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A photo-reversible and reusable polymer adhesive was designed and synthesized from bio-resources. Six unique monomers were evaluated via structure–property analysis, and the best polymer adhesive performance was optimized using statistical methods.

The over-use of synthetic nitrogen (N) fertilisers for crop production can cause environmental pollution through leaching and gaseous losses, resulting in low N use efficiency (NUE).

In this study, we observed the effect of a newly developed slow release brown coal-urea (BCU) fertilizer on the greenhouse gas emissions, plant growth, yield, and nitrogen use efficiency (NUE) of sweet corn grown under field conditions, as compared with conventional urea fertilizer. The soil was treated with urea and BCU as a N fertilizer at a rate of 90 or 180 kg N ha-1 at sowing and incorporated. Seventeen N2O and 10 NH3 gas samples were collected to determine the gaseous emissions of fertilizer-N. The addition of BCU considerably enhanced the availability and uptake of fertilizer-N to sweet corn by decreasing greenhouse gas emissions by 59% as N2O and by 29% as NH3 compared to commercial urea. Slow release BCU fertilizers enhanced NUE and cob yield by 32 and 24%, respectively, over urea. Furthermore, the soil incorporation of BCU fertilizer resulted in a significant increase in the organic carbon content of soil at harvest. Therefore, the application of slow release BCU fertilizer could be a more economic, profitable, and environmentally friendly N fertilizer alternative over the use of conventional urea.

The present study aims to recover value-added products from fresh pineapple processing wastes in an integrated biorefinery. Bromelain, a therapeutic protease, was extracted from pineapple by-products via an aqueous, low-temperature process. Bromelain-free biomass was rich in insoluble fibre and was further fractionated into hemicellulose, cellulose and lignin. The highest content of active bromelain was obtained from pineapple core waste of the different varieties namely, Smooth Cayenne (~ 1.9 ± 0.05 CDU/mg), Giant Kew (1.6 ± 0.05 CDU/mg) and MD2 (1.5 ± 0.1 CDU/mg). The activity of extracted bromelain was close to commercial stem bromelain (2.2 ± 0.1 CDU/mg, % purity of 95–96%). The fractionation of fibrous residue (97.2 ± 0.5 g/100 g of dry mass) was optimised, and maximum yield of hemicellulose (97.5 ± 0.2%) was obtained with 5% (w/v) alkali at the end of 1.5 h. The hemicellulose and cellulose-rich residues were further valorised into xylooligosaccharides (26.1 ± 0.4 g/100 g of hemicellulose) and glucose (85.3 ± 1.7 g/100 g of cellulose-rich residue), respectively. From one ton of fresh pineapple processing waste, ~ 1 kg bromelain, ~ 24 kg xylooligosaccharides, ~ 88 kg glucose and ~ 68 kg residual hemicellulose could be obtained. The proposed biorefinery concept not only addresses the environmental issues but also creates an opportunity to generate wealth in the form of products required for food and pharmaceutical industries from processing waste. As demand for more natural products is rising and consumers choice are prompted by healthy foods, conversion of pineapple waste into above mentioned valuable products creates a niche in food and therapeutics industry. Schematic for extraction of bromelain coupled with co-production of xylooligosaccharides and glucose from pineapple waste.

An alkali-mediated hydrothermal approach was optimized for partial extraction of high-purity hemicellulose (xylan) from a timber waste product (unbleached eucalyptus sawdust). The extraction process was: a) extractives removal using sequential solvent extraction; b) alkali-mediated hydrothermal extraction of hemicellulose; and c) purification of the isolated hemicellulose fraction. Biomass was extracted in an autoclave at a fixed temperature of 121 °C while varying the extraction time (1 h to 2.5 h) and alkali concentration (10%, 15%, and 20% w/v). Using this simple approach, high purity polymeric hemicellulose with molecular mass (21 to 30 kDa) was recovered in yields of 35 to 37%. The isolated hemicellulose can be chemically transformed into high-value commercial products such as prebiotics (xylooligosaccharides), surfactants, hydrogels, and food packaging materials. The purified residue can be utilized in existing kraft pulping processes. The integration of hemicellulose extraction into existing pulping process represents additional valorization of timber resources.

