The concentrated polyaluminum chloride with tailor-made distribution of Al species: synthesis, distribution and transformation of Al species, and coagulation performance.

Production of concentrated polyaluminum chloride (PACl) with the proper distribution of Al species (Ala, Alb, and Alc) is still a challenging issue on both industrial and laboratory scale. Hence, the effects of total aluminum concentration (AlT) at high levels, regular basicity values, and low base injection rates on the distribution of Al species in PACl solutions were investigated using quadratic models. The results confirmed the possibility to synthesize tailor-made PACl solutions with a specified value of either Ala, Alb, or Alc within the range of 22-51%, 4-51%, or 0.5-74%, respectively. For instance, in agreement with the predicted value, a PACl sample rich in both Alb (42,200 ppm) and AlT was produced by applying the basicity of 1.7, AlT of 9.07% as Al2O3, and basification rate of 0.48 ml/h. In addition, the maximum Alc could be acquired by exploiting the highest C, B, and Q values. This condition also minimized both Ala and Alb. The trends of Ala and Alc changes by the increment of basicity were concave and convex, respectively, while Alb showed either a decreasing trend or a concave pattern based on the values of injection rate and AlT. The Alb-rich PACl sample was effectively applied for turbidity removal from synthetic wastewater at various pHs and initial turbidities. At best, residual turbidity of about 1% was observed after the coagulation process. These findings can be constructive for the production and application of tailor-made PACl.

Binding parameters and molecular dynamics of ß-lactoglobulin-vanillic acid complexation as a function of pH - part B: Neutral pH.

Interactions between the dimeric form of ß-lactoglobulin and vanillic acid were investigated at pH 7.2, using a variety of spectroscopic techniques and molecular dynamics (MD) simulations. FTIR and CD studies showed alterations in the secondary structure of the protein upon its interaction with the ligand. Fluorescence measurements indicated that the dimeric complex with the phenolic acid produced a large dissociation constant (KD) compared to the monomeric counterpart at acidic pH (part A of this series). Stoichiometry of 1:1 was identified for the ß-lactoglobulin-vanillic acid complex by Job plot analysis at neutral pH suggesting two ligand molecules can participate in binding with the dimer. Molecular docking and MD simulations suggested that the top-ranked binding sites of the ligand were located at the entrance of each ß-barrel structure of the dimer. These simulations also allowed identification of the contribution of water molecules, in the form of protein-water-ligand bridging interactions, to the complexes.

Binding parameters and molecular dynamics of ß-lactoglobulin-vanillic acid complexation as a function of pH - Part A: Acidic pH.

Protein-phenolic compound interactions are commonly investigated with inappropriate linear equations for the analysis of binding strength and stoichiometry. This work utilises more appropriate protocols for the investigation of molecular interactions between vanillic acid and ß-lactoglobulin at pH 2.4, where the protein predominately exists as a monomer. Non-linear binding and Job plot analysis were conducted on fluorescence data to effectively determine the interaction's dissociation constant (KD, 2.93 × 10-5 M) and stoichiometry (1:1). Furthermore, spectroscopic techniques revealed statistically significant alterations to the conformational characteristics of ß-lactoglobulin upon complexation. Molecular dynamics (MD) simulations support a 1:1 interaction stoichiometry and reveal that the stabilisation of vanillic acid was dynamic in nature but mainly supported by four π-alkyl interactions and one hydrogen bond, located within the ß-barrel of the monomer. Water molecules, which are generally not accounted for in MD simulation analysis, were shown to be an important factor in the ligand stabilization via bridging interactions.

Fabrication of the robust and recyclable tyrosinase-harboring biocatalyst using ethylenediamine functionalized superparamagnetic nanoparticles: nanocarrier characterization and immobilized enzyme properties.

