Acetic Anhydride Research Articles

Facile Separation of Acetic Acid from 1-Ethyl-3-methylimidazolium Acetate Ionic Liquid with the Aid of a Protic Solvent.

1-Ethyl-3-methylimidazolium acetate (EmimAc), an excellent solvent for cellulosic biomass, is expected to be utilized in chemical conversion, such as in biomass acetylation with acetic anhydride. The corresponding carboxylic acid, acetic acid (AcH), is quantitatively generated as a byproduct and should be separated from EmimAc for recycling. However, the strong interaction between EmimAc and AcH makes their separation difficult under moderate conditions. This study examined the efficacy of protic solvents in distillation and extraction to weaken this interaction through solvation or hydrogen-bonding interactions. The separation efficiency of AcH from EmimAc via distillation increased as the boiling point of the protic solvent increased. Water addition was more effective than the addition of alcohols with boiling points similar to those of water such as 1-propanol and 2-butanol. Furthermore, the favorable effect of water addition on the extraction of AcH was confirmed using common organic solvents, such as diisopropyl ether, diethyl ether, and ethyl acetate. The partition coefficient (α) of AcH between the aqueous and organic phases increased with an increasing dielectric constant of the organic solvent, whereas the α value of EmimAc decreased. Repeated treatments in both distillation and extraction facilitated the complete separation of AcH from EmimAc.

Fe-Mn binary oxides improve the methanogenic performance and reduce the environmental health risks associated with antibiotic resistance genes during anaerobic digestion

Increasing evidence indicates that metal oxides can improve the methanogenic performance during anaerobic digestion (AD) of piggery wastewater. However, the impacts of composite metal oxides on the methanogenic performance and risk of antibiotic resistance gene (ARG) transmission during AD are not fully understood. In this study, different concentrations of Fe-Mn binary oxides (FMBO at 0, 250, 500, and 1000 mg/L) were added to AD to explore the effects of FMBO on the process. The methane yield was 7825.1 mL under FMBO at 250 mg/L, 35.2% higher than that with FMBO at 0 mg/L. PICRUSt2 functional predictions showed that FMBO promoted the oxidation of acetate and propionate, and the production of methane from the substrate, as well as increasing the abundances of most methanogens and genes encoding related enzymes. Furthermore, under FMBO at 250 mg/L, the relative abundances of 14 ARGs (excluding tetC and sul2) and four mobile gene elements (MGEs) decreased by 24.7% and 55.8%, respectively. Most of the changes in the abundances of ARGs were explained by microorganisms, especially Bacteroidetes (51.20%), followed by MGEs (11.98%). Thus, the methanogenic performance of AD improved and the risk of horizontal ARG transfer decreased with FMBO, especially at 250 mg/L.

Functional Group Analysis of α-Pinene Oxidation Products Using Derivatization Reactions and High-Resolution Electrospray Ionization Collision-Induced Dissociation Mass Spectrometry.

Oxidation products of monoterpenes (C10H16) play a significant role as precursors for secondary organic aerosol formation. They contain several structural isomers with multifunctional groups. However, only a few of these isomers have been identified experimentally. We describe a measurement technique for identifying oxygen-containing functional groups (carbonyl, carboxyl, and hydroxyl groups) included in monoterpene oxidation products. This technique involves (i) three derivatization reactions (oximation of carbonyls by O-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine, methyl esterification of carboxylic acids by trimethylsilyl diazomethane, and acylation of alcohols by acetic anhydride), (ii) no preseparation high-resolution electrospray ionization mass spectrometry, and (iii) collision-induced dissociation. This technique was applied to functional group analysis of ozonolysis products for α-pinene. Multifunctional groups of known ozonolysis products were accurately identified. Furthermore, we successfully estimated the multifunctional groups of products that have not been previously reported.

Synthesis, characterization, and molecular modeling of novel 1,3,4-oxadiazole derivatives of mefenamic acid

Abstract A novel series of 1,3,4-oxadiazole derivatives of mefenamic acid was obtained by reacting hydrazones of mefenamic acid with anhydrous acetic anhydride. The mefenamic hydrazones were obtained by reacting different substituted aldehydes with mefenamic acid hydrazide. All the compounds were characterized by spectral data and elemental analysis. Molecular docking studies of all the compounds were performed against COX-1/COX-2 enzymes. Compound 4 and compound 10 were found to have the highest potential to bind with COX-1 while compound 3, compound 6, and compound 10 were found to have the highest potential to bind with COX-2 enzyme.

