Pretreatment Reagent Research Articles

Utilization of Schiff base ligands to chelate Ag+ for highly specific and sensitive Hg2+/Ag+ immunoassay

In this study, a planar benzothiazole Schiff base derivative ZX1 was designed and synthesized to selectively precipitate silver ions, in conjunction with the immunoassay detection of Hg2+ ions. The silver chelation process was highly effective in the pH range of 7–10, with a silver ion precipitation ratio of 99.9 %. The coordination behavior of ZX1 with Ag+ was studied using a series of spectroscopic measurements, topography analysis and DFT calculation. The shortest bond distances were 2.251 and 2.254 Å between nitrogen atom of thiazole and Ag+. Weak interactions were analyzed using the interaction region indicator (IRI) method and VMD. The immunoassay was developed through an anti-Hg2+/Ag+ monoclonal antibody, which showed similar sensitivities for Ag+ and Hg2+. The selectivity and anti-interference ability of the Schiff base ligands were tested for some hard metal ions and several anions. With co-existence of interference ion Ag+, Hg2+ was detected in rice matrix solution with 77 %∼123.5 % recovery by addition of ZX1 as the masking reagent and 90.3 %∼115 % for wheat matrix. This research provides a promising immunoassay strategy for simultaneous detection of silver ions and mercury ions in food matrix by utilization of Schiff base ligands. This novel Schiff base ligand was then used as the pre-treatment reagent to remove silver ions within 5 min for detection of Hg2+ or detection of both Ag+ and Hg2+ based on a novel bi-specific heavy metal antibody.

Efficient synthesis of lactic acid from cellulose through the synergistic effect of zinc chloride hydrate and metal salts

The chemocatalystic conversion of cellulose, the main component of lignocellulosic biomass, to building-block chemicals in water under mild conditions, is an ideal but highly challenging process due to the robust crystal structure of cellulose. It is also the key to establishing a sustainable biomass-based chemical process. Here, we present a highly efficient and selective chemocatalytic hydrolysis of cellulose using ZnCl2·3H2O hydrate as the pretreatment reagent and water-compatible metal salts - ErCl3 as the catalyst, into lactic acid (LA), which is an important chemical building-block widely utilized in the food industry and in the production of chemicals and biodegradable plastic. With 94.0 % conversion of cellulose, an impressive LA yield of 84.6 % was achieved at 170 °C after 4 h under ambient air pressure in water. High yields of LA were also obtained from other carbohydrates, such as fructose (68.3 %), glucose (52.7 %), starch (54.4 %), and inulin (67 %). A series of experiments demonstrated that Er(III) combination with water catalyzed cascading steps of soluble cellulose into LA after ZnCl2·3H2O hydrate disrupted the hydrogen bonds in the cellulose, Zn(II) played an indirect role by promoting LA formation through inhibition of side reactions. A plausible mechanism was proposed for the chemocatalytic conversion of cellulose to LA.

Mesenchymal Stem Cells for Treating Alzheimer's Disease: Cell Therapy and Chemical Reagent Pretreatment.

As the size of the population aged 65 and older continues to grow, the incidence and mortality rates of Alzheimer's disease (AD) are increasing annually. Unfortunately, current treatments only treat symptoms temporarily and do not alter the patients' life expectancy or course of AD. Mesenchymal stem cells (MSCs) have shown a certain therapeutic potential in neurodegenerative diseases including AD due to their neuroinflammatory regulation and neuroprotective effects. However, the low survival and homing rates of MSCs after transplantation seriously affect their therapeutic effectiveness. Therefore, appropriate in vitro preconditioning is necessary to increase the survival and homing rates of MSCs to improve their effectiveness in treating AD. Here we summarize the therapeutic mechanisms of MSCs in AD and the chemical reagents used for the pretreatment of MSCs.

