Mineralization of palm oil mill effluent by advanced oxidation processes: A review on current trends and the way forward.

Palm oil mill effluent (POME) is regarded as deleterious to the environment, primarily owing to the substantial volume of waste it produces during palm oil extraction. In terms of contaminant composition, POME surpasses the pollutant content typically found in standard municipal sewage, therefore releasing it without treatment into water bodies would do irreparable damage to the environment. Main palm oil mills are normally located in the proximity of natural rivers in order to take advantage of the cheap and abundant water source. The same rivers are also used as a water source for many villages situated along the river banks. As such, it is imperative to degrade POME before its disposal into the water bodies for obvious reasons. The treatment methods used so far include the biological processes such as open ponding/land application, which consist of aerobic as well as anaerobic ponds, physicochemical treatment including membrane technology, adsorption and coagulation are successful for the mitigation of contaminants. As the above methods require large working area and it takes more time for contaminant degradation, and in consideration of the strict environmental policies as well as palm oil being the most sort of vegetable oil in several countries, numerous researchers have concentrated on the emerging technologies such as advanced oxidation processes (AOPs) to remediate POME. Methods such as the photocatalysis, Fenton process, sonocatalysis, sonophotocatalysis, ozonation have attained special importance for the degradation of POME because of their efficiency in complete mineralization of organic pollutants in situ. This review outlines the AOP technologies currently available for the mineralization of POME with importance given to sonophotocatalysis and ozonation as these treatment process removes the need to transfer the pollutant while possibly degrading the organic matter sufficiently to be used in other industry like fertilizer manufacturing.

Conjunctival epithelial cells resist productive SARS-CoV-2 infection

Although tropism of SARS-CoV-2 for respiratory tract epithelial cells is well established, an open question is whether the conjunctival epithelium is also a target for SARS-CoV-2. Conjunctival epithelial cells, which express viral entry receptors ACE2 and TMPRSS2, constitute the largest exposed epithelium of the ocular surface tissue, and may represent a relevant viral entry route. To address this question, we generated an organotypic air-liquid-interface model of conjunctival epithelium, composed of progenitor, basal and superficial epithelial cells and fibroblasts, which could be maintained successfully up to day 75 of differentiation. Using single-cell RNA Seq, with complementary imaging and virological assays, we observed that while all conjunctival cell types were permissive to SARS-CoV-2 genome expression, a productive infection did not ensue. The early innate immune response to SARS-CoV-2 infection in conjunctival cells was characterised by a robust autocrine and paracrine NF-K{beta} activity, without activation of antiviral interferon signalling. Collectively, these data enrich our understanding of SARS-CoV-2 infection at the human ocular surface, with potential implications for the design of preventive strategies and conjunctival transplants.

Waste Fiber-Based Poly(hydroxamic acid) Ligand for Toxic Metals Removal from Industrial Wastewater.

Toxic metals in the industrial wastewaters have been liable for drastic pollution hence a powerful and economical treatment technology is needed for water purification. For this reason, some pure cellulosic materials were derived from waste fiber to obtain an economical adsorbent for wastewater treatment. Conversion of cellulose into grafting materials such as poly(methyl acrylate)-grafted cellulose was performed by free radical grafting process. Consequently, poly(hydroxamic acid) ligand was produced from the grafted cellulose. The intermediate products and poly(hydroxamic acid) ligand were analyzed by FT-IR, FE-SEM, TEM, EDX, and XPS spectroscopy. The adsorption capacity (qe) of some toxic metals ions by the polymer ligand was found to be excellent, e.g., copper capacity (qe) was 346.7 mg·g-1 at pH 6. On the other hand, several metal ions such as cobalt chromium and nickel also demonstrated noteworthy sorption capacity at pH 6. The adsorption mechanism obeyed the pseudo second-order rate kinetic model due to the satisfactory correlated experimental sorption values (qe). Langmuir model isotherm study showed the significant correlation coefficient with all metal ions (R2 > 0.99), indicating that the single or monolayer adsorption was the dominant mode on the surface of the adsorbent. This polymer ligand showed good properties on reusability. The result shows that the adsorbent may be recycled for 6 cycles without any dropping of starting sorption capabilities. This polymeric ligand showed outstanding toxic metals removal magnitude, up to 90-99% of toxic metal ions can be removed from industrial wastewater.

Genomic data of two Bacillus and two Pseudomonas strains isolated from the acid mine drainage site at Mamut Copper Mine, Ranau, Malaysia.

The genomic data of four bacteria strains isolated from the abandoned Mamut Copper Mine, an Acid Mine Drainage (AMD) site is presented in this report. Two of these strains belong to the genus Bacillus, while the other two belong to the genus Pseudomonas. The draft genome size of Pseudomonas sp. strain MCMY3 was 6,396,595 bp (GC: 63.3%), Bacillus sp. strain MCMY6 was 6,815,573 bp (GC: 35.2%), Bacillus sp. strain MCMY13 was 5,559,059 bp (GC: 35.5%) and Pseudomonas sp. strain MCMY15 was 7,381,777 bp (GC: 64.8%). These four genomes contained 493, 495, 495 and 579 annotated subsystems, respectively. The sequence data are available at GenBank sequence read archive with accessions numbers SRX7859406, SRX7859404, SRX7859405 and SRX7293032 for strains MCMY3, MCMY6, MCMY13 and MCMY15, respectively.

Application of Plasmonic Metal Nanoparticles in TiO2-SiO2 Composite as an Efficient Solar-Activated Photocatalyst: A Review Paper.