The present study is first of its kind that focuses upon the extraction of bromelain from pineapple core waste and stabilising it as insoluble cross-linked aggregates. The influence of process variables such as the choice of precipitant, type of cross-linker, concentration of cross-linker and the reaction time for cross-linking step was investigated upon the activity recovery of bromelain cross-linked aggregates. The optimization of this biocatalyst preparation specifically recovered 87% of the enzymatic activity available in pineapple core waste by ammonium sulphate (60%, w/v) precipitation followed by cross-linking for 4 h with 80 mM glutaraldehyde. Cross-linked bromelain aggregates were thermally more stable and exhibited higher pH stability in comparison to free bromelain. The cross-linked bromelain aggregates exhibited higher operational stability in different organic solvents at 4 °C. The highest operational stability (% stability given in parenthesis) was observed in acetone (100%) followed by hexane (53.6%), ethyl acetate (39.6%), ethanol (32.5%) and chloroform (14.9%). The kinetic studies revealed higher Km value (5.45 mM) after the formation of cross-linked bromelain aggregates as compared to free bromelain (5.04 mM) with almost similar Vmax values. Cross-linked bromelain aggregates also showed significant reusability characteristics with an activity retention of >85% after 5-time cycles. Such recyclability of bromelain cross-linked aggregates could lead to potential industrial applications in both food and non-food sector. In addition, the present extraction method avoids costs related to purification and expensive immobilization carriers.

Sewage sludge, often referred to as biosolids, is generated in large quantities by wastewater treatment plants. It contains macro- and micronutrients which are essential for plant growth and so represents a valuable agricultural resource. Prior to land application, pathogens are carefully monitored to reduce the risk of crop and soil contamination however to date there has been limited investigation of agriculturally beneficial bacteria indigenous to the biosolids. This study investigated shifts in the composition of the bacterial community alongside the physicochemical properties of biosolids of increasing age, from freshly dewatered to those stockpiled for approximately four years. With stockpiling, there was a significant increase in ammonium content, ranging from 801 mg/kg in the fresh biosolids to 8178 mg/kg in the stockpiled biosolids and a corresponding increase in pH ranging from 6.93 to 8.21. We detected a ten-fold increase in Firmicutes, from 4% relative abundance in the fresh biosolids compared to 40% in the older, stockpiled biosolids. Plant growth promoting bacteria (PGPB) of the Proteobacteria family, particularly of the Devosia and Bradyrhizobium genera were identified in the freshly dewatered and the older, stockpiled biosolids. Land application of the biosolids studied here could reduce fertiliser costs, provide a means of pH correction to acidic soils and a potential source of bacteria beneficial for crop growth.

Inhaled essential oils (EOs) are bioavailable to the brain and are consistently reported to promote relaxation effects. Their mechanisms of action are however not well understood. The aim of this investigation was to assess the neuroactivity of EOs based on their (i) binding interactions to neurotransmitter receptors and (ii) bioelectrical activities in the brain as measured by electroencephalography (EEG). These EO properties were compared to those of reference pharmaceutical compounds with effects also measured by EEG. Relative receptor binding efficacies of 10 reference compounds, 180 EOs, and 9 EO extracts with 7 different neurotransmitter receptors were calculated using

We introduce a recyclable and efficient enzymatic process by integration of microwave (MW) pretreatment followed by magnetic nanobiocatalysis for the green and sustainable oilseed biorefinery. The ...

The fluid loss test has been used by geotechnical engineers for rapid evaluation of the hydraulic barrier properties of bentonites. In this study, a modified fluid loss test, along with viscometric and electrophoretic mobility measurements, was used to assess the colloidal interactions of three powdered sodium bentonites with saline leachates, namely 0–2 N solutions of NaCl and CaCl2. The results indicate that the fluid loss test provides robust and reliable information on the water retention of bentonite; moreover, it gives information on the aggregate structure, size, and settling of bentonite flocs and on the high-salt stabilization phenomena (packing and densification of clay aggregates) in saline leachates. Quantifying the water retention characteristics, along with the colloidal (i.e., flocculation) behaviour, using the fluid loss test, provides detailed understanding of barrier properties of bentonites important for various applications (e.g., barrier systems, dewatering).

Pineapple peel waste was utilized as an unexplored source of hemicellulose (31.8 ± 1.9%) for value addition. Hemicellulose was extracted by an alkali-based method, where the peels were incubated at different alkali concentrations (5%, 10% and 15% w/v) at temperatures ranging from 35 °C to a maximum of 65 °C for a fixed period of 16 h. A maximum recovery of hemicellulose (95.9 ± 2.0%) was observed after incubating extractive-free pineapple peels in 15% (w/v) alkali solution for 16 h at 45 °C. Higher incubation temperatures (65 °C) for 16 h, resulted in a lower yield of hemicellulose (81.7 ± 3.7%) which can be attributed to the disintegration of the hemicellulose structure due to large severity factor (temperature–time combination). With low severity factor, it was noted that higher yields (96.6 ± 0.3%) were obtained 65 °C, 4 h). Hydrothermal-assisted alkali extraction was also evaluated for maximizing the recovery of pineapple peel hemicellulose. The maximum relative recovery of ˜87.6% was obtained with 10% (w/v) alkali at the end of 1.5 h of hydrothermal pretreatment (121 °C and 15 psi pressure). The hemicellulose extracted by hydrothermal-assisted alkali pretreatment was enzymatically hydrolyzed to produce XOS and the process was optimized in terms of enzyme dose (U), temperature (°C), pH and time (h). Direct hydrolysis of pineapple peels with dilute nitric acid produced xylose-rich liquor (˜91% xylose yield) at 0.5% nitric acid, reaction time of 1 h and solid–liquid ratio of 1:20. The xylose-rich liquor could be converted to potential chemicals such as xylitol.