Design, synthesis and antibacterial assessment of novel 4H-chromene analogues

The significant medicinal and pharmacological facts about chromenes (benzopyran) nucleus prompted us to focus on constructing unique chromenes with biological value. New chromene derivatives 2–15 were synthesized, and their antibacterial effectiveness was studied. The reaction of the 2-amino-4H-chromene derivative 1 with a variety of reagents such as acetic anhydride, formic acid, chloroacetyl chloride, cyclopentanone, ethyl acetoacetate, diethyl malonate, aldehydes, and isatin produced derivatives 2–13. Compound 1 was also treated with aromatic amines such as p-toluidine and/or benzene-1,4-diamine with formaldehyde, yielding derivatives 14 and 15, respectively; spectral techniques were used to confirm the predicted structures of all compounds. The antibacterial activity of the recently synthesized compounds was assessed against two types of bacteria, Bacillus subtilis and Escherichia coli. There is encouraging antibacterial activity in compounds 5 and 7.

N-Phenylnorbornenesuccinimide derivatives, agricultural defensive, and enzymatic target selection.

Faced with the need to develop new herbicides with modes of action different to those observed for existing agrochemicals, one of the most promising strategies employed by synthetic chemists involves the structural modification of molecules found in natural products. Molecules containing amides, imides, and epoxides as functional groups are prevalent in nature and find extensive application in synthesizing more intricate compounds due to their biological properties. In this context, this paper delineates the synthesis of N-phenylnorbornenesuccinimide derivatives, conducts biological assays, and carries out in silico investigation of the protein target associated with the most potent compound in plant organisms. The phytotoxic effects of the synthesized compounds (2-29) were evaluated on Allium cepa, Bidens pilosa, Cucumis sativus, Sorghum bicolor, and Solanum lycopersicum. Reaction of endo-bicyclo[2.2.1]hept-5-ene-3a,7a-dicarboxylic anhydride (1) with aromatic amines led to the N-phenylnorbornenesuccinic acids (2-11) with yields ranging from 75% to 90%. Cyclization of compounds (2-11) in the presence of acetic anhydride and sodium acetate afforded N-phenylnorbornenesuccinimides (12-20) with yields varying from 65% to 89%. Those imides were then subjected to epoxidation reaction to afford N-phenylepoxynorbornanesuccimides (21-29) with yields from 60% to 90%. All compounds inhibited the growth of seedlings of the plants evaluated. Substance 23 was the most active against the plants tested, inhibiting 100% the growth of all species in all concentrations. Cyclophilin was found to be the enzymatic target of compound 23. These findings suggest that derivatives of N-phenylnorbornenesuccinimide are promising compounds in the quest for more selective and stable agrochemicals. This perspective reinforces the significance of these derivatives as potential innovative herbicides and emphasizes the importance of further exploring their biological activity on weeds. © 2024 Society of Chemical Industry.

Nanocrystalline (Cu0.5Ni0.5)yFe3−yO4 Ferrites: Synthesis and Characterization

Nanocrystalline materials with the composition of (Cu0.5Ni0.5)yFe3−yO4 and a spinel structure were synthesized by the auto-combustion sol–gel method. The materials were characterized by powder X-ray diffraction, Mössbauer spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and N2 physisorption. A decrease in the unit cell parameter and increase in the crystallite size with a decrease in the copper and nickel content in ferrites were evidenced. Mössbauer analysis determined that iron ions are in the 3+ states in all compositions. Transmission electron microscopy showed that synthesized ferrite materials consisted of nanoparticles with narrow size distributions. The catalytic properties of synthesized ferrites were studied in the reaction of ethyl acetate oxidation and methanol decomposition. The conversion of ethyl acetate and CO2 selectivity increased with temperature, and this effect was most pronounced for (Cu0.5Ni0.5)0.5Fe2.5O4, for which the main part of the particles possessed sizes below 10 nm, and the mean diameter was calculated to be 4.3 nm. The catalytic activity in the reaction of methanol decomposition was the highest for (Cu0.5Ni0.5)0.25Fe2.75O4, and it decreased with the increase in Cu and Ni content in the samples. The analysis of the samples after the catalytic test indicated significant reduction transformations within the catalysts. Under the reaction medium, the spinel phase decomposed through the formation of Hägg carbide.