Immobilized tyrosinase onto the functionalized nanoparticles with the ability to be reused easily in different reaction cycles to degrade phenolic compounds is known as a substantial challenge, which can be overcome through surface modification of the particles via proper chemical groups. Herein, the synthesis and silica coating of superparamagnetic nanoparticles using a simple procedure as well as their potential for tyrosinase immobilization were demonstrated. Therefore, N-[3-(trimethoxysilyl)propyl]ethylenediamine was used to functionalize the silica-coated nanoparticles with amine groups. Then, the ethylenediamine functionalized magnetic nanoparticles (EMNPs) were suspended in a solution containing tetrahydrofuran and cyanuric chloride (as an activating agent) to modify nanocarriers. To immobilize enzyme, a mixture of tyrosinase and cyanuric chloride functionalized magnetic nanoparticle (Cyc/EMNPs) was shaken at room temperature. The particles were characterized by EDX, TGA, SEM, FTIR, and TEM. As a result, the successful functionalization of the magnetic nanoparticles and covalent attachment of tyrosinase onto the Cyc/EMNPs were confirmed. The fabricated nano-biocatalyst particles were semi-spherical in shape. The immobilized tyrosinase (Ty-Cyc/EMNPs) exhibited remarkable reusability of six consecutive reaction cycles while no considerable loss of activity was observed for the first three cycles. Moreover, the excellent stability of the biocatalyst at different temperatures and pHs was proved. The Ty-Cyc/EMNPs with interesting features are promising for practical applications in biosensor development and wastewater treatment.

Biotransformation of phenol in synthetic wastewater using the functionalized magnetic nano-biocatalyst particles carrying tyrosinase.

Low conversion efficiency and long-processing time are some of the major problems associated with the use of biocatalysts in industrial processes. In this study, modified magnetic iron oxide nanoparticles bearing tyrosinase (tyrosinase-MNPs) were employed as a magnetic nano-biocatalyst to treat phenol-containing wastewater. Different factors affecting the phenol removal efficiency of the fabricated nano-biocatalyst such as catalyst dosage, pH, temperature, initial phenol concentration, and reusability were investigated. The results proved that the precise dosage of nano-biocatalyst was able to degrade phenol at the wide range of pHs and temperatures. The immobilized tyrosinase showed proper phenol degradation more than 70%, where the substrate with a high concentration of 2500 mg/L was subjected to phenol removal. The nano-biocatalyst was highly efficient and reusable, since it displayed phenol degradation yields of 100% after the third reuse cycle and about 58% after the seventh cycle. Moreover, the immobilized tyrosinase was able to degrade phenol dissolved in real water samples up to 78% after incubation for 60 min. It was also reusable at least seven cycles in the real water sample. The results proved the effectiveness and applicability of the fabricated nano-biocatalyst to treat phenol-containing wastewaters in a shorter time and higher efficiency even at high phenol concentration. The developed nano-biocatalyst can be promising for the micropollutants removal and an alternative for the catalysts used in traditional treatment processes.

Covalent immobilization of tyrosinase onto cyanuric chloride crosslinked amine-functionalized superparamagnetic nanoparticles: Synthesis and characterization of the recyclable nanobiocatalyst.

Magnetic nanoparticles (MNPs) were synthesized using the chemical co-precipitation method. Then the nanoparticles were coated with silica via hydrolysis of tetraethyl orthosilicate using the sol-gel process. The silica coated magnetic nanoparticles were amine-functionalized with 3-aminopropyltriethoxysilane/ethanol solution. Subsequently, the nanoparticles were added to a solution of cyanuric chloride in tetrahydrofuran to synthesize cyanuric chloride-functionalized magnetic nanoparticles (Cy-MNPs). For covalent immobilization of tyrosinase, Cy-MNPs were added to a freshly prepared tyrosinase solution and the mixture was shaken. The FTIR spectra, as well as EDX, analysis proved the covalent immobilization of tyrosinase on the nanoparticles. The magnetic properties of tyrosinase-immobilized magnetic nanoparticles (tyrosinase-MNPs) were specified by VSM analysis. TEM images indicated that the most of the tyrosinase-MNPs had a semi-spherical shape with an average size of 17nm. The synthesized nanoparticles had a high loading capacity of 194mg tyrosinase/g nanoparticles with an immobilization yield of 69%. The optimum condition for both free and immobilized tyrosinase was found at pH 7.0 and 35°C. The immobilized enzyme was active after treatment of the particles at various pHs and temperatures for 100min. In addition, reusability of the immobilized enzyme was investigated and it was proved its suitability to be used for more than 7 cycles. Also, tyrosinase-MNPs remained about 70% of its initial activity after storing at 4°C for 40days. This nanobiocatalyst with interesting properties is promising for practical application in wastewater treatment and biosensor development.

