Phytases are a group of digestive enzymes which are commonly used as feed enzymes. These enzymes are used exogenously in the feeds of monogastric animals thereby it improves the digestibility of phosphorous and thus reduces the negative impact of inorganic P excretion on the environment. Even though these enzymes are widely distributed in many life forms, microorganisms are the most preferred and potential source of phytase. Despite the extensive availability of the phytase-producing microbial consortia, only a few microorganisms have been known to be exploited at industrial level. The high costs of the enzyme along with the incapability to survive high temperatures followed by the poor storage stability are noted to be the bottleneck in the commercialization of enzymes. For this reason, besides the conventional fermentation approaches, the applicability of cloning, expression studies and genetic engineering has been implemented for the past few years to accomplish the abovesaid benefits. The site-directed mutagenesis as well as knocking out have also validated their prominent role in microbe-based phytase production with enhanced levels. The present review provides detailed information on recent insights on the modification of phytases through heterologous expression and protein engineering to make thermostable and protease-resistant phytases.

Absorption is an eminent technology for volatile organic compounds (VOCs) elimination with the merits of high efficiency and low cost. Absorbent plays a critical role in the absorption process, and the thermal stability, saturation capacity, and regeneration performance should be concerned. As a kind of green and eco-friendly solvent, ionic liquid (IL) is expected to be a substitute for the conventional VOCs absorbent. In this study, 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim][PF₆]) is employed to absorb the modeling VOCs (toluene and acetone). Moreover, the used [Bmim][PF₆] is recovered by thermal distillation and the reusability is then conducted by consecutive batch experiments. Based on that, the thermal stability of [Bmim][PF₆] is comprehensively examined, in which the kinetic and thermodynamic parameters are also calculated. Results reveal that [Bmim][PF₆] owned promising toluene absorption performance with inlet concentration of 3000 mg/m³ and flow rate of 300 mL/min at 20 °C, it possesses the saturated adsorption capacity of 5.16 mg/g. [Bmim][PF₆] also shows satisfying thermal stability up to 610 K. In addition, thermal distillation is proved to be a reliable regeneration route on account of the recovered [Bmim][PF₆] remained satisfying capacity even after five cycles.

Direct utilization of waste polyethylene terephthalate (PET) from the environment to form highly porous aerogel technology for oil absorption is an attractive approach from the view point of green chemistry. However, the oil absorption reaction is limited by low oil absorption capacity and less stability. For now, silica aerogel are used to solve these problem. Our goal is to substitute to these silica aerogel with PET aerogel technology. Herein, we have prepared an environmental waste PET based aerogel with 1.0:0.5 wt% PET, polyvinyl alcohol (PVA), and glutaraldehyde (GA) 0.2% v/v were dispersed in 10 mL DI water, followed by homogenization (30 min), sonication (10 min), and ageing (2 h) at 70 °C. To escape macroscopic cracking, cooling (8 h) at 4 °C was followed by freezing (6 h), freeze drying at −80 °C, and 5 mTorr for 18 h. The hybrid PET aerogel displays excellent performance towards oil absorption. Notably it showed high absorption capacity towards the different oils about 21–40 times its own weight, depending on the viscosity and density of the oil and solvents within 15–35 s, 25 °C, and 2 × 2 cm aerogel size. In addition, the aerogel shows there is no change in structure after several recycles due to high mechanical strength. Furthermore, because of the PET aerogel's high porosity (99.74%) and low density (0.0311 g/cm³), close bonding between PET-PVA occurs. Therefore, aerogel shows hydrophobic nature, good mechanical strength, high thermal stability, arrangement of the interconnected fibrillar pore network offers a high surface to volume ratio, low surface energy, high surface roughness, and more reusability. All these parameters are responsible for high oil absorption.