Physicochemical properties of esterified/crosslinked quinoa starches and their influence on bread quality.

Starch is the main component of quinoa seeds. However, quinoa starch has poor solubility in cold water and poor mechanical resistance and is easily aged, which limit its application. Therefore, modification of its structure to improve its functional properties is necessary. This research used acetic anhydride and sodium trimetaphosphate to modify the structure of starch molecules and investigated their influence on bread quality. The results showed that both esterification and crosslinking prevented the aggregation behavior of starch molecules. Moreover, they both decreased the gelatinization enthalpy change and relative crystallinity of the starch. Compared with native starch, modification significantly decreased the gelatinization temperature from 57.01 to 52.01 °C and the esterified starch exhibited the lowest enthalpy change with a 44.2% decrease. Modified starch increased the specific volume and decreased the hardness and chewiness of bread. Modification did not influence the moisture content in bread but impacted the water retention capacity, depending on the degree of modification. Low and medium degrees of modification improved the water retention capacity during storage. By contrast, a high degree of modification (10 g kg-1 crosslinking agent) decreased the water retention capacity. The dually modified quinoa starch (esterified and crosslinked) showed no influence on the textural properties of bread. This study demonstrated that both esterification and crosslinking significantly improved the functional properties of quinoa starch. Crosslinked or esterified quinoa starches have the potential to improve the textural properties of bakery products. © 2024 Society of Chemical Industry.

An Alternative Method for the Selective Synthesis of Ortho-nitro Anilines Using Bismuth Nitrate Pentahydrate.

Nitroaromatic compounds are important scaffolds used for the syn-thesis of a variety of compounds, such as explosives, herbicides, dyes, perfumes and phar-maceuticals. Bismuth nitrate pentahydrate is a widely used reagent in organic synthesis; how-ever, its utility as a nitrating agent for anilines is underexplored. The aim of this work is to propose and find the proper reaction conditions of an alternative nitrating agent constituted by a mixture of bismuth nitrate / acetic anhydride in DCM with a series of substituted anilines under mild reflux. Several anilines having both activating and deactivating substituents in the ortho, meta and para positions were the substrate for the nitration reaction. Experimental conditions were performed in "one-pot" conditions before product purification. Bi(NO3)3•5H2O demonstrated to be effective and somehow regioselective when it came to the nitration of anilines in the ortho position. Although other products were also identified under these conditions, in most cases, the ortho derivative was the major or even the only product obtained with moderate to high yields in the range of 50% - 96%. Bi(NO3)3•5H2O is an efficient and safe nitrating agent since the use of concen-trated and corrosive acids like sulfuric and nitric is avoided; furthermore, bismuth nitrate is low-priced and no special care nor equipment is required.

Bonding performance and surface characterization of cold-bonded acetylated beech (Fagus sylvatica L.) laminated veneer lumber.

Acetylation of wood with acetic anhydride reduces the wood-moisture interaction, improves the dimensional stability and resistance against biodegradation. However, the adhesive bonding is affected by the modification, which is crucial to manufacture engineered wood products, such as laminated veneer lumber (LVL). In this study we report the bonding of 8-layered acetylated beech (Fagus sylvatica L.) LVL boards to 2-layered LVL beams. The beams were glued together at room temperature adding three common load-bearing construction adhesives: melamine-urea-formaldehyde (MUF), phenol-resorcinol-formaldehyde (PRF), and one-component polyurethane (PUR). The bonding performance was tested by assessing its dry and wet tensile shear strength(TSS) and wood failure percentage(WF). Also evaluated were the material's density and moisture content(MC). The surface was characterized prior to bonding by its pH, roughness, and contact angle(CA). The adhesive penetration was observed by fluorescence microscopy. Aside from MUF, applying PRF and PUR adhesives achieved good bonding performance on acetylated LVL and references. Acetylated LVL displayed a more hydrophobic behaviour, a higher pH, a somewhat smoother surface, and an increased density.