Pretreatment of Mulberry Twig using Nonionic Surfactant-assisted Ionic Liquid for Zymolysis and Subsequent Bioethanol Production

A natural cellulosic biomass pretreatment process was established to use ionic liquid (IL) for efficient zymolysis and subsequent bioethanol production, the IL 1, 3-Dimethylimidazolium dimethyl phosphate/Tween-80 ([Mmim][DMP]/T80) was selected in view of its high pretreatment function. The productivity of reducing sugars from mulberry twigs pretreated with the IL at 130°C for 0.33 h reached 74.72% after zymolysis for 48 h, while only a 14.62% conversion rate for the sample pretreated by water. The fermentability character of the hydrolyzate, witdrawn from zymolysis, was fermented into bioethanol using Saccharomyces cerevisiae. This kind of microbe could efficiently utilize glucose to produce ethanol with the yield of 0.382 g/g glucose in 30 h fermentation. In conclusion, the ionic liquid pretreatment at low temperatures shows promise as a pretreatment reagent for natural lignocellulosic biomass.

Insights into the Mechanism of Coagulation Pretreatment for Membrane Fouling Control from the Perspective of Organic Removal Based on a Sensitive SEC-DAD-FLD-OCD/OND Method

Organic matters, especially low molecular (LMW) ones, contribute to the serious membrane fouling, but the traditional coagulants cannot efficiently remove LMW substances. Herein, the coagulation-ultrafiltration combined process (C-UF) was applied to the actual lake water treatment, and a novel polyaluminum titanium composite coagulant (PATC) was used as a pretreatment reagent for membrane fouling mitigation. The results indicated that PATC performed better to efficiently remove organic matters than polyaluminium chloride (PAC) and polytitanium chloride (PTC). Notably, PATC could effectively remove building blocks and LMW substances, particularly the protein-like fluorescent substances. The removal mechanism of LMW substances by PATC was mainly the adsorption of amorphous hydrolysates, rather than the charge neutralization of positively charged hydroxy complexes. No matter with or without the cake layer, the control performance of the three coagulants on membrane fouling was consistent with their removal efficiency of organics. It indicated that although the cake layer played an important role in the interception of organics and small particles, it was not the decisive factor in lightning membrane fouling. Improving the removal efficiency of organic substances, especially the LMW component, is the key to alleviate membrane fouling. This work provides a new insight into the effects of the composite coagulant on the removal of various organics and the control of membrane pollution in actual lake water treatment.

A novel cascade glycolic acid pretreatment-alkali degumming method for producing hemp fiber

Hemp fiber is a promising textile resource. Because hemp fibers contain high gum content, an efficient degumming method needs to be developed. This study proposed a novel cascade degumming process coupling organosolv pretreatment and alkali boiling. Glycolic acid was optimally selected as a pretreatment reagent. The cascade process achieved a high lignin removal rate (69.81%) and hemicellulose removal rate (84.83%). The degummed hemp fibers showed excellent properties (4.18 ± 0.99 cN/dtex and 8.34 ± 0.01 dtex). Moreover, the glycolic acid solution could be reused three times without purification. The glycolic acid pretreatment led to decreased consumption of alkali reagents by 96.15%. Furthermore, the effect of glycolic acid pretreatment on lignin removal was analyzed by chemical composition analysis, FTIR, XRD, TGA, GPC, and HSQC NMR analysis. These results indicate that the novel cascade degumming process is an efficient and eco-friendly degumming method.

Microfluidic Mixer for In Situ Ammonia Analysis of Single Cells in Mass Spectrometry.

Mass spectrometry (MS) is a powerful tool for exploring single-cell heterogeneity. However, due to the ultralow absolute content of most substances in a single cell, existing methods can only analyze high-content substances; conventional methods are incompetent for quantitative analysis of important trace-amount small-molecule metabolites such as ammonia and sulfide. Herein, a method integrating single-cell extraction, online derivatization, and MS for multifunctional and more accurate MS analysis is reported. For application, ammonia content in a single cell was analyzed, where the cellular heterogeneity in ammonia metabolism was revealed. First, the extraction room of a microfluidic probe was covered on the target single cell, and the extraction fluid was allowed to flow through a single cell and dissolve cellular ammonia. Then, the ammonia was mixed and reacted with the pretreatment reagent input from another inlet to achieve the derivatization and signal amplification, enhancing the analysis sensitivity on MS. Finally, the sample was sent to MS, and the ammonia content was successfully quantitatively evaluated by analyzing its derivative urotropine, demonstrating the potential of this method to advance single-cell mass spectrometry analysis to higher sensitivity.