In this study, a sustainable NH₂-MIL-101(Al) is synthesized and subjected to characterization for cryogenic CO₂ adsorption, isotherms, and thermodynamic study. The morphology revealed a highly porous surface. The XRD showed that NH₂-MIL-101(Al) was crystalline. The NH₂-MIL-101(Al) decomposes at a temperature (>500 °C) indicating excellent thermal stability. The BET investigation revealed the specific surface area of 2530 m²/g and the pore volume of 1.32 cm³/g. The CO₂ adsorption capacity was found to be 9.55 wt% to 2.31 wt% within the investigated temperature range. The isotherms revealed the availability of adsorption sites with favorable adsorption at lower temperatures indicating the thermodynamically controlled process. The thermodynamics showed that the process is non-spontaneous, endothermic, with fewer disorders, chemisorption. Finally, the breakthrough time of NH₂-MIL-101(Al) is 31.25% more than spherical glass beads. The CO₂ captured by the particles was 2.29 kg m⁻³. The CO₂ capture using glass packing was 121% less than NH₂-MIL-101(Al) under similar conditions of temperature and pressure.

Human exposure to particulate matter (PM) originating from air pollution is inevitable since more and more population is present in large cities that are characterized by poor air quality. The impact on human health is evident and we need to intensify research regarding this problem to get molecular insight into versatile effects of chronic exposure to PM inducing organism responses and initiating the development of selected disorders. Herein, the impact of standard PM representing urban pollution on the structure and function of human serum albumin (HSA) was evaluated by the application of various analytical techniques. HSA was selected due to its high likeliness of being exposed to PM because of the abundance of this protein in blood. The studies were focused mainly on the inorganic residue of PM resulting from removing organic components by a low-temperature plasma. To mimic physiological conditions, dialysis technique was used to simulate the release of nanoparticles and ions from PM to aqueous environment under, which in turn may interact with biomolecules inside the living system. Capture of metals from the bulk suspension was found for many metals like Al, Fe, Zn and Pb in quantities of more than 1 mol of metal ions per mole of HSA. No significant structural changes of the protein upon dialysis with PM were observed, however, an increase in the thermal stabilization of the HSA structure was observed. Moreover, the interaction of HSA dialyzed in the presence of PM with selected drugs (warfarin, aspirin) was negatively affected, indicating a lower affinity of drugs towards the protein, even though only small conformational changes of the PM exposed protein were observed. Our findings point to a possible interference of air pollutants with the drugs taken by patients living in highly polluted areas.

A severe air quality degradation event occurred in the Santiago Metropolitan Area (SMA), Chile, in June 2014. Meteorological and air quality measurements from 11 stations in the area as well as numerical simulations using the Weather and Research Forecasting (WRF) model were used to explain the main reasons for the occurrence of elevated particulate matter (PM) concentrations. The conditions were characterized with formation of a coastal low in central Chile between the southeastern anticyclone and a high-pressure system over Argentina. At a local scale, these conditions generated a depression at the base of the inversion layer, an increase in the vertical thermal stability, lower humidity and low-wind conditions, which were conducive to a decrease in pollutant dispersion and insufficient ventilation of the polluted air. Measurements and simulations using the WRF model revealed a vertical structure of the boundary layer during these stagnant conditions and provided a basis for a trajectory analysis. The back-trajectory calculation showed that the transport of air parcels was contained in the valley during the highest concentrations. The analysis also enabled the definition of the threshold values of a simple indicator of air pollution (ventilation coefficient, VC), which confirmed the evolution of the episode and divided the observed daily concentrations into two groups, with one including values above the limits prescribed by the national air quality standards (NAQS) and the other including values below these limits. For the SMA, the daily PM concentrations above the NASQ limits were associated with an overall mean threshold value of VC below 500 m² s⁻¹ (for PM₂.₅) and 300 m² s⁻¹ (for PM₁₀). To apply the VC analysis to other pollutants and different geographic locations, different threshold values should be evaluated.

Biochar has recently been fascinating for research in many environment areas due to its potential applications. In this research, graphene, and nano zero-valent iron (nZVI) were integrated with biochar and used for copper immobilization in the soil. Initially, the biomass feedstock was pyrolyzed under N₂ atmosphere from 150 to 650 °C and immersed in an aqueous solution containing graphene, and then impregnated with nZVI. Laboratory characterization with different instruments (eg. SEM, TEM, XRD, UV–Vis, VSM, and XPS) showed that graphene sheets and reactive nZVI were loaded on the biochar surface during the development process. The 450 °C was considered as optimum pyrolysis temperature based on the effective surface properties of the obtain biochar material. Boehm titration and functional group analysis confirmed the presence of carboxylic groups, phenolic groups in the corn stack biochar supported graphene oxide/nZVI (CTBC-GO/nZVI). Thermogravimetric analysis showed that nZVI incorporation to biochar surface could improve thermal stability as compared to graphene oxide incorporated biochar and pristine biochar. The material was utilized for copper (Cu) immobilization in the soil and a comparative evaluation was established on the basis of efficiency. The soil experiment showed that the CTBC-GO/nZVI has a superior immobilization efficiency of copper than pristine biochar and GO@BC. The available Cu content decreased by > 65% in CTBC-GO/nZVI amended soil after 14 days. Sequential extraction procedure (SEP) results suggested that CTBC-GO/nZVI promoted the conversion of more accessible Cu into the less accessible and bioavailable forms to reduce the toxicity of Cu. Therefore, CTBC-GO/nZVI composite is a promising and effective amendment for immobilizing Cu in contaminated soils and improving soil properties.This work can put forward a strategy to develop magnetic biochar composites and an application towards toxic heavy metals immobilization in soil.