Electrically driven proton transfer promotes Brønsted acid catalysis by orders of magnitude.

Electric fields play a key role in enzymatic catalysis and can enhance reaction rates by 100,000-fold, but the same rate enhancements have yet to be achieved in thermochemical heterogeneous catalysis. In this work, we probe the influence of catalyst potential and interfacial electric fields on heterogeneous Brønsted acid catalysis. We observed that variations in applied potential of ~380 mV led to a 100,000-fold rate enhancement for 1-methylcyclopentanol dehydration, which was catalyzed by carbon-supported phosphotungstic acid. Mechanistic studies support a model in which the interfacial electrostatic potential drop drives quasi-equilibrated proton transfer to the adsorbed substrate prior to rate-limiting C-O bond cleavage. Large increases in rate with potential were also observed for the same reaction catalyzed by Ti/TiOyHx and for the Friedel Crafts acylation of anisole with acetic anhydride by carbon-supported phosphotungstic acid.

Copper catalysis the synthesis of functionalized glycine-based sulphonamides: In silico and in vitro antibacterial studies

The synthesis of functionalized glycine-based sulphonamides via copper catalyzed N-arylation reaction and the in silico, in vitro antibacterial studies is reported. The procedure involved the initial synthesis of substituted p-toluenesulphonamides and substituted benzenesulphonamides by the reaction of glycine with p-toluenesulphonyl chloride and benzenesulphonyl chloride respectively in aqueous basic medium. The syn[1]thesized compounds were acetylated by reacting them with acetic anhydride and sodium acetate followed by acylation and amidation to yield amidated p-toluenesulphonamides and benzenesulphonamides respectively. Copper catalyzed N-arylation of the amidated products with aryltriolborates resulted in the synthesis of benzene, and 2-chlorophenyl derivatives of the amidated products. The synthesized compounds were characterized using FTIR, 1HNMR and elemental analysis and the spectra were in agreement with the assigned structures. The in silico antibacterial studies revealed that the compounds possess significant antibacterial potency in the respective bacteria cells and could be further employed as potential anti-bacterial agents. The in vitro antimicrobial study revealed that most of the synthesized compounds possess antibacterial activities.

Assessment of the acetylation process of wheat straw pulp as sustainable rheological modifier for non-polar fluids

The main aim of this work was to study the role of the acetylation process of wheat straw pulp on its ability to rheologically modify two of the most important non-polar engineering fluid: bitumen and oil. Pulp was produced by a pilot-scale kraft pulping process from local wheat straw. Pulp was functionalized with acetic anhydride and sulfuric acid as a catalyst by modifying (temperature, pulp/acetic anhydride mass ratio, and reaction time. Further, chemical, morphological and thermal changes induced by the acetylation process were properly assessed. Acetylated wheat straw pulp dispersions in oil showed gel-like behaviour, with a mechanical spectrum characterized by higher values of the storage modulus (G′) and a minimum in the loss modulus (G″) at intermediate frequencies. The complex modulus (G*) for bitumen dispersions formulated with acetylated samples was up to 4 times higher than neat bitumen, and the phase angle (δ) indicated an enhancement in the elastic behavior parameters. The rheological response of these systems was associated with the microstructural network formed by pulp fibers and the balance between the physical and chemical changes of wheat straw fibers. According to the experimental results obtained, it can be concluded that acetylation is a relevant chemical treatment to modulate the rheological properties of wheat straw pulp dispersions in non-polar fluids, improving the compatibility between pulp fibers and these engineering fluids. Accordingly, this study provides valuable insights into the development of sustainable multiphasic materials (bitumen binders and semi-solid lubricants) for industrial applications.

Synthesis of Silicon and Germanium Oxide Nanostructures via Photonic Curing; a Facile Approach to Scale Up Fabrication.

