (357.9 to 229.5 m2/g), and substantial changes on biomass surface. Based on the aforementioned study, possible mechanisms for the H2SO4-[ChCl/Gly] pretreatment of reed stalks were proposed. The comprehensive understanding of combined H2SO4-[ChCl/Gly] pretreatment system for enhancing the saccharification of the reed stalk was interpreted in this work. Overall, this novel approach could be efficiently applied to pretreat and saccharify reed stalks, empowering the biomass refining industry.

Evaluation of the Effect of Ultrasonic Pretreatment on the Drying Kinetics and Quality Characteristics of Codonopsis pilosula Slices Based on the Grey Correlation Method.

Ultrasonic (US) maltreatment was performed before the vacuum far-infrared drying (VFID) of Codonopsis pilosula (CP) slices to investigate the effects of different US parameters on the drying characteristics and nutrients of CP slices. The grey correlation method with relative correlation degree (ri) as the evaluation measure was used to construct a model for the evaluation of the pretreatment quality of CP and to determine the optimal pretreatment conditions. The results showed that with the increase in US frequency and power, the drying rate increased. Under the conditions of US power of 180 W, frequency of 60 kHz and a pre-treatment time of 30 min, the drying time reduced by 28.6%. The contents of polysaccharide and syringin in dried CP slices pretreated by US increased by 14.7% and 62.0%, respectively, compared to the non-pre-treated samples, while the total flavonoid content decreased by 10.0%. In terms of colour, pretreatment had a certain protective effect on the red colour of dried products. The highest relative correlation (0.574) and the best overall quality of performance were observed at 180 W, 60 kHz and 30 min. Overall, US technology is suitable for the pretreatment processing of CP, which is of great significance to the drying of CP.

Optimizing monosaccharide production from liquid hot water pretreatment and enzymatic hydrolysis of grass-clover press cake

In the present study, clover-grass press cake was treated by liquid hot water at temperatures of 180–200 °C for a reaction time of 5–10 min. Evaluation of pretreatments was based on the monosaccharide yield after enzymatic hydrolysis of the pretreated slurry and solid fraction, respectively. Extraction of up to 48% hemicellulose and 4% cellulose was observed during pretreatment. The optimal pretreatment conditions were identified as 190 °C and 10 min resulting in monosaccharide yields of 90% and 73% of the theoretical maximum by slurry and solid conversion, respectively. At optimal conditions, the C6 monosaccharide yield (83–90%) was fairly equal compared to the C5 monosaccharide yield (56–89%), which increased by slurry conversion due to near-complete monomerization of soluble xylo-oligosaccharides. In this study, we showed that clover-grass press cake possesses considerable potential as feedstock for production of fermentable sugars in a biorefinery context.

Effects of Cold Plasma Pretreatment on the Synthesis of Polysaccharide from Pleurotus ostreatus.

Fungal polysaccharides have attracted wide attention because of their medical pharmaceutical and health care value. So far, many efforts have been made in strain improvement to produce polysaccharides on a large scale at low cost. Here, a novel cold plasma-induced strain improvement technology was employed to pretreat Pleurotus ostreatus CGMCC 5.374 by radio-frequency (RF) low-vacuum cold plasma (LVCP) for the purpose of obtaining a high-yield polysaccharide strain. The optimum pretreatment conditions including discharge power, treatment time, and working pressure were determined by single factor and orthogonal experiment in succession. Furthermore, transcriptome analysis was conducted to study the effects of RF-LVCP on cell metabolism and proliferation. Results showed that under the optimal condition of discharge power of 130 W, treatment time of 25s and working pressure of 140Pa, polysaccharide content in mycelium was increased by 3.16% after 6days in comparison to the original strain. Transcriptome analysis showed that RF-LVCP is helpful for specific gene transcription profiles, Gene Ontology (GO) and KEGG pathways, of which the differentially expressed genes (DEGs) were mainly involve with the up-regulation of polysaccharide transport, physiology, synthesis and metabolism, as well as the down-regulation of polysaccharide hydrolysis and macromolecular degradation.