Accelerating gold extraction from refractory gold tailings via NH4HF2 pre-treatment

Gold tailings are secondary resources, however, a suitable method to extract the remaining gold has not yet been found. Thus, this study investigated that a gold tailings was pretreated with ammonium bifluoride, which promoted recovery of the remaining gold from the tailings. Ammonium bifluoride affecting the leaching effect may be due to the synergistic effect of fluorine and hydrogen ions. The mechanism was researched with the help of scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analyses. The results indicated that ammonium bifluoride interacted with the silica-bearing mineral in the tailings, which made the surface of the tailings become rougher and more cracks, and thus provided some channels for leaching reagent and exposed the occluded gold, largely facilitating gold dissolution. The preferable pre-treatment conditions were shown as NH4HF2 concentration = 0.7 mol/L, liquid to solid ratio = 5, the temperature = 25 °C, and the time = 4 h. The gold extraction efficiency increased by 48.45 % under the optimized pre-treatment conditions. Additionally, ammonium bifluoride proved to be an environmentally friendly, efficient, and low-costed pre-treatment reagent, being well-suited for promoting gold extraction from gold tailings.

Synthetic nanoprobes for biological hydrogen sulfide detection and imaging

AbstractHydrogen sulfide (H2S) is a gaseous molecule involved in multiple biological and physiological processes, including various diseases such as cancer and neurodegenerative disorders. This has led to the development of various analytical methods to monitor H2S in biological settings. Among these, fluorescence‐based assays, specifically organic small‐molecule probes, have been thoroughly utilized. They offer good sensitivity and specificity as sensors, and noninvasive detection with high spatiotemporal resolution in in vitro and in vivo imaging. Despite attempts to decrease the rate of photobleaching and enhance the photostability of these dyes, they are still limited by low survival time and complex reagent pretreatment. Fortunately, nanotechnology has been applied to develop effective, highly sensitive, and specific fluorescent nanoprobes. Specifically, nanomaterial‐based H2S probes have emerged as promising candidates for real‐time detection and imaging. In contrast to their organic molecule‐based counterparts, they offer higher versatility in imaging modes due to their unique optical properties, improved photostability and solubility within physiological fluids, as well as easily modifiable surfaces and tuneable structures for improved specificity. Recently, many nanomaterial‐based probes, ranging from inorganic nanoparticles to self‐assembled nanocomposites, have been developed. These have, for the most part, achieved sensitive and specific endogenous H2S detection and in vivo imaging. In this review, we evaluate five different nanomaterials currently being researched to detect and image endogenous H2S within the last 5 years. Furthermore, analytical methods associated with the various signal outputs, current challenges in H2S nanoprobe design, and possible future research interests are outlined and discussed.

Efficient methane production from waste activated sludge and Fenton-like pretreated rice straw in an integrated bio-electrochemical system

Integrated microbial electrolysis cell-anaerobic digestion (MEC-AD) systems have demonstrated potential advantages for methane production in the presence of small amounts of residual inhibitors. In this study, a series of tests were conducted to analyse the acidification and methanogenesis performance of pretreated rice straw (RS) in anaerobic digestion (AD) and MEC-AD systems after the addition of Fenton-like reagents. The results indicated that the short-chain acids (SCFAs) accumulations reached 2284.64 ± 21.57 mg COD/L with a dosage ratio of 1/4 (g RS/g VSS sludge) in the MEC-AD system and that methane production increased by 63.8% compared with that of an individual AD system. In the interim, the net energy output reached 1.09 × 103 J/g TCOD, which was 1.23 times higher than that of the AD system. The residual Fe3+/Fe2+ in the pretreatment reagent was capable of promoting acidification and methanogenesis in sludge and RS fermentation. The RS hydrolysis products could constrain methanogenesis, which can be mitigated by introducing an MEC. The microbiological analyses revealed that the MEC strongly increased the enrichment of hydrogenotrophic methanogens, especially Methanobacterium (61.16%). Meanwhile, the Syntrophomonas and Acetobacterium abundances increased to 2.81% and 2.65%, respectively, which suggested the reinforcement of acetogenesis and methanogenesis. Therefore, the enhanced hydrogenotrophic methanogens might have served as the key for enhancing the efficiency of methanogenesis due to the introduction of an MEC.