Although the waste pomegranate peel (WPP) is a popular antioxidant source, pomegranate antioxidant extracts available in the market lack key antioxidant “punicalagin”. Commercial production of pomegranate antioxidant extracts employ energy demanding drying of WPP followed by long hour extraction (detrimental to punicalagin) with organic solvents hazardous to the environment and human health that require stringent solvent recovery and disposal. Therefore, a fast and eco-friendly method based on aqueous ball milling (at pH 7 and 40 °C) without using hazardous reagent was developed to extract punicalagin enriched phenolics directly from fresh WPP. The systematic study of the combinations of ball milling time and liquid: solid ratio led to the highest recovery of phenolics (11–11.7 g 100 g−1 DW of WPP of wonderful and Ruby cultivar) containing 8.6–9.5 g punicalagin with highest antioxidant activity after 10 min ball milling with aqueous buffer at 15 mL g−1 liquid:solid ratio. The ball milling at these conditions using conventional organic solvents (methanol, ethanol, acetone, and ethyl acetate) yielded lower recoveries of total phenolics (4–11 g 100 g−1 DW of WPP) containing only 0.6–2.6 g punicalagin. The aqueous ball milling was also more rapid and efficient for the extraction of total phenolics and punicalagin than the ultrasound-assisted and Soxhlet extraction with methanol and aqueous buffer. Remarkably, the punicalagin content of the phenolic extract (70% w/w) obtained by aqueous ball milling is significantly higher compared to the punicalagin content (10–30% w/w) of commercially available pomegranate phenolic extracts. This extract also showed excellent storage stability as evident from no change in its punicalagin content even after 36 days of storage at 20 °C.

We demonstrate a novel recyclable enzymatic approach of extraction of pectin and punicalagin rich phenolics from the waste pomegranate peels (WPP) using the magnetic nanobiocatalyst technology. First, the cellulase was cross-linked with the iron oxide magnetic nanoparticles using glutaraldehyde to prepare the magnetic nanobiocatalyst which was characterized using FT-IR, FE-SEM, and TEM. Then, ultrasonically pre-treated WPP were hydrolyzed with the magnetic nanobiocatalyst at cellulase loading of 75 U/g of peel powder, pH 6 and 50 °C for 5 h to obtain maximum recovery of pectin (19.4%) and total phenolics (8.8%) comparable to non-green conventional methods. The magnetic nanobiocatalyst was easily recovered by the application of a magnetic field and recycled for five cycles with no change in pectin and total phenolics yields and cellulase activity. In addition, IR, 1H NMR, and TGA analysis showed that the chemical nature of pectin was the same in each cycle. The uronic acid content (72–74%), degree of esterification (62–64%), molecular weight (140–143 kDa) and polydispersity (1.5–1.6) of pectin from each cycle were also in the similar range. The total phenolics obtained in each cycle were rich in punicalagin (75–78% of total phenolics) with similar content of 6.42–6.65 g/100 g WPP. These results indicated the excellent stability and reusability of the cellulase magnetic nanobiocatalyst for the recovery of WPP pectin and phenolics of consistent yield and chemical nature/composition.

Increasing crop yield and fertiliser nitrogen (N)-use efficiency is important for productive agricultural systems with a reduced environmental footprint. The aim of this study was to assess the effect of slow release brown coal-urea (BCU) fertiliser on the gaseous N losses, biomass yield and N uptake by silver beet (Beta vulgaris L.) compared to commercial urea. Two soils were amended with urea, BCU 1 (22% N) or BCU 2 (17% N) as N-fertiliser at the rate of 50 or 100 kg N ha−1. Five gas sampling periods were undertaken to measure the loss of N as N2O and NH3. After 10 weeks, biomass, N concentration, and N uptake of silver beet, and mineral and mineralisable N of post-harvest soil were measured. BCU substantially increased fertiliser N availability and uptake by silver beet, reduced N2O emission by 29% and NH3 emission by 36% compared to urea alone, irrespective of soil type. Compared to urea, BCU blends increased biomass yield by 27% and 23% in a Tenosol and Dermosol soil, respectively. In addition, application of BCU fertiliser substantially enhanced the potentially mineralisable N and organic carbon content of soil. These results provide evidence that granulation of urea with brown coal (BC) can increase silver beet N-use efficiency and yield in different soil types, and more work is now required to validate this technology for other crops.