Hot melt extrusion with low-temperature deposition-coupling control improves the 3D printing accuracy of gelatin/fish pulp recombinant products

The flow properties of original materials directly affect the shape customization of 3D printing. In order to improve the molding quality, the 3D printing equipment was developed, which was characterized by a variable pressure and temperature extrusion unit, a numerical control transmission unit, an extrusion refrigeration unit, and a control box. The optimal pretreatment condition of sturgeon skin was 0.015 M phosphoric acid with higher gel strength (739.27 g), which could be a good substitute for commercial gelatin. The 7% gelatin/fish pulp reconstituted system could exhibit optimum printing properties through an improved 3D printer. The reconstituted system displayed a smoother printing process and superior accuracy during the process of 3D printing, and showed higher apparent viscosity and modulus during the process of cooling and molding. Additionally, the network structure of 3D printing products of reconstituted the gelatin/fish pulp was denser, which showed higher water holding capacity (89.03%), higher hardness (775.64 g), and constant elasticity (0.9853).

Improving the Dyeing Properties of Peanut Skin Extracts to Flax Fabrics by Chitosan Pretreatment

ABSTRACT Using chitosan as pretreatment agent, the dyeing properties of peanut skin extracts (PSE) to flax fabrics were improved. Flax fabrics have excellent comfort property and are loved by many people. However, flax is different to dye, especially with natural dye. In this research, chitosan was used to pretreat flax fabrics and PSE was used to dye the pretreated flax fabric. The optimal conditions of the chitosan pretreatment and dyeing conditions of PSE were investigated according to the K/S value of the dyed flax fabrics. Comparing the original flax fabric, the chitosan pretreated flax fabric significantly improved the absorption to PSE, and the dyed fabrics had an increased K/S value from 0.9 to 3.9, and had good color fastnesses. The main chemical constitution in PSE such as catechin, chitosan, and cellulose of flax fabrics may form hydrogen bond and ionic bond. Chitosan pretreated and dyed flax fabrics had a stronger ability to UV resistance and scavenging free radicals. The fluorescence intensity of the dyed flax fabrics was improved while it was decreased after chitosan pretreatment. Chitosan pretreatment combined PSE dyeing can be used to develop functional flax textiles without using metallic mordants.

Hydrolysate production from sugarcane bagasse using steam explosion and sequential steam explosion-dilute acid pretreatment for polyhydroxyalkanoate fermentation

Polyhydroxyalkanoates (PHAs) are potential alternatives to conventional petroleum-based plastics. One of the barriers to the commercialization of PHAs is its high production cost, which is primarily due to substrate. Agricultural lignocellulosic residues, such as sugarcane bagasse, can be used as substrates to lower production costs. In order to effectively convert the substrate to PHA, sugarcane bagasse must be pretreated. In this study, steam explosion and sequential steam explosion–dilute H2SO4 pretreatment of sugarcane bagasse were optimized to effectively release reducing sugars through enzymatic hydrolysis. Experiments using response surface methodology (RSM) revealed that steam temperature had the greatest influence on lowering sugar content for both sequential and steam explosion pretreatments. The optimum steam explosion conditions were 230 °C steam temperature and 701 s holding time. The concentration of reducing sugars in the enzymatic hydrolysate produced by the hydrolysis of steam-exploded sugarcane bagasse was 6.91 g/L (46.07% yield). On the other hand, the optimum conditions for sequential pretreatment were 230 °C steam explosion temperature, 137 °C dilute acid temperature, 42 min of dilute acid reaction time, and 4.75% w/v H2SO4 concentration, resulting in a hydrolysate with a reducing sugar content of 12.89 g/L (85.93% yield). When steam explosion and diluted H2SO4 pretreatment were combined, a yield increase of reducing sugar of 87% was observed. PHA in the form of polyhydroxybutyrate (PHB) was successfully synthesized using the hydrolysate through bacterial fermentation, with a concentration of 1.99 g/L (16.79% yield) after 24 h. As a result, sequential pretreatment was effective in producing enzymatic hydrolysates from sugarcane bagasse that could be utilized to produce PHA.

Optimization of alkali concentration in the pretreatment of sugarcane bagasse for ethanol production

This study was aimed for the investigation of the effect of pretreatment procedure of alkaline, based on the chemical arrangement, surface morphology, structural composition and enzymatic assimilation of sugarcane bagasse for sugars and ethanol production. Alkali pretreatment (0 to 8% w/v of NaOH) assists to reduce the lignin portion (from 19.57±0.03% to 9.91±0.02%) and increase the cellulose content of the treated SB (from 34.66±0.05% to 63.58±0.05%) simultaneously. The optimal conditions for alkali pretreatment were 8% NaOH charge at 100oC for 90 min. Enzymatic digestibility of alkali treated SB was significantly improved and hydrolysis yield reached to 89.59% glucose and 61.23% xylose at an prime level using Trichoderma viridae. Further hydrolysate of 8% (w/v) alkali treated SB sample was fermented by Saccharomyces cerevisiae to convert sugar into ethanol and yield was 16.81±0.32% in 24 h. Alkali pretreatment was found to be a treatment of choice for cellulose hydrolysis in SB and subsequent sugar acquired for the production of ethanol during fermentation. Bangladesh J. Sci. Ind. Res. 58(2), 89-98, 2023