Silicon and Germanium oxide (SiOx and GeOx) nanostructures are promising materials for energy storage applications due to their potentially high energy density, large lithiation capacity (~10X carbon), low toxicity, low cost, and high thermal stability. This work reports a unique approach to achieving controlled synthesis of SiOx and GeOx nanostructures via photonic curing. Unlike conventional methods like rapid thermal annealing, quenching during pulsed photonic curing occurs rapidly (sub-millisecond), allowing the trapping of metastable states to form unique phases and nanostructures. We explored the possible underlying mechanism of photonic curing by incorporating laws of photophysics, photochemistry, and simulated temperature profile of thin film. The results show that photonic curing of spray coated 0.1 M molarity Si and Ge Acetyl Acetate precursor solution, at total fluence 80 J cm-2 can yield GeOx and SiOx nanostructures. The as-synthesized nanostructures are ester functionalized due to photoinitiated chemical reactions in thin film during photonic curing. Results also showed that nanoparticle size changes from ~48 nm to ~11 nm if overall fluence is increased by increasing the number of pulses. These results are an important contribution towards large-scale synthesis of the Ge and Si oxide nanostructured materials which is necessary for next-generation energy storage devices.

Synthesis of New Glycosylamine Derivatives based on Carbohydrates

Background: Glycosylamine play an important role in living organisms. Most plants store their chemical resources in the form of inactive glycosides, which are broken down and con-verted into sugar in the body of herbivores by hydrolyzing enzymes. Glycosylamine are obtained from the secondary metabolism of plants and consist of two parts. One part of it contains sugar like glucose and is inactive in most substances, and has a good effect on the solubility of the glycosyla-mine derivatives and its absorption and even its transfer from one organ to another. The therapeutic effect is related to the second part, which is called aglycan (or aglucan). Glycosylamine derivatives form a large group of valuable medicinal substances, which at the same time include some of the most dangerous and toxic substances in nature. These substances are present in many groups of flowering plants. Glycosides are made in different ways in different metabolic pathways. These materials have a complex and special chemical structure and leave special effects on the human body. Glycosylamine derivatives are called O-glycosid, N-glycosid, S-glycosid in terms of atoms coupling to anomeric carbon. Carbohydrate esterification reaction to prepare new glycosylamine derivatives is one of the most important carbohydrate reactions. The anomeric position of carbohy-drates with strong leaving groups is very important for the preparation of glycosides. Preparation of glycosylamine derivatives based on acetylated carbohydrates is the main purpose of this article. Dif-ferent carbohydrates were acetylated under mild conditions and high yields. The anomeric position was deacetylated by a magnesium oxide heterogeneous catalyst in methanol solvent. In order to pre-pare new glycosides acetylated/ deacytylated carbohydrate reacted with N-Methyl-(naphtha-2-ylmethoxy)amine. The final product was identified by various spectroscopic methods. Methods: Anhydrous sodium acetate (4 g) and α-D-glucose (28 mg, 5 g) were mixed. The mixture was transferred to a 200 ml Round-bottom flask . Acetic acid (260 mg, 25 ml) was added to the reaction mixture. The reaction mixture was heated in a boiling water bath for 2 h until complete dissolution of the glucose. Then 100 ml of ice was added. After 1 hour, White crystals formed and were washed with cold water. And then 1 mol of glucose pentaacetate per 50 ml of methanol was dissolved by a magnetic stirrer. After thatMgO (0.2gr) was added to the reaction mixture. The re-action mixture was refluxed at room temperature within 4-5 hours. After 5 hours, the solvent was removed and separated by chromatography. It is then washed with hexane and crystallized by ether-hexane. And the final step reacted with N-Methyl- (naphtha-2-ylmethoxy) amine in order to prepare new glycosylamine derivatives. Results: Magnesium oxide in methanol solvent is one of the best effective catalysts in the deacetyla-tion of the anomer position of acetylated carbohydrates. It is done under ambient temperature and in very easy conditions and makes carbohydrates susceptible to extensive chemical reactions. One of these reactions is the formation of glycosides. Various carbohydrates are acetylated by acetic anhy-dride in the presence of sodium acetate, and the anomeric position is deacetylated by a heterogeneous catalyst. In order to prepare N-glycoside, the glycosides are reacted with N-alkoxy N-methylglycosyl amine. The final products are identified by various spectroscopic methods. Conclusion: Glucose, mannose, for example, were acetylated by acetic anhydride in the presence of sodium acetate. And the anomeric position of pentaacetate glucose was selectively deacetylated with magnesium oxide in a methanol solvent. Then, the reaction for the preparation of glycosylamine de-rivatives was carried out under very mild and easy conditions. The aminoglycosides synthesized in this article are used as raw materials for the synthesis of a wide range of antibacterials.