Carboxylated nanocellulose superabsorbent polymers (SAP) can be used to increase soil water retention in agriculture. The benefits investigated are influenced by the superabsorbent structure, composition and application rate. In this study, TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl)-oxidised nanocellulose superabsorbents were prepared using three different drying techniques: freeze-dried, and oven-dried at low and high temperatures. The swelling capacity in soil water extracts was measured and compared to deionised water. Soil was amended with different application rates of these superabsorbents to evaluate the effects on water retention, microbial community and their biodegradation. The absorption performance of nanocellulose superabsorbents is affected by the concentration and type of salts in the soil water extracts. Oven-dried at 50°C SAP presents the highest ionic sensitivity attributed to its large number of accessible carboxylate groups. The water retention of the soil treatments increases with increasing application rate. Soil treated with the freeze-dried superabsorbent shows the highest water retention, whereas those amended with the 50°C oven-dried SAP remain moist the longest. The biodegradation rate of these materials depends on the application rate and nutrient availability. Carboxylated nanocellulose superabsorbents emerge as high-performance biodegradable materials for agricultural use, able to replace the current non-biodegradable petrochemical-based superabsorbents.

Hypothesis: Carboxylated nanocellulose gels and superabsorbents (SAPs) can be engineered by ion exchange of TEMPO treated cellulose fibers with different cations prior to shearing, thus creating a nanofibrous network ionically cross-linked. The structure and properties of these materials are highly influenced by the type counter-ion used as it controls both the degree of fibrillation and crosslinking. Experiments: Functionalised nanocellulose SAPs were made using TEMPO-mediated oxidation followed by ion-exchange before fibrillation into a hydrogel and freeze-drying. Seven different cations were tested: 4 of valency 1 (H, Na, K, NH4), and 3 of valency 2 (Ca, Mg, and Zn). The effect of the counter-ion on the gelation mechanism and the superabsorbent performance was evaluated. The SAP absorption capacity in deionised water was related to the superabsorbent structure and morphology. Findings: The gel stability of nanocellulose superabsorbents is governed by the counter-ion type and valency. The viscoelastic properties of all nanocellulose hydrogels are controlled by its elastic regime, that is storage modulus (G′) > loss modulus (G″). The type of cation dictates the rheology of these gels by altering the fibrillation efficiency due to the extent of ionic cross-links occurring before and after fibrillation. The driving force for gelation in monovalent gels is due to the coupling of nanofibrils by physical interactions, creating an electrostatic stabilisation of the ionised COO– groups at high shear forces. Cation – carboxylate interactions dominate the gelation in divalent gels by supressing the repulsive charges generated by the COO– and also creating interfibril connections via ionic-crosslinks, as confirmed by the zeta potentials. The superabsorption performance is dominated by the counter-ion and is in the order of: NH4+ > K+ > Na+ > Mg2+ > Zn2+ > Ca2+. NH4+-SAPs present the slowest kinetics and the highest absorption capacity. Its high pore area, which extends the number of accessible carboxyl groups that participates in hydrogen bonding with water, is responsible for this behaviour. Nanocellulose SAPs are attractive renewable materials, suited for many applications, including as nutrient cation carriers in agriculture.

Background Fruit and vegetable processing industries account for the largest segment of food waste which is produced worldwide. The disposal of this waste requires a huge capital investment, majority of which is the transportation costs. This results in dumping and burning of these wastes in open fields. Scope and approach In this review, we have focussed on the valorisation schemes to extract valuable biomolecules from pineapple on-farm and processing waste for food and therapeutics applications. Biorefinery approach has been highlighted for sustainable production of value added products. Key findings and conclusion The high content of carbohydrate (55%) in pineapple waste makes it an appropriate substrate for the production of valuable chemicals such as xylitol, xylooligosaccharides, lactic acid, succinic acid and others, which have potential application in the food industry. The enzyme, bromelain, which is present in pineapple, has potential for application in therapeutics as well as in the food industry. Such utilisation of waste could prove to be a better alternative in the mitigation of environmental problems and also to propose a novel method to produce valuable chemicals. Despite the opportunities, there are challenges in the valorisation of this waste, largely due to the poor understanding of its nutritional and economic value, gap in close-linked markets, logistics issues for plant scale-up. Since most of the research is limited to lab-scale studies, additional research is required to evaluate techno-economic feasibility of the processes involved in the bio-refinery with minimum environmental impact for effective transition to circular economy.