Effects of various persulfate oxidation pretreatments on enzymatic saccharification efficiency of sugarcane bagasse biomass and the related mechanism

This study explored the impact of different persulfate pretreatments on the substrate characteristics and enzymatic sugar yield of sugarcane bagasse (SCB) and the related mechanisms. We analyzed the biomass composition, physicochemical properties of SCB, enzymatic saccharification efficiency, pure commercial cellulose and lignin degradation dynamics, and ·OH and SO4∙ − generation properties under different persulfate pretreatments. The results revealed that potassium peroxymonosulfate (2KHSO5·KHSO4·K2SO4, PPMS) pretreatment had a significant effect on SCB. Under the optimal pretreatment conditions, SCB pretreated with PPMS showed a reducing sugar yield of 67.98%, a sugar conversion rate of 90.29%, and a lignin removal rate of 87.49%, which were about 2–3 folds those under pretreatment with peroxydisulfate (PDS) including sodium persulfate (Na2S2O8, SPS) and ammonium persulfate ((NH4)2S2O8, APS). PPMS had higher selectivity for lignin degradation and stronger free radical generation ability than PDS, which may be the main contributor to its superior pretreatment performance.

Green Fractionation and Structural Characterization of Lignin Nanoparticles via Carboxylic-Acid-Based Deep Eutectic Solvent (DES) Pretreatment

Green fractionation and a comprehensive overview of lignin molecular structures during the DES (deep eutectic solvent) pretreatment are very important for lignin valorization and the whole biorefinery process. Herein, intractable woody biomass (poplar wood) was pretreated with five types of carboxylic-acid-based DESs (acetamide served as an HBA (hydrogen bond acceptor), propanedioic acid, tartaric acid, malic acid, glutaric acid, and succinic acid served as HBDs (hydrogen bond donors)) under the optimized pretreatment conditions. Results showed that the optimal delignification ratio was achieved for tartaric-acid-based DES at 140 °C for 20 min under microwave-assisted heating. Two-dimensional HSQC NMR data demonstrated that the isolated poplar DES lignin consisted mainly of β-β, β-O-4 (normal and acylated forms), β-5, and esterified p-hydroxybenzoates (PBs) in different contents. Especially, the contents of β-O-4 in the isolated DES lignin fractions varied based on the pretreatment temperature and different chemical compositions of the DES. The antioxidant activity (2,2-diphenyl-1-picrylhydrazyl, DPPH analysis), microstructure (scanning electron microscope, SEM), and molecular weights (gel permeation chromatography, GPC) of the DES lignin fractions demonstrated that the DES delignification promoted the rapid assembly of lignin nanoparticles (LNPs) and could yield homogeneous lignin (1.23 < PDI < 1.58) with controlled nanometer size (30–170 nm) and good antioxidant activity. This study will improve the knowledge of structural changes of lignin during the different carboxylic-acid-based DES pretreatments and maximize the lignin valorization.

Green alkaline fractionation of sugarcane bagasse at cold temperature improves digestibility and delignification without the washing processes and release of hazardous waste

A response surface design was used to pretreat sugarcane bagasse (SB) with urea (U)/potassium hydroxide (K) at low temperatures. Alkaline pretreatment can increase the digestibility of biomass by removing lignin. However, this pretreatment has common issues, such as high-water consumption and liquid waste generation. To address these issues, this study was conducted to perform the UK pretreatment without washing steps. Under optimized pretreatment condition (−20 °C, 7.5 % UK), hemicellulose and lignin removal were increased approximately by 1.4 (26.18–18.86 %) and 1.7 folds (21.25 % to 12.43 %), respectively, while cellulose increased by 1.6-fold (42.39–68.34 %) as compared to control. This enhanced the enzymatic hydrolysis by 3.16-fold (75.15 %). In addition, physicochemical analyses revealed that U facilitates fiber opening, reduces the crystallinity index of cellulose (55.06–49.03 %), and prevents lignin droplet formation from adhering to cellulose. Hence, UK pretreatment can be a promising pretreatment technology for lignocellulosic valorization towards biorefinery without any washing in restoring the liquid substances.