Harnessing Fermentation May Enhance the Performance of Biological Sulfate-Reducing Bioreactors.

Biological sulfate reduction (BSR) represents a promising strategy for bioremediation of sulfate-rich waste streams, yet the impact of metabolic interactions on performance is largely unexplored. Here, genome-resolved metagenomics was used to characterize 17 microbial communities in reactors treating synthetic sulfate-contaminated solutions. Reactors were supplemented with lactate or acetate and a small amount of fermentable substrate. Of the 163 genomes representing all the abundant bacteria, 130 encode 321 NiFe and FeFe hydrogenases and all genomes of the 22 sulfate-reducing microorganisms (SRM) encode genes for H2 uptake. We observed lactate oxidation solely in the first packed bed reactor zone, with propionate and acetate oxidation in the middle and predominantly acetate oxidation in the effluent zone. The energetics of these reactions are very different, yet sulfate reduction kinetics were unaffected by the type of electron donor available. We hypothesize that the comparable rates, despite the typically slow growth of SRM on acetate, are a result of the consumption of H2 generated by fermentation. This is supported by the sustained performance of a predominantly acetate-supplemented stirred tank reactor dominated by diverse fermentative bacteria encoding FeFe hydrogenase genes and SRM capable of acetate and hydrogen consumption and CO2 assimilation. Thus, addition of fermentable substrates to stimulate syntrophic relationships may improve the performance of BSR reactors supplemented with inexpensive acetate.

Pengembangan Acetylated Cellulose Nanofibers dari Microcrystalline Cellulose: Studi Perubahan Gugus Fungsi dan Indeks Kristalinitas melalui Asetilasi dan Nanofibrilasi

Cellulose nanofiber (CNF) has promising potential as a reinforcement in polymer matrix nanocomposites. CNF is polar or hydrophilic due to having many hydroxyl groups. When CNF particles are combined with a non-polar polymer matrix, the CNF is difficult to distribute evenly and tends to agglomerate due to differences in polarity so that the strengthening effect of CNF is limited. To overcome this problem, it is necessary to chemically modify the CNF surface. Acetylation is one of the most widely used CNF surface modification methods to increase the compatibility between a non-polar polymer matrix and CNF. Through the acetylation process, some of the hydroxyl groups of CNF are replaced with acetyl groups which are hydrophobic. Furthermore, the CNF resulting from the acetylation process is known as acetylated CNF (acetylated cellulose nanofibers or ACNF). The acetylation process is carried out by first mixing microcrystalline cellulose (MCC) particles into 75 mL of acetic anhydride solution. Next, the mixture was stirred using a high-speed blender for 30 minutes for the MCC nanofibrillation process to occur. In this research, the influence of acetylation and nanofibrillation processes on the characteristics of ACNF was studied through studying chemical structure changes using ATR-FTIR and crystallinity index using XRD. The results of the ATR-FTIR analysis show that there are 3 new peaks in the ACNF spectrum, namely at 1720, 1369 and 1203 cm-1, which proves that there is a change in the structure of cellulose after being given acetylation treatment. The results of XRD show that surface treatment of acetylation and nanofibrillation with a high-speed blender increases the ACNF crystallinity index value by 82.53%. Overall, the resulting ACNF has great potential as a reinforcement for polymer matrix nanocomposites.

Switching from wet to dry anaerobic digestion of food waste with different dilution times under no mechanical mixing condition