Bioethanol and succinic acid co-production from imidazole-pretreated soybean hulls

The soybean is an important crop in the world, where soybean hull (SH) comprehends 8–10 % of grain dry matter. SH is rich in carbohydrates, mainly in holocellulose fibers, showing to be a promising bio-based material to generate new bio-products. Imidazole is a promissing solvent for pretreatment of lignocellulosic biomass due its delignificant and depolymerizing power. Besides, this reagent presents low to moderate toxicity against many classes of living organisms. Thus, the thermochemical conversion of SH into fermentable sugars using imidazole was carried out at 120 °C for 1 h. The objective of this work was to use a more sustainable pretreatment reagent for the co-production of second-generation bioethanol and succinic acid from soybean hull. After pretreatment, the solid yield was 57.1 wt.%, consisting principally of cellulose. The cellulose-rich fraction was further hydrolyzed using commercial enzymes and achieving 89.9 wt.% and 95.6 wt.% of glucose and xylose yields, respectively. The hydrolysate was fermented using two yeasts: Saccharomyces cerevisiae and Pichia stipitis. Approximately, from 1 ton of SH, it was estimated that 124.0 kg of bioethanol and 36.5 kg of succinic acid could be obtained using S. cerevisiae, while P. stipitis could achieve productions of 116.2 kg of bioethanol and 20.4 kg of the organic acid. This study demonstrated the co-production of biomolecules of industrial interests, carrying out a more environmentally friendly pretreatment process.

Efficient enzymatic hydrolysis of chitin into N-acetyl glucosamine using alkali as a recyclable pretreatment reagent

In this study, an alkali freeze–thaw pretreatment protocol was investigated to efficiently enhance enzymatic hydrolysis of chitin into GlcNAc at high concentrations.

Facilely reducing recalcitrance of lignocellulosic biomass by a newly developed ethylamine-based deep eutectic solvent for biobutanol fermentation

BackgroundBiobutanol is promising and renewable alternative to traditional fossil fuels and could be produced by Clostridium species from lignocellulosic biomass. However, biomass is recalcitrant to be hydrolyzed into fermentable sugars attributed to the densely packed structure by layers of lignin. Development of pretreatment reagents and processes for increasing surface area, removing hemicellulose and lignin, and enhancing the relative content of cellulose is currently an area of great interest. Deep eutectic solvents (DESs), a new class of green solvents, are effective in the pretreatment of lignocellulosic biomass. However, it remains challenging to achieve high titers of total sugars and usually requires combinatorial pretreatment with other reagents. In this study, we aim to develop novel DESs with high application potential in biomass pretreatment and high biocompatibility for biobutanol fermentation.ResultsSeveral DESs with betaine chloride and ethylamine chloride (EaCl) as hydrogen bond acceptors were synthesized. Among them, EaCl:LAC with lactic acid as hydrogen bond donor displayed the best performance in the pretreatment of corncob. Only by single pretreatment with EaCl:LAC, total sugars as high as 53.5 g L−1 could be reached. Consecutive batches for pretreatment of corncob were performed using gradiently decreased cellulase by 5 FPU g−1. At the end of the sixth batch, the concentration and specific yield of total sugars were 58.8 g L−1 and 706 g kg−1 pretreated corncob, saving a total of 50% cellulase. Utilizing hydrolysate as carbon source, butanol titer of 10.4 g L−1 was achieved with butanol yield of 137 g kg−1 pretreated corncob by Clostridium saccharobutylicum DSM13864.ConclusionsEthylamine and lactic acid-based deep eutectic solvent is promising in pretreatment of corncob with high total sugar concentrations and compatible for biobutanol fermentation. This study provides an efficient pretreatment reagent for facilely reducing recalcitrance of lignocellulosic materials and a promising process for biobutanol fermentation from renewable biomass.