Effects of the Simultaneous Strengthening of the Glass Fiber Surface and Polyamide-6 Matrix by Plasma Treatment and Nanoclay Addition on the Mechanical Properties of Multiscale Hybrid Composites

To strengthen the mechanical properties of a fiber-reinforced plastic without deteriorating its toughness caused by adding nanomaterial, multiscale hybrid composites (MHC) composed of polyamide 6 (PA6), woven glass fibers (WGFs), nanoclay, and various additives were fabricated and characterized. A surfactant was used to improve the dispersion of the nanoclay in the composite, and a compatibilizer and toughening agent were added to enhance the interfacial interactions between the nanoclay and PA6 and the toughness of the MHC, respectively. In addition, the WGFs were pretreated with atmospheric-pressure air plasma to enhance the interfacial bonding between the WGF and the mixture composed of PA6/nanoclay/compatibilizer/toughening agent, which constitutes the matrix. The optimal composition of the PA6 mixture, optimal content of the nanoclay, and optimal conditions of the plasma pretreatment of the WGF surface were experimentally determined. A suitable manufacturing process was employed using a material composition that maximizes the mechanical properties of the MHC by mitigating the toughness deterioration owing to nanoclay addition. An appropriate quantity of the nanoclay increased the tensile properties as well as the elongation at the break of the MHC because the toughening agent prevented the reduction in the degree of elongation caused by increasing the clay content to a certain extent. Moreover, the plasma treatment of the WGF enhanced the flexural properties and impact resistance of the MHC. Therefore, not only the tensile strength, modulus, and elongation at the break of the PA6 nanocomposite, which constitutes the matrix of the MHC, increased up to 39.83, 40.91, and 194.26%, respectively, but also the flexural strength and modulus, absorbed impact energy, and penetration limit of the MHC increased by 20.2, 26.8, 83.7, and 100.0%, respectively.

Understanding triethylammonium hydrogen sulfate ([TEA][HSO4]) pretreatment induced changes in Pennisetum polystachion cell wall matrix and its implications on biofuel yield

Biofuel potential of a widely grown perennial grass, Pennisetum polystachion, was analyzed using triethylammonium hydrogen sulfate ([TEA][HSO4]) pretreatment. The optimum pretreatment condition was selected based on the delignification efficiency. 80% [TEA][HSO4] at 140 °C for 45 min at 10% sample load, yielding high delignification rate (65.8%) was selected as the optimum pretreatment condition. Recycling of [TEA][HSO4] showed up to 90% IL recovery and significant delignification rates. Glucan yield in the biomass increased to 67.8%, whereas digestibility of biomass enhanced from 16.7% to 84.1%. Extensive deferuloylation (88%) and decoumarylation (86.4%) were observed in the sample following pretreatment. Diferulic acids were not detected in pretreated samples indicating their complete removal. HMF (0.1 mg/mL) and furfural (0.001 mg/mL) produced during pretreatment were very low compared to conventional methods. FTIR and XRD confirmed pronounced delignification and hemicellulose dissolution, and FESEM showed a marked difference in the surface morphology, including defibrillation and enhanced porosity. An ethanol yield of 275 mg/g biomass (84.7% of theoretical maxima) was achieved using Saccharomyces cerevisiae MTCC 36 after 15 h of fermentation. The results obtained from the current study can shed light on utilizing P. polystachion as a potential biofuel feedstock using a low-cost ionic liquid [TEA][HSO4].

New perspectives for maximizing sustainable bioethanol production from corn stover

In Egypt, the production of second-generation bioethanol from agricultural waste is a thriving method to compensate the excessive usage as a consequence of the outspread of Covid-19. The profusion and renewability of lignocellulosic biomass urge its utilization as a promising feedstock for bioethanol production. However, functional delignification without affecting the cellulose matrices remains the major obstacle to achieving effective enzyme accessibility. This paper highlights a novel physio-chemical combination for corn stover (CS) pretreatment for bioethanol production. The optimum pretreatment condition was achieved using a mixture of 5% maleic acid (MA) and 3% citric acid (CA) for 30 min at an autoclave temperature of 110 °C leading to produce a pretreated CS (MAC) with 99% hemicellulose removal, 90% cellulose recovery, and 80% lignin removal. Characteristics analyses such as; SEM, FTIR, TGA, EDX, elemental, proximate, ultimate, higher heating value (HHV), and functionalization analyses were performed to emphasize the property and structure change of CS before and after the pretreatment. Then, MAC was hydrolyzed by cellulase enzyme and produced 13.5 g/L glucose yield which was fermented by Saccharomyces cerevisiae and produced 10 g/L bioethanol.