Previous research on anaerobic digestion of food waste has primarily focused on either wet or dry anaerobic digestion (AD), typically accompanied by continuous mechanical mixing. However, the necessary dilution rates and the extent of mixing required have yet to be addressed. In this study, we investigated switching from wet to dry AD of food waste without mechanical mixing, employing different dilution rates. Lab-scale anaerobic reactors were operated with dilution rates of 10, 5, and 2 times during Phases I (0–56 days), II (57–121 days), and III (122–209 days), respectively. The methane production rates were not significantly different (p > 0.05) across the dilution rates decreased from 10 to 2 times. Remarkably, the methane production in the anaerobic reactors exhibited fluctuations due to variations in feeding, with the methane production rate ranging from 2.0 to 2.7 g CH4-COD/(L d), without mechanical mixing, as the solids content transitioned from wet to near-dry digestion conditions (15 %, food waste). The distribution of sludge volatile solids concentrations remained uniform in the reactor, even at high solids concentrations of up to 15 %. A dynamic microbial community response to changes in dilution rates, with a shift from aceticlastic to hydrogenotrophic methanogenesis pathways. Syntrophic acetate oxidization bacteria (the genus Syner-01 (4.2–8.9 %) and f_Synergistaceae (3.6–4.2 %)) were highly enriched as switching from wet AD to dry AD. The study's findings provide crucial operational insights for anaerobic food waste treatment, potentially resulting in decreased water usage and operational costs, particularly in scenarios with low dilution rates and without mechanical mixing.

Crude oil sorption capacity of modified and unmodified biowaste

Contamination of water by crude oil is ubiquitous particularly in developing countries. The governments of affected countries raise a lot of concern because of the associated economic and environmental impacts which are not in tandem with the United Nations Sustainable Development Goals (SDGs), 6, 8, 11, 13 & 14. Remediation of crude oil-impacted water and soil become imperative. However, the exercise is expensive; hence the search for cheaper and local alternatives. In this study, unsegregated wood sawdust was collected from the various wood saw-dust dump sites within the main Timber shade in the vicinity of Udu Bridge, Udu LGA of Delta State, Nigeria. One half of the sample was chemically modified by acetylation using acetic anhydride while the other half wasn’t. They were characterized using Fourier Transformed Infra-Red Spectrophotometer (FTIR) and Scanning Electron Microscope coupled with Electron Dispersive X-ray (SEM/EDX) analyzer before employing them in the removal of the crude oil from the simulated crude oil spill- water media. The obtained results indicated that the modified sorbent (wood sawdust) sorbed more crude oil than the unmodified sorbent (wood sawdust). Experimental process control factors limited to time, sorbent dosage, particle size, was investigated using the modified sawdust. The modified sorbent gave maximum oil absorption capacity of 5.228 gg-1 for sorption time, 4.759 gg-1 for sorbent dosage and 5.838 gg-1 for particle size analyses. The study contributes to the knowledge of sorption studies using unsegregated wood sawdust for remediation of crude oil-contaminated media.

Anaerobic methane oxidation is quantitatively important in deeper peat layers of boreal peatlands: Evidence from anaerobic incubations, in situ stable isotopes depth profiles, and microbial communities

Boreal peatlands store most of their carbon in layers deeper than 0.5 m under anaerobic conditions, where carbon dioxide and methane are produced as terminal products of organic matter degradation. Since the global warming potential of methane is much greater than that of carbon dioxide, the balance between the production rates of these gases is important for future climate predictions. Herein, we aimed to understand whether anaerobic methane oxidation (AMO) could explain the high CO2/CH4 anaerobic production ratios that are widely observed for the deeper peat layers of boreal peatlands. Furthermore, we quantified the metabolic pathways of methanogenesis to examine whether hydrogenotrophic methanogenesis is a dominant methane production pathway for the presumably recalcitrant deeper peat. To assess the CH4 cycling in deeper peat, we combined laboratory anaerobic incubations with a pathway-specific inhibitor, in situ depth patterns of stable isotopes in CH4, and 16S rRNA gene amplicon sequencing for three representative boreal peatlands in Western Siberia. We found up to a 69 % reduction in CH4 production due to AMO, which largely explained the high CO2/CH4 anaerobic production ratios and the in situ depth-related patterns of δ13C and δD in methane. The absence of acetate accumulation after inhibiting acetotrophic methanogenesis and the presence of sulfate- and nitrate-reducing anaerobic acetate oxidizers in the deeper peat indicated that these microorganisms use SO42− and NO3− as electron acceptors. Acetotrophic methanogenesis dominated net CH4 production in the deeper peat, accounting for 81 ± 13 %. Overall, anaerobic oxidation is quantitatively important for the methane cycle in the deeper layers of boreal peatlands, affecting both methane and its main precursor concentrations.