The influences of filler loading on tensile properties and water absorption properties of carbonized sugarcane bagasse filled high density polyethylene (HDPE) composite

This study synthesized carbonized sugarcane bagasse (CSB) filled high density polyethylene (HDPE) composites. The effect of pre-treatment reagent of SB with different concentration of sodium hydroxide (NaOH) was examined. The untreated, treated and carbonized SB were characterized by proximate analysis and functional group analysis. By considering all the characteristics, 7 wt% is the optimum concentration which gave lowest moisture content and highest fixed carbon (FC) content. It was chosen to undergo carbonization process at temperature of 600 °C to produce CSB and used as filler in composites. The filler with different loading was mixed with HDPE via extrusion process. The tensile properties, surface morphology and water absorption behaviour of the bio-composites were evaluated. As filler loading increased, the Young’s modulus was increasing gradually. Meanwhile, the tensile strength and elongation at break were increasing up to 5 wt% but then decreasing as filler content increased due to the formation of filler agglomeration in HDPE matrix. The deterioration of the interfacial adhesion of these composites was confirmed by the SEM observations. The percentage of water absorption is gradually increased with increasing the filler loading. In short, the optimum filler loading at 5 wt% imparts good tensile and water absorption properties of composites.

Effects of Gamma-Valerolactone Assisted Fractionation of Ball-Milled Pine Wood on Lignin Extraction and Its Characterization as Well as Its Corresponding Cellulose Digestion

Gamma-valerolactone (GVL) was found to be an effective, sustainable alternative in the lignocellulose defragmentation for carbohydrate isolation and, more specifically, for lignin dissolution. In this study, it was adapted as a green pretreatment reagent for milled pinewood biomass. The pretreatment evaluation was performed for temperature (140–180 °C) and reaction time (2–4 h) using 80% aqueous GVL to obtain the highest enzymatic digestibility of 92% and highest lignin yield of 33%. Moreover, the results revealed a positive correlation (R2 = 0.82) between the lignin removal rate and the crystallinity index of the treated biomass. Moreover, under the aforementioned conditions, lignin with varying molecular weights (150–300) was obtained by derivatization followed by reductive cleavage (DFRC). 2D heteronuclear single quantum coherence nuclear magnetic resonance (2D-HSQC-NMR) spectrum analysis and gel permeation chromatography (GPC) also revealed versatile lignin properties with relatively high β-O-4 linkages (23.8%–31.1%) as well as average molecular weights of 2847–4164 with a corresponding polydispersity of 2.54–2.96, indicating this lignin to be a heterogeneous feedstock for value-added applications of biomass. All this suggested that this gamma-valerolactone based pretreatment method, which is distinctively advantageous in terms of its effectiveness and sustainability, can indeed be a competitive option for lignocellulosic biorefineries.

Pre-treatment and Suitable Reagent Enabled a Reliable and Consistent for Molecular Detection of Fusarium oxysporum f. sp. cubense Tropical Race 4 (Foc4)

Fusarium wilt which is caused by the soil-borne fungus, Fusarium oxysporum f.sp. cubense (Foc), is one of important diseases in banana plant. Foc tropical race 4 (Foc4) is the most pathogenic race which could infect various banana cultivars including Cavendish cultivar which was previously considered as resistant cultivar. Molecular detection of Foc using PCR analysis is indispensable to determine the race of Foc. We demonstrate a faster DNA isolation procedure described in previous method by substituting sodium acetate precipitation with ammonium acetate precipitation without affecting the result. Based on our experience, some fungal genomes were troublesome to be amplified. We suggested pre-treatment step prior to amplification procedure by incubating fungal DNA in 65°C for 10 minutes for any samples of fungal genome, including stubborn samples, before mixing into PCR mix reagent. PCR reagents should be tested for stubborn samples since some of the reagents were unable to amplify the desired DNA fragment. Pre-treatment and the choice of robust PCR reagent should be taken into consideration for a reliable and consistent Foc4 molecular detection result.