Two Victorian brown coal samples, a run-of-mine Loy Yang coal (LY) and a Loy Yang light lithotype (LL), were subjected to pyrolysis at 420–460 °C and 330–460 °C, respectively, under a continuous nitrogen flow. The process produced condensed products in two phases, oil and aqueous, as well as solid residue and gaseous products. An increase in the condensed product yields with increasing temperature was observed for both coals, with LL achieving higher yield than LY at a given temperature (e.g. 26.3 wt% vs 19.5 wt% at 460 °C). The condensed products were characterized by 1H and 13C NMR as well as GC–MS. Abundant triterpenoid polycyclics and aliphatic hydrocarbons were found in the oils from both coals produced at lower temperatures, whilst the yield of aromatics significantly increased with increasing pyrolysis temperature. Analyses of the solid residues by FTIR, solid state 13C NMR and flash pyrolysis GC–MS (Py-GC–MS) also revealed an increasing aromaticity of the residues at higher temperatures. Py-GC–MS analysis identified compound groups released by flash pyrolysis at 650 °C and the results were found to correspond to those of GC–MS for the oil.

This work demonstrates the complete utilization of waste pomegranate peels (WPP) to produce pectin, punicalagin rich phenolics, and a hard carbon electrode. The high yields of pectin (24.8%) and phenolics (11.9%) were obtained at optimal ultrasound (20 min ultrasound time, 15 mL g–1 liquid:solid ratio) and cellulase treatment (55 U g–1 cellulase dosage, 4 h treatment time) of WPP. The IR, 1H NMR, and TGA analysis showed that the recovered pectin was similar to commercial pectin. The recovered pectin had a 68.5% degree of esterification, 146.5 kDa molecular weight, and 72% galacturonic acid content. A high content of valuable punicalagin (71.2% of total phenolics) occurred in the recovered phenolics. The WPP leftover (after pectin and phenolics recovery) was carbonized via pyrolysis and then impregnated with potassium hydroxide and heated in an inert atmosphere to obtain hard carbon (HC) to be employed as an electrode in electrochemical cells. The Raman spectroscopy, X-ray crystallography, and CHN analysis...

An integrated biorefinery, incorporating hydrothermal processing of waste pomegranate peels (WPP), was proposed for the acid and organic solvent-free simultaneous recovery of pectin and phenolics with bioethanol production. The hydrothermal treatment (HT) was optimized using Box-Behnken design and the maximum recovery of pectin (18.8–20.9%) and phenolics (10.6–11.8%) were obtained by hydrothermal treatment at 115 °C for 40 min with a liquid-solid ratio of 10. The WPP pectin was characterized by IR, 1H NMR, and TGA which showed close similarity to commercial pectin. Depending on WPP cultivar type the degree of esterification, galacturonic acid content and molecular weight of pectin were in the range of 68–74%, 71–72%, and 131,137–141,538 Da, respectively. The recovered phenolics contained 57–60% punicalagin. Enzyme digestibility of WPP improved using HT with 177 g glucose produced per kg dry mass which was fermented to obtain 80 g ethanol with 88% of theoretical yield.

This study evaluated costs and profitability associated with mango processing waste biorefinery plant with the goal of generating wealth from waste. Three pathways were evaluated (i) Only Pectin recovery (PEP) (ii) Pectin and Seed Oil recovery (PSEP), and (iii) whole biorefinery with multiple products (WMB). A plant capacity of 10 tons/h was considered as a base case for analysis. Effect of biomass feed composition on product yields were also reported in this study. The PSEP was found to be the best alternative for mango waste utilization. The NPV, IRR and PEP were $41 million, 34% and 2.4 years, respectively. In case of PEP and WMB, NPVs were $14.2 and $43.2 million; IRRs were 20% and 26%, and PBP were 4.2 and 3.4 years, respectively. Sensitivity analysis showed that plant capacity, plant operating days, and raw material composition were most important factors that influenced plant economics. Selling price of main product i.e. pectin had a major influence on plant economics. The effect of raw material price fluctuation however, did not influence plant economics significantly.

