Central Composite Rotatable Design Research Articles

Parboiling process improves phytochemical, chemical, and technological properties of wild rice (Zizania sp.)

Wild rice (Zizania sp.) shows high protein, mineral, fiber, and low lipid contents, which makes this grain a good option for consumption as cooked rice or as an ingredient in food products. However, technological processing can affect the properties of wild rice. The parboiling process can be an alternative to improve the quality of wild rice grains, avoiding the decomposition of the endosperm and reducing nutrient loss during cooking. This study aimed to optimize the parboiling conditions and evaluate the effects on technological, chemical, and phytochemical characteristics. The grains were gelatinized in an autoclave under pressure and time defined by the central composite rotatable design methodology. Ash and lipids levels increased under high pressure and time, while starch digestibility decreased. The parboiling process pressure was the variable that most affected the accumulation of phytochemicals. The highest levels of bioactive compounds were obtained at intermediate pressures (73.54 kPa), while time did not effectively affect the phytochemical profile.

The combined effect of supercritical carbon dioxide and mild temperatures on pectin methylesterase inactivation in orange juice.

Pectin methylesterase (PME) is the target-enzyme in orange juice processing, and its inactivation preserves the original juice's cloud, a valuable quality attribute for consumers. This study was primarily undertaken to evaluate the combination of supercritical carbon dioxide (SC-CO2) and mild temperatures on PME inactivation in the juice. Physicochemical and color parameters were also evaluated. Pressures (P) in the range of 74 to 351 bar, temperatures (T) between 33°C and 67°C, and holding times (t) varying from 20 to 70 min were tested using a central composite rotational design. Determination of PME activity, pH, titratable acidity, soluble solids, ratio, lightness, °hue and chroma in freshly extracted/raw and treated juice samples, and total color difference (TCD) between raw and treated juice were carried out. The percentage of PME reduction widely ranged from 13.7% to 91.8%. The variable P had a significant effect (p ≤ 0.05) on TCD and acidity variation. T exhibited a significant effect on the PME reduction, TCD, and soluble solids variation; however, t impacted on the soluble solids variation only. The interaction between P and t (P.t) affected the soluble solids and acidity variation, and T.t affected TCD. The combination of SC-CO2 and mild temperatures is potentially capable of inactivating PME in orange juice.

Production of Human Milk Fat Substitutes by Lipase-Catalyzed Acidolysis: Immobilization, Synthesis, Molecular Docking and Optimization Studies

Human milk fat (HMF) triacylglycerols (TAGs) mainly contain palmitic acid esterified at the sn-2 position while oleic and other unsaturated fatty acids are located at positions sn-1,3. This study aimed at the production of HMF substitutes (HMFS) by lipase-catalyzed acidolysis of tripalmitin with oleic acid, in a solvent-free medium. Burkholderia cepacia lipase (BCL) was immobilized in silica (prepared with protic or aprotic ionic liquids) by covalent binding or encapsulation and used as biocatalyst. The supports and immobilized biocatalysts were characterized by FTIR, TGA, and SEM. Molecular docking analysis showed that BCL preferentially attacks oleic acid rather than tripalmitin, due to the lower free energy of hydrophobic binding with this acid (−6.5 kcal·mol−1) than with tripalmitin (5.4 kcal·mol−1). Therefore, the tripalmitin attack by BCL and subsequent HMFS production only occurs after the binding to most of the oleic acid molecules. The highest acidolysis activity was obtained with BCL immobilized by covalent binding in prepared silica with aprotic ionic liquid. A central composite rotatable design, as a function of temperature (58–72 °C) and oleic acid/tripalmitin molar ratio (MR = 2:1–6.8:1), was performed for acidolysis optimization. Under optimized conditions (58 °C and MR = 4:1 or 60 °C and MR = 2:1), the oleic acid incorporation of 28 mol.% was achieved after 48 h.

Empirical Modeling by Active Central Composite Rotatable Design: Orange 16 Dye Biosorption onto Biosorbents Based on Residual Bacterial Lactobacillus sp. Biomass

(1) Background: This research work proposes the ‘passive’ biosorption study of Orange 16 dye onto residual Lactobacillus sp. biomass immobilized in sodium alginate using an experimental modeling design. (2) Methods: It was applied the batch biosorption methodology was applied with a real-time determination of residual dye content and biosorption efficiency (Y, %). Empirical planning was used based on an active central composite rotatable design of 23 order in which three independent variables were considered, including residual biomass concentration (2.92–13.00 g/L, mean granule size of 0.7–1.0 mm) (X1), temperature (8–42 °C) (X2) and biosorption time (4–24 h) (X3), in association with the considered dependent variable (Y). The proposed mathematical model was validated using a few statistical tools. (3) Results: The batch biosorption experiments were permitted to propose a mathematical model considering a basic value and variation step for each selected independent variable and then to validate it. The maximum experimental dye removal was 79.98% when 11 g/L immobilized biosorbent was applied in an 89.76 mg/L dye-containing solution at 15 °C and 20 h. The significance of each independent variable on dye removal was investigated and, most importantly, explained. (4) Conclusions: The residual Lactobacillus sp. biomass can be applied as an alternative biosorbent for anionic dye removal from an aqueous solution.