Microplastics (particle size <5 mm) are an emerging contaminant for aquatic environmental, which have attracted increasing attention in worldwide range. In this study, an improved fluorescent staining method for detection and quantification of microplastics was developed based on thermal expansion and contraction. This method is effective in detection of polyethylene, polystyrene, polyvinyl chloride and polyethylene terephthalate plastic particles. In order to avoid error statistics caused by pretreatment, various characterizations of microplastics were measured after heated, such as microstructure, compositions and thermostability. The results showed that there was no significant damage to microplastics even under heating condition at 75 °C for 30 min, and the stained microplastics had strong stability for up to two months. Moreover, this method has been successfully applied to the quantification of microplastics in biological samples and result showed there were about 54 particles g⁻¹ (dry weight) microplastics in the Sipunculus nudus. This new method provides a reliable method for quantitative analysis of microplastics in environment and biological tissue.

The silica-composited biochars (SBC) were synthesized by adding silica particulates into bamboo biomass during pyrolysis at 700 °C to examine the effect of silica addition on biochar stabilities and adsorption properties for tetracycline (TC). Silica addition increased the total pore volume and average pore diameter of biochar due to the abundant mesopores in SBC, but decreased specific surface area due to the blockage of biochar pore with silica particles. Biochar stability was obviously enhanced with silica addition due to the decreased atomic ratio of H/C and O/C, the reduced C loss amount after chemical oxidation treatment, and the increased thermal stability. The adsorption capacities of SBC for TC were greatly enhanced with silica addition and increased with the increasing silica addition amount, which can be attributed to the facilitating effect of π–π electron donor acceptor (EDA) interaction and pore-filling effect. In addition, silica addition can also effectively enhance the oxidation resistance of biochar for TC adsorption, since the decreased degree (δ) of TC adsorption amounts on the biochars after chemical oxidation decreased with the increasing silica addition level. The observed positive correlations between δ values and the corresponding C loss amount of biochars after chemical oxidation suggested that the high carbon stability was favorable for the maintenance of biochar adsorption capacity. These results can provide a new way to improve biochar stabilities, aging resistance, and adsorption properties for organic pollutants.

One possible way to reduce the environmental impacts of pesticides is by nanostructuring biocides in nanocarriers because this promotes high and localized biocidal activity and can avoid toxicity to non-target organisms. Neem oil (NO) is a natural pesticide with toxicity concerns to plants, fish, and other organisms. Thus, loading NO in a safe nanocarrier can contribute to minimizing its toxicity. For this study, we have characterized the integrity of a nanosilica-neem oil-based biocide delivery system (SiO₂NP#NO BDS) and evaluated its effectiveness in reducing NO toxicity by the Allium cepa test. NO, mainly consisted of unsaturated fatty acids, was well binded to the SiO₂NP with BTCA crosslinker. Overall, this material presented all of its pores filled with the NO with fatty acid groups at both the surface and bulk level of the nanoparticle. The thermal stability of NO was enhanced after synthesis, and the NO was released as zero-order model with a total of 20 days without burst release. The SiO₂NP#NO BDS was effective in reducing the individual toxicity of NO to the plant system. NO in single form inhibited the seed germination of A. cepa (EC₅₀ of 0.38 g L⁻¹), and the effect was no longer observed at the BDS condition. Contrarily to the literature, the tested NO did not present cyto- and geno-toxic effects in A. cepa, which may relate to the concentration level and composition.