An environment-friendly hydrothermal process was developed to extract pectin from a horticultural waste, namely mango peels, at a reasonable temperature and pressure. High average yields of pectin (15.7%, 27.2%) were obtained from the two mango cultivars namely, Calypso (Australian) and Totapuri (Indian). The physico-chemical characteristics were determined in terms of the degree of esterification (77–89%), molecular weights (Mw) (49,742–49,862 Da), FTIR and gelling tests. The spent liquor was hydrolysed to recover the specific polyphenols and sugars. The polyphenols in the hydrolysed liquid were quantified as gallic acid (525.1–1405.6 mg/l), mangiferin (7.8–162.2 mg/l), quercetin (40.6–49.2 mg/l) and ellagic acid (38.8–69.3 mg/l). The solid residue obtained as a solid co-product after pectin extraction was found to be rich in cellulose (38%) and lignin (16%). In this paper, an attempt has been made to address the challenges of the extraction of pectin from mango peels, in a conventional process. It was demonstrated that mango peels may be a promising unconventional source for recovery of food-grade quality pectin. Considerable efforts, which were earlier expended in the processing, were reduced when recovery of other food-grade co-products was integrated with the process of hydrocolloid extraction.

Composts are being increasingly used as an alternative to mineral fertilisers in production agriculture. However, some farmers are reluctant to utilise compost due to lack of consistent information regarding agricultural productivity and management. Here we explore the changes in soil chemistry, plant biomass production and nutrition during an 18 month transition period from mineral to compost fertiliser use. This was undertaken on plots excluding stock on two dairy farms in southeastern Australia. Biomass was not affected by compost application, demonstrating that productivity and nutrition were maintained during early stage transition. Soil chemical properties, including available nitrogen species, were influenced by compost, but changes fluctuated over the transition phase. Impacts of management practices, season and soil chemical influences on biomass production were explored using multivariate techniques. This analysis revealed that season and inherent soil chemical properties had the greatest influence on pasture biomass during early stage transition. Results are discussed in the context of a transition to compost-based nutrient management of grazed dairy pastures.

Xylooligosaccharides (XOS) are naturally occurring high value biochemicals with potential applications in the food, pharmaceutical and fine chemical industries. They are typically produced and purified from a variety of biomass resources in expensive and inefficient multi-step batch processes, and this high cost of production is a significant barrier to their commercial adoption. A flow-type microreactor was used to intensify and increase the efficiency of enzymatic XOS production from beechwood xylan. The xylan hydrolysis performance was compared with the same reaction performed under typical batch conditions. Over 80 g XOS per 100 g xylan was obtained in less than one minute of residence time at the optimum conditions tested in continuous flow experiments. The enzymatic xylan hydrolysis performance was improved and xylan to XOS conversion was three times higher under optimised flow conditions compared to a conventional batch process.

Essential oils (EOs) absorbed via inhalation are consistently reported to produce anxiolytic effects. The underlying neurochemical mechanisms, however, are not well understood. High concentrations of ascorbate in the human brain (~10 mM in neurons) implicates this compound as a key signaling molecule and regulator of oxidative stress. In this study, we demonstrate the significant in vitro capacity of ascorbate to produce H2O2 in the presence of oxygen at physiological pH values, peaking at ~400 μM for ascorbate levels of 1.0 mg/mL (5.6 mM). In comparison, individual EOs and selected neurotransmitters at similar concentrations produced

Lignocellulosic biomass is a rich source of cellulose and one of the most promising raw materials for the production of biofuels and other value added chemicals. However, its high lignin content and complex cellular structure represent a significant processing challenge. In this work, the effect of pretreatment using [EMIM][Ac] was studied at various process parameters in order to develop a cost-effective process. In order to minimize the loss of sugars in this process bulk of the solids, comprising both regenerated cellulose and undissolved particles were subjected to the enzymatic hydrolysis. Up to 96% enzymatic digestibility was achieved, even with relatively coarse particle sizes (0.6–1.0 mm range), at 10% biomass loading. The enhanced digestibility of CS is attributed to reduction in lignin content, crystallinity of the cellulose coupled with an increase in surface area.

Lignin has been widely studied as a sustainable source of renewable materials, particularly aromatic feedstock chemicals, which are in great and increasing need in the world. Lignin oxidation and depolymerization presents a promising approach to functionalized phenolic products. In this work, a novel oxidative degradation of lignin using a formate ionic liquid was investigated resulting in ethyl acetate soluble and also water-soluble depolymerized lignin products. The β-O-4 bonds in lignin were oxidized and then depolymerized by a recyclable ionic liquid, 2-hydroxy ethylammonium formate. 2-Hydroxy ethylammonium formate, which could dissolve lignin acting as a solvent, was found to also catalyze the depolymerization of the oxidized lignin. The lignin depolymerization products were characterized.