A facile and eco-friendly hydrothermal synthesis of magnetic graphite nanocomposite and its application in water purification

In this research, a magnetic graphite nanocomposite (MGN) was synthesized by an easy and efficient hydrothermal process from magnetite nanoparticles (NP-SYN) and graphite nanoplatelets (GR). MGN was characterized by X-ray diffraction (XRD), Raman spectroscopy, energy-dispersive X-ray spectroscopy (EDS), field emission scanning electron microscopy (FESEM), N2 adsorption and desorption analysis, X-ray photoelectron spectroscopy (XPS), and point of zero charge (pHpzc) analysis. The thickness for GR was found to be 34 nm, and crystallite sizes for NP-SYN and MGN were around 37 and 48 nm, respectively. MGN shows the presence of GR and iron oxides from the NP-SYN. The surface areas for GR, NP-SYN, and MGN were around 191, 18, and 121 m2 g−1, respectively. The pHpzc results for GR, NP-SYN, and MGN ranged from 6 to 7. The NP-SYN, GR, and MGN were used as adsorbents to remove reactive black 5 (RB5) dye from aqueous solution. This method’s batch removal process was designed based on a central composite rotational design (CCRD). The efficiency of RB5 uptake for all adsorbents was obtained from the quadratic model under optimum conditions of prominent parameters by desirability function (mass of adsorbent 6.6 mg, dye concentration 85.1 mg L−1, and agitation speed 902.7 rpm). Under these conditions, the adsorption capacity values were 10.16, 92.08, and 28.83 mg g−1 for NP-SYN, GR, and MGN, respectively, indicating that the adsorption power of the nanoparticle increased after incorporating GR, maintaining its magnetic properties. Therefore, the proposed adsorbents in this work have potential for removing RB5 dye from water solutions.

Optimization of CMT Characteristic Parameters for Swing Arc Additive Manufacturing of AZ91 Magnesium Alloy Based on Process Stability Analysis.

The droplet transfer behavior and stability of the swing arc additive manufacturing process of AZ91 magnesium alloy based on the cold metal transfer (CMT) technique were studied by analyzing the electrical waveforms and high-speed droplet images as well as the forces on the droplet, and the Vilarinho regularity index for short-circuit transfer (IVSC) based on variation coefficients was used to characterize the stability of the swing arc deposition process. The effect of the CMT characteristic parameters on the process stability was investigated; then, the optimization of the CMT characteristic parameters was realized based on the process stability analysis. The results show that the arc shape changed during the swing arc deposition process; thus, a horizontal component of the arc force was generated, which significantly affected the stability of the droplet transition. The burn phase current I_sc_wait presented a linear function relation with IVSC, while the other three characteristic parameters, i.e., boost phase current I_boost, boost phase duration t_I_boost and short-circuiting current I_sc2, all had a quadratic correlation with IVSC. A relation model of the CMT characteristic parameters and IVSC was established based on the rotatable 3D central composite design; then, the optimization of the CMT characteristic parameters was realized using a multiple-response desirability function approach.

Cerium oxide nanoparticles: Biosynthesis, characterization, antimicrobial, ecotoxicity and photocatalytic activity

The present work aims to synthesize and characterize cerium oxide nanoparticles (CeO2-NPs) for application in the photodegradation of methylene blue – MB and methyl orange -MO. CeO2-NPs were prepared by biosynthesis method using Matricaria recutita extract. Minimal inhibitory concentration (MIC) was used to evaluate the antimicrobial activity against E. coli, S. aureus and K. pneumoniae. Microcrustacean Artemia salina was used for the ecotoxicity test. Central Composite Rotational Design (CCRD 22 and 23) was used to determine the ideal condition for the biosynthesis process and photocatalytic tests, respectively. CCRD 22 indicated the variables of extract concentration and time were significant 6 mg L−1 and 120 min, respectively with the higher yield of nanoparticles (15.71%), and CeO2-NPs crystallite diameter of 16.36 nm. CCRD 23 determined the ideal condition to [MB.MO] = 60 mg L−1, [CeO2-NPs] = 1 g L−1 and pH = 4, with 93% for the dyes photodegradation, indicating a pseudo-first order model (k = 0.0139 min−1). CeO2-NPs showed photocatalytic stability after 6 cycles. Ecotoxicity of CeO2-NPs did not show mortality for A. salina in the 10–2.5 mg mL−1. Therefore, it was possible to synthesize metallic nanoparticles of cerium oxide, with great potential for application as a nanophotocatalyst.

Standardization of process for development of instant chickpea using Desi and Kabuli variety

Chickpea is considered among the most important leguminous crops in the world but is not a regular meal pulse due to their long cooking time and lengthy preparatory procedure. This gives rise to the need of converting raw chickpea into convenient food. For the preparation of instant chickpea from Desi and Kabuli variety, Central Composite Rotatable Design (CCRD) under Response Surface Methodology (RSM) was employed which consisted of four variables i.e. sodium chloride (NaCl), sodium bicarbonate (NaHCO3), ammonium carbonate (NH4)2CO3 and temperature for soaking treatments. This design was used to develop models for the soaking time, change in colour, split %, alkalinity and cooking time for prepared instant chickpea samples. High-temperature hydration (60 °C) required lesser time to achieve the maximum hydration, whereas low-temperature hydration (30 °C) enhanced the hydration time and reduced the cooking time of instant chickpea significantly (P≤ 0.01) but this condition was inverse for the splitting/