MODERN METHODS FOR CLEANING FAT-AND-OIL WASTE WATERS

The article studied modern cleaning methods and technological schemes of enterprises of the fat-and-oil industry. Based on literary sources, the effi ciency of wastewater treatment by physicochemical treatment methods has been investigated. Reagent pretreatment of wastewater is widely used, and research focuses on the selection of optimal reagents and doses. A modern method for the treatment of fat and oil containing wastewater is biomembrane technology. Classic treatment schemes are often unable to achieve regulatory requirements for the quality of treated wastewater; therefore, the use of membrane bioreactor technology may be in demand for treating food wastewater. The problems of using various methods of purifi cation of fat-and- oilt wastewater are identifi ed. The economic effi ciency of the proposed cleaning methods is determined.

Comprehensive assessment for serum treatment for single antigen test for detection of HLA antibodies

The single antigen test is widely used in the field of transplantation to determine the specificity of HLA antibodies. It will be beneficial to standardize the procedure of the single antigen test among HLA laboratories. It is not uncommon that single antigen testing on native sera fails to detect antibodies with very high concentrations. It has been shown that cleavage products of activated complement components may mask strongly binding antibodies in single antigen testing. To overcome inhibition by the activated complement products, sera are pretreated with ethylenediaminetetraacetic acid (EDTA), dithiothreitol (DTT), or heat inactivation before single antigen testing. However, no studies have been published to systemically compare the impact of these treatments on single antigen testing. The aim of this study is to understand the different effects these treatments may have on single antigen test results. We found that mean fluorescence intensity (MFI) obtained from sera treated with EDTA and heat inactivation were nearly identical, while DTT treatment was less potent to remove the inhibition. In addition, sera dilution did not further increase MFI of antibodies after EDTA treatment. Our results provide guidance to choose a pretreatment reagent for single antigen testing, and to compare studies obtained from laboratories using different treatments.

Evaluation of chlorine dioxide as a supplementary pretreatment reagent for lignocellulosic biomass

Chlorine dioxide (ClO2) is a bleaching reagent used in paper industry. Two different types of pretreatment methods were investigated incorporating ClO2 as a secondary reagent: (a) alkaline followed by ClO2 treatment; (b) dilute-sulfuric acid followed ClO2 treatment. In these methods, ClO2 treatment has shown little effect on delignification. Scheme-a has shown a significant improvement in enzymatic digestibility of glucan far above that treated by ammonia alone. On the contrary, dilute-acid followed by ClO2 treatment has shown negative effect on the enzymatic hydrolysis. The main factors affecting the enzymatic hydrolysis are the changes of the chemical structure of lignin and its distribution on the biomass surface. ClO2 treatment significantly increases the carboxylic acid content and reduces phenolic groups of lignin, affecting hydrophobicity of lignin and the H-bond induced association between the enzyme and lignin. This collectively led to reduction of unproductive binding of enzyme with lignin, consequently increasing the digestibility.

Pretreatment of rice straw by ultrasound-assisted Fenton process

Fenton’s reagent, ultrasound, and the combination of Fenton’s reagent and ultrasound were used to pretreat rice straw (RS) to increase its enzymatic digestibility for saccharification. The characterization shows that compared with ultrasound, Fenton’s reagent pretreatment was more efficient in increasing the specific surface area and decreasing the degree of polymerization (DP) of RS. The enzymatic hydrolysis results showed that the RS pretreated by ultrasound-assisted Fenton’s reagent (U/F-RS), which exhibited the largest specific surface area and the lowest DP value, had the highest enzymatic activity, and the amount of reducing sugar released from U/F-RS at 48h of enzymatic saccharification is about 4 times as large as that from raw RS and 1.5 times as large as that from Fenton’s reagent pretreated RS. The ultrasound-assisted Fenton process provides a reliable and effective method for RS pretreatment.