Accurate assessment of environmental variables is vital to understanding the global issues of land-use change and climate change, but is hindered by their high spatial and temporal heterogeneity. Extensive surveys are needed to model such large-scale problems, with their success dependent on adequate sampling protocols. We present a robust method for designing efficient sampling protocols for environmental variables. The SIMAP method involves the following steps: 1) Selecting sites that cover a representative range of spatial variability, 2) Intensive and spatially-accurate surveys within sites, 3) construction of continuous Maps that replicate the spatial and statistical variation of the surveys, 4) Accuracy simulations based on sampling of these maps and 5) determining a sampling Protocol for subsequent broader surveys. To illustrate the method, we used estimation of soil C stocks in mixed-species tree plantings and pastures to estimate carbon sequestration following reforestation. Soil C was surveyed intensively from these two land uses at several farms that covered a large rainfall gradient to provide contrasting datasets. In this example, sampling simulations showed that a systematic design generally required one less sample than a restricted-random design to achieve the same accuracy, while a simple-random design required substantially more samples. We found taking a minimum of 30 soil samples was needed for both bulk density and C concentration to accurately estimate soil C content within a 1-ha plot in a pasture or tree planting, which suggests many previous surveys of soil C were sampled inadequately. The SIMAP method could be readily applied to a range of abiotic and biotic variables, with the construction of maps allowing most sampling intensities and designs to be tested. Adequate sampling intensities differ widely among environmental variables, so the SIMAP method enables researchers to determine which variables require more investment. For many variables, costs may be minimised while maintaining a high accuracy of the sampling design via bulking of well-mixed samples prior to analysis.

The reactivity pattern of the MnO2 catalyst in the selective aerobic oxidation of benzyl alcohol is assessed by density functional theory (DFT) analysis of adsorption energies and activation barriers on a model Mn4O8 cluster. DFT calculations predict high reactivity of defective Mn(IV) sites ruling a surface redox mechanism, L-H type, involving gas-phase oxygen. Bare and promoted (i.e., CeOx and FeOx) MnOx materials with high surface exposure of Mn(IV) sites were synthesized to assess kinetic and mechanistic issues of the selective aerobic oxidation of benzyl alcohol on real catalysts (T, 333–363 K). According to DFT predictions, the experimental study shows: i) comparable activity of bare and promoted catalysts due to surface Mn(IV) sites; ii) the catalytic role of oxygen-atoms in the neighboring of active Mn(IV) sites; and iii) a 0th-order dependence on alcohol concentration, diagnostic of remarkable influence of adsorption phenomena on the reactivity pattern. Evidences of catalyst deactivation due to the over-oxidation of benzyl alcohol to benzoic acid, acting as poison of the active sites, are discussed.

Two cyclic organic carbonates (COC), propylene carbonate (PC) and glycerol carbonate (GC), were investigated as saline-resistant modifying agents of Na+-montmorillonite using X-ray diffraction (XRD) and Fourier transform infrared (FTIR). PC has been studied previously and has been used as an effective amendment material of Na+-bentonite for saline applications. In this research GC is proposed as a more effective modifying agent for containing hyper saline leachates. Na+-montmorillonite was reacted with up to 1 N sodium chloride (NaCl) and calcium chloride (CaCl2) salt solutions to assess changes in the interlayer spacing (i.e., d-value of the 001 reflection in XRD traces) due to osmotic desiccation, as well as to investigate the mechanism and strength of bonding between GC/PC and Na+-montmorillonite by FTIR. GC/Na+-montmorillonite was strongly resistant against strongly saline sodic salt solution compared to PC/Na+-montmorillonite. CaCl2 solution had a more detrimental effect on COC modified Na+-montmorillonite, however, GC/Na+-montmorillonite appeared to retain more intercalated COC than PC/Na+-montmorillonite when leached by strong calcic salt solutions.

Lignin, considered as the second most abundant resource of aromatic chemicals in nature, has attracted a great deal of attention in academia and industry. Recently, numerous investigations have been carried out to consider the production of aromatic chemicals with high value, sourced from lignin. Among all these methods, oxidative treatments of the lignin show a promising way to generate highly functionalised monomeric or oligomeric chemicals, which can be further applied in chemical industries. Moreover, ionic liquids, known as salts with melting point below 100 °C, have also been introduced into oxidative lignin depolymerisation as these are known to disrupt the lignocellulose structure as well as partially dissolving the lignin. Herein, we reviewed various significant pathways of catalytic lignin oxidation and also discussed strengths and weaknesses between different lignin oxidation routes reported in the recent literature. Several innovative strategies for oxidative lignin depolymerisation in ionic liquid are also discussed, along with some recommendations and pathways in the field of catalytic lignin oxidation and depolymerisation involving ionic liquids.