Effect of Drying Pretreatment on Cellulolytic Enzymatic Hydrolysis of Lignin from Napier Grass

Biomass can be a viable supplement and alternative to non-renewable sources of fuel and chemicals. Lignin is an important part of biomass sources which can be used in various chemical and fuel industries. This study explores the pretreatment of lignin from Napier grass using thermal and physical means, as well as extraction of lignin via cellulolytic enzymatic hydrolysis to determine the optimum condition for feedstock pretreatment. Napier grass parts under various drying conditions and particle sizes were treated with enzymes. Moisture analysis, FTIR spectroscopy, UV–Vis analysis, and Klason lignin were carried out to analyze the moisture, functional group, and yield of lignin. Moisture content of the samples were inversely proportional to the drying conditions. The FTIR result showed lower peak intensity for higher drying conditions, while ball-milling showed less reduction in peak intensity. More Klason lignin was extracted under higher drying conditions. The yield of cellulolytic enzymatic lignin (CEL) was found to be more than actual lignin content, suggesting cellulose was not fully degraded. The FTIR spectra of CEL was found to be closer to that of lignin, but purification was still needed. Optimization was carried out by evaluating the statistical significance of each pretreatment effect of the pretreatments.

Promotion of Sugar Extraction from Sewage Sludge by Microwave Combined with Thermal-Alkaline Pretreatment

A large amount of sludge is produced in the process of municipal sewage treatment. The recovery and utilization of large amounts of sugar, protein, lipids and other organic matter from sewage sludge (SS) is of great significance for reducing environmental pressure and producing clean energy. In this study, microwave combined with thermal-alkaline pretreatment was used to accelerate the dissolution of primary sedimentation sludge and the release of intracellular substances, and to promote the extraction of sugar from SS. The results showed that the yield of crude sugar and the extraction efficiency of pure sugar increased with the increase in NaOH dosage. The extraction of crude sugar reached the equilibrium at about 30 min. During the response surface analysis, the optimal pretreatment conditions were determined as follows: the dosage of NaOH was 9.93 mL, and the leaching time and the microwave time were 27.65 min and 33.2 s, respectively. The crude sugar yield and extraction efficiency obtained under this condition were 39.80 ± 3.57% and 89.74 ± 3.61%, respectively. The pretreated sludge and crude sugar were characterized with scanning electron microscopy and Fourier transform infrared spectroscopy. The results showed that the combined use of thermal-alkaline and microwave effectively destroyed the structure of the sludge and increased the yield of crude sugar.

Pretreatment of Arundo donax L. for photo-fermentative biohydrogen production by ultrasonication and ionic liquid

Combined pretreatment methods were assumed to further enhance photo-fermentative biohydrogen production (PFHP) from lignocellulosic biomass. For this purpose, an ultrasonication assisted ionic liquid pretreatment was applied to Arundo donax L. biomass for PFHP. The optimal condition for the combined pretreatment was 16 g/L of 1-Butyl-3-methylimidazolium Hydrogen Sulfate ([Bmim]HSO4) combined with ultrasonication at a solid to liquid ratio (SLR) of 1:10 for 1.5 h under 60 °C. Under this condition, the maximum delignification of 22.9 % was obtained, in addition, the hydrogen yield (HY) and energy conversion efficiency (ECE) were enhanced by 1.5-fold and 46.4 % (p < 0.05) compared to untreated biomass, respectively. Moreover, heat map analysis was performed to evaluate the correlation between pretreatment conditions and corresponding results, suggesting pretreatment temperature had the strongest (absolute value of Pearson’s r was 0.97) linear correlation with HY. Combined multiple energy production approaches might be useful for further improved ECE.