Over the last decade, interest in the utilization of solar energy for photocatalysis treatment processes has taken centre-stage. Researchers had focused on doping TiO2 with SiO2 to obtain an efficient degradation rate of various types of target pollutants both under UV and visible-light irradiation. In order to further improve this degradation effect, some researchers resorted to incorporate plasmonic metal nanoparticles such as silver and gold into the combined TiO2-SiO2 to fully optimize the TiO2-SiO2's potential in the visible-light region. This article focuses on the challenges in utilizing TiO2 in the visible-light region, the contribution of SiO2 in enhancing photocatalytic activities of the TiO2-SiO2 photocatalyst, and the ability of plasmonic metal nanoparticles (Ag and Au) to edge the TiO2-SiO2 photocatalyst toward an efficient solar photocatalyst.

Adaptive Strategies of Bacillus thuringiensis Isolated from Acid Mine Drainage Site in Sabah, Malaysia.

The adaptive process in bacteria is driven by specific genetic elements which regulate phenotypic characteristics such as tolerance to high metal ion concentrations and the secretion of protective biofilms. Extreme environments such as those associated with heavy metal pollution and extremes of acidity offer opportunities to study the adaptive mechanisms of microorganisms. This study focused on the genome analysis of Bacillus thuringiensis (Bt MCMY1), a gram positive rod shaped bacterium isolated from an acid mine drainage site in Sabah, Malaysia by using a combination of Single Molecule Real Time DNA Sequencing, Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). The genome size of Bt MCMY1 was determined to be 5,458,152 bases which was encoded on a single chromosome. Analysis of the genome revealed genes associated with resistance to Copper, Mercury, Arsenic, Cobalt, Zinc, Cadmium and Aluminum. Evidence from SEM and FTIR indicated that the bacterial colonies form distinct films which bear the signature of polyhydroxyalkanoates (PHA) and this finding was supported by the genome data indicating the presence of a genetic pathway associated with the biosynthesis of PHAs. This is the first report of a Bacillus sp. isolated from an acid mine drainage site in Sabah, Malaysia and the genome sequence will provide insights into the manner in which B. thuringiensis adapts to acid mine drainage.

Parametric and adsorption kinetic studies of methylene blue removal from simulated textile water using durian (Durio zibethinus murray) skin.

In this study, durian (Durio zibethinus Murray) skin was examined for its ability to remove methylene blue (MB) dye from simulated textile wastewater. Adsorption equilibrium and kinetics of MB removal from aqueous solutions at different parametric conditions such as different initial concentrations (2-10 mg/L), biosorbent dosages (0.3-0.7 g) and pH solution (4-9) onto durian skin were studied using batch adsorption. The amount of MB adsorbed increased from 3.45 to 17.31 mg/g with the increase in initial concentration of MB dye; whereas biosorbent dosage increased from 1.08 to 2.47 mg/g. Maximum dye adsorption capacity of the durian skin was found to increase from 3.78 to 6.40 mg/g, with increasing solution pH. Equilibrium isotherm data were analyzed according to Langmuir and Freundlich isotherm models. The sorption equilibrium was best described by the Freundlich isotherm model with maximum adsorption capacity of 7.23 mg/g and this was due to the heterogeneous nature of the durian skin surface. Kinetic studies indicated that the sorption of MB dye tended to follow the pseudo second-order kinetic model with promising correlation of 0.9836 < R(2) < 0.9918.

Asymmetric effect of mechanical stress on the forward and reverse reaction catalyzed by an enzyme.

The concept of modulating enzymatic activity by exerting a mechanical stress on the enzyme has been established in previous work. Mechanical perturbation is also a tool for probing conformational motion accompanying the enzymatic cycle. Here we report measurements of the forward and reverse kinetics of the enzyme Guanylate Kinase from yeast (Saccharomyces cerevisiae). The enzyme is held in a state of stress using the DNA spring method. The observation that mechanical stress has different effects on the forward and reverse reaction kinetics suggests that forward and reverse reactions follow different paths, on average, in the enzyme's conformational space. Comparing the kinetics of the stressed and unstressed enzyme we also show that the maximum speed of the enzyme is comparable to the predictions of the relaxation model of enzyme action, where we use the independently determined dissipation coefficient [Formula: see text] for the enzyme's conformational motion. The present experiments provide a mean to explore enzyme kinetics beyond the static energy landscape picture of transition state theory.

Quantitative imaging of selenoprotein with multi-isotope imaging mass spectrometry (MIMS).

Multi-isotope imaging mass spectrometry (MIMS) allows high resolution quantitative imaging of protein and nucleic acid synthesis at the level of a single cell using stable isotope labels. We employed MIMS to determine the compartmental localization of selenoproteins tagged with stable isotope selenium compounds in human aortic endothelial cells (HAEC), and to compare the efficiency of labeling (to determine the ideal selenium source) from these compounds: [82Se]-selenite, [77Se]-seleno-methionine, and [76Se]-methyl-selenocysteine. We found that all three selenium sources appear to be localized in the nucleus as well as in the cytoplasm in HAEC. Seleno-methionine appears to be a better source for (seleno)protein synthesis. For MIMS detection, we compared freeze-drying to thin layer vs. thin sectioning for sample preparation. MIMS provides a unique and novel way to dissect selenoprotein synthesis in cells.

Sonophotocatalysis in advanced oxidation process: a short review.

Sonophotocatalysis involves the use of a combination of ultrasonic sound waves, ultraviolet radiation and a semiconductor photocatalyst to enhance a chemical reaction by the formation of free radicals in aqueous systems. Researchers have used sonophotocatalysis in a variety of investigations i.e. from water decontamination to direct pollutant degradation. This degradation process provides an excellent opportunity to reduce reaction time and the amount of reagents used without the need for extreme physical conditions. Given its advantages, the sonophotocatalysis process has a futuristic application from an engineering and fundamental aspect in commercial applications. A detailed search of published reports was done and analyzed in this paper with respect to sonication, photocatalysis and advanced oxidation processes.