Data in support of covalent attachment of tyrosinase onto cyanuric chloride crosslinked magnetic nanoparticles.

Preparation and characterization of cross linked amine-functionalized magnetic nanoparticles as an appropriate support for covalent immobilization on tyrosinase was presented in the study "Covalent immobilization of tyrosinase onto cyanuric chloride crosslinked amine-functionalized superparamagnetic nanoparticles: synthesis and characterization of the recyclable nanobiocatalyst" (Abdollahi et al., 2016 ) [1]. Herein, complementary data regarding X-ray powder diffraction (XRD) to characterize the synthesized magnetic nanoparticles, and transmission electron microscopy (TEM) to determine the size and morphology of tyrosinase immobilized magnetic nanoparticles (tyrosinase-MNPs) were reported. The purification results of the extracted tyrosinase from mushroom Agaricus bisporus were provided in a purification table. The covalent immobilization of tyrosinase onto cyanuric chloride functionalized magnetic nanoparticles was proved by performing thermo-gravimetric and energy-dispersive X-ray spectroscopy analyses. The operational stability of immobilized tyrosinase was investigated by incubating tyrosinase-MNPs at different pH and temperatures.

Serum Copper and Zinc Levels Among Iranian Colorectal Cancer Patients.

Alterations of trace element concentrations adversely affect biological processes and could promote carcinogenesis. Only a few studies have investigated the degree of changes in copper and zinc levels in colorectal cancer (CRC). The aim of the present study was to compare the serum copper (Cu) and zinc (Zn) concentrations in patients with CRC from Iran with those of healthy subjects. Cu and Zn concentrations in the serum of 119 cancer patients and 128 healthy individuals were measured by atomic absorption spectrometry. We found a significant decrease in the total mean serum Cu and Zn concentrations in CRC patients as compared with the control group (137.5 ± 122.38 vs. 160.68 ± 45.12 µg/dl and 81.04 ± 52.05 vs. 141.64 ± 51.75, respectively). However, the serum Cu/Zn ratio in the patient group was significantly higher than that measured in the control group (p = 0.00). There was no significant difference in the mean values of serum Cu and Zn concentrations between young (<60 years) and elderly (≥60 years) patients. However, the Cu/Zn ratio in <60-year cases was significantly higher than that in ≥60-year age group (p < 0.05). In addition, mean serum Cu level in normal weight patients was significantly higher than that in overweight/obese cases (132.31 ± 87.43 vs. 103.81 ± 53.72 µg/dl, respectively) (p < 0.05). There was no difference in mean serum Cu and Zn concentrations in patients stratified by the site, stage, or differentiation grade of tumors. Our findings suggest that imbalance in Cu and Zn trace element level is associated with CRC and might play an important role in cancer development among Iranian patients.

MTHFR C677T and A1298C variant genotypes and the risk of microsatellite instability among Iranian colorectal cancer patients.

Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme in the folate metabolic pathway. We aimed to test the hypothesis that C677T and A1298C variants of MTHFR predispose to microsatellite instable (MSI) colorectal cancer. We determined MTHFR genotypes in 175 sporadic colorectal cancer patients and a total of 231 normal controls in Shiraz, Southern Iran. Among the genotypes found in our samples, MTHFR CT and CT+TT were associated with increased risk for CRC incidence [odds ratio (OR)=2.4, 95% confidence interval (95%CI)=1.8-4.4; OR=2.4, 95%CI=1.6-3.6, respectively]. Double heterozygotes 677CT/1298AC and double homozygote 677TT/1298AA and 677CC/1298CC genotypes also showed a significantly increased risk of developing CRC compared with the wild-type 677CC/1298AA genotypes of the controls. Among the 151 tumors tested, 36 (23.8%) were MSI+. MSI was more common in proximal tumors (OR=10.4; 95%CI=3.9-27.8) and in smokers (OR=2.9; 95%CI=1.3-6.7). In a case-control comparison, the MTHFR 677CT+TT genotype was strongly associated with MSI (OR=2.6; 95%CI=1.3-5.3). Hypermethylation of mismatch repair genes was positively related with MSI incidence in these tumor series (P=0.00). Our data suggest that the MTHFR 677CT+TT variant genotype may be a risk factor for MSI+ cancer.