Valorization of Delonix regia Pods for Bioethanol Production

Delonix regia (common name: Flame tree) pods, an inexpensive lignocellulosic waste matrix, were successfully used to produce value-added bioethanol. Initially, the potentiality of D. regia pods as a lignocellulosic biomass was assessed by Fourier-transform infrared spectroscopy (FTIR), which revealed the presence of several functional groups belonging to cellulose, hemicellulose, and lignin, implying that D. regia pods could serve as an excellent lignocellulosic biomass. Response Surface Methodology (RSM) and Central Composite Design (CCD) were used to optimize pretreatment conditions of incubation time (10–70 min), H2SO4 concentration (0.5–3%), amount of substrate (0.02–0.22 g), and temperature (45–100 °C). Then, RSM-suggested 30 trials of pretreatment conditions experimented in the laboratory, and a trial using 0.16 g substrate, 3% H2SO4, 70 min incubation at 90 °C, yielded the highest amount of glucose (0.296 mg·mL−1), and xylose (0.477 mg·mL−1). Subsequently, the same trial conditions were chosen in the downstream process, and pretreated D. regia pods were subjected to enzymatic hydrolysis with 5 mL of indigenously produced cellulase enzyme (74 filter per unit [FPU]) at 50 °C for 72 h to augment the yield of fermentable sugars, yielding up to 55.57 mg·mL−1 of glucose. Finally, the released sugars were fermented to ethanol by Saccharomyces cerevisiae, yielding a maximum of 7.771% ethanol after 72 h of incubation at 30 °C. Conclusively, this study entails the successful valorization of D. regia pods for bioethanol production.

Mechanical Properties and Hydration Mechanism of Coal Flotation Tailing Cemented Filling Materials

Large-scale application of filled coal mining technology has long been limited by conditions such as the cost of filling. Compared to traditional filling materials, coal flotation tailing filling materials (CFTFM) offers advantages such as low cost and excellent performance. The Box–Behnken response surface method was used to investigate the influence of flotation tailing properties on the mechanical properties and hydration mechanisms of the filling material. Ash content, blending, and calcination temperature of the flotation tailings were used as the investigating factors, and uniaxial compressive strength (7d and 28d), slump, and the slurry water secretion rate of the filling material as the evaluation indicators. The results showed that the influence of the flotation tailings on the uniaxial compressive strength (28d) of CFTFM followed the order ash &gt; calcination temperature &gt; doping, with the interaction of ash and calcination temperature having a greater influence on the uniaxial compressive strength. The optimized pre-treatment conditions for the flotation tailings were 59% ash, 30% doping, a calcination temperature of 765 °C, and optimum uniaxial compressive strength of 7.02 MPa. The effect of flotation tailings on the exotherm of CFTFM hydration was determined using a TAM Air isothermal microcalorimeter, mainly in the induction and acceleration phases. Combined with SEM electron microscopy and IR FT-IR analysis of the hydration products, a descriptive model of the CFTFM hydration mechanism was established. CFTFM hydration can be described in three phases: diffusion, hydration, and hardening. The CFTFM prepared in this study is applicable to the integrated mining and charging synergistic mining technology, which can effectively reduce gangue lifting energy consumption and washing process waste, reduce the cost of filling, and can effectively achieve harmless, resourceful, and large-scale disposal of coal-based solid waste.

A method for the infectivity discrimination of enveloped DNA viruses using palladium compounds pre-treatment followed by real-time PCR.

Cultivation-based assays represent the gold standard for the assessment of virus infectivity; however, they are time-consuming and not suitable for every virus type. Pre-treatment with platinum (Pt) compounds followed by real-time PCR has been shown to discriminate between infectious and non-infectious RNA viruses. This study examined the effect of Pt and palladium (Pd) compounds on enveloped DNA viruses, paying attention to two significant pathogens of livestock - bovine herpesvirus-1 (BoHV-1) and African swine fever virus (ASFV). Native or heat-treated BoHV-1 suspension was incubated with the spectrum of Pt/Pd compounds. Bis(benzonitrile)palladium(II) dichloride (BB-PdCl 2) and dichloro(1,5-cyclooctadiene) palladium(II) (PdCl 2-COD) produced the highest differences found between native and heat- -treated viruses. Optimized pre-treatment conditions (1 mM of Pd compound, 15 min, 4°C) were applied on both virus genera and the heat inactivation profiles were assessed. A significant decrease in the detected quantity of BoHV-1 DNA and ASFV DNA after heat-treatment (60°C and 95°C) and consequent incubation with Pd compounds was observed. BB-PdCl 2 and PdCl 2-COD could help to distinguish between infectious and non-infectious enveloped DNA viruses such as BoHV-1 or ASFV.