The effect of adding glycerol carbonate (GC) or propylene carbonate (PC) to sodium (Na)-bentonite on the hydraulic performance of geosynthetic clay liners (GCLs) under hypersaline conditions is examined. Fluid loss (FL), swell index (SI) and solution retention capacity (SRC) measurements were carried out to compare the potential hydraulic performance of these two cyclic organic carbonates (COCs) as bentonite modifiers. A modified FL test enabled quantitative measurement of both the water retention characteristics of untreated and COC modified bentonites as well as calculation of hydraulic conductivity values. Tests under aggressively saline conditions (ionic strength, I ≥ 1 M of NaCl and ≥3 M of CaCl2) showed that at a mass ratio of 1:1 (GC to bentonite), the FL of a GC-Na-bentonite was ≈40–104 mL in NaCl and ≈61–91 mL in CaCl2. This was about 10–20 mL and 70–200 mL, respectively, lower than that of a comparable PC-Na-bentonite (1:1 PC to bentonite) and untreated Na-bentonite. Greater swelling (SI) and greater solution retention capacity (SRC) was observed for the GC treated Na-bentonite compared to untreated Na-bentonite in all salt solutions, and for PC-Na-bentonite at high ionic strength of both NaCl and CaCl2 solutions, demonstrating the superior hydraulic barrier performance of COC-bentonites under severely saline conditions. Experiments conducted in flexible-wall permeameters with I = 3 M CaCl2 showed approximately one order of magnitude lower (∼10−11 m/s vs ∼1.9 × 10−10 m/s) hydraulic conductivity of GC treated bentonite cake compared to the k value of the untreated Na-bentonite cake. Calculated hydraulic conductivity from fluid loss tests estimated the measured values in a conservative way (overestimation).

Valorization of mango peels to recover pectin has the potential to increase the economic viability of a biorefinery utilizing this waste resource. Replacement of conventional mineral acids used for extraction of pectin with natural food grade acids would assist in making the process more environmentally friendly and safe for food applications. In this work, we have evaluated the effect of a natural acidifying agent, lemon juice, in combination with sonication, on pectin extraction. Sonication was used for 20 min at 80 °C, compared to the conventional process which involves boiling for 150 min, thus improving the energy cost of the process considerably. More than 26%w/w of the mass of dried mango peel was extracted as pectin; this was classified as low methoxyl pectin (degree of esterification ≤ 50%). Pectin having this DE is of importance in low calorie food products as a nutraceutical additive.

Five-membered cyclic organic carbonates (COC) are of interest for their ability to modify the surface properties of smectites and enhance the hydraulic resistance of bentonites to saline leachates. The mechanism of interaction of glycerol carbonate (GC) and several other hydroxyl containing cyclic organic carbonates (generally having progressively greater molecular masses) with sodium montmorillonite (Na + -Mt) was studied using powder X-ray diffraction and infrared spectroscopy. The 001 reflection for GC/Na + -Mt intercalates varied with the amount COC added, and the measured d 001 value increased from 1.29 nm to as large as 2.22 nm at equal-mass coverage of the COC to Na + -Mt. In general, when intercalated, the cyclic carbonyl (C O) stretch and the fundamental hydroxyl (O–H) stretch bands of COC derivatives were red-shifted with respect to these bands for neat COC, indicating strong ion-dipole interaction of the carbonyl group with interlayer Na + , and H-bonding of the OH group with both interlayer water and Mt surfaces. A stable and highly ordered intercalate was produced at a 1:1 mass loading with Mt in which about 6 GC molecules per unit cell (~ 7 molecules per Na + ion) replaced most of the interlayer water.

Nanocomposites of sodium smectite with polyether- and polystyrene-containing pendant cyclic carbonates offer a novel approach to improving hydraulic barrier properties of Na-smectite liners to saline leachates. The cyclic carbonate polyethers were prepared by cationic ring opening polymerization of a cyclic carbonate-containing epoxide, whilst polystyrene polymers having pendant cyclic carbonate groups were obtained from radical photopolymerization of styrene. Na-smectite nanocomposites of these polymers were formed via clay in situ polymerization and solution intercalation methods. X-ray diffraction (XRD) and FT-IR analysis confirmed that the polyether can be intercalated within the layers of smectite via in situ as well as solution intercalation of the pre-formed polymer. The cyclic carbonate polyether nanocomposite was more resistant to leaching in 3M aqueous sodium chloride than its respective cyclic carbonate. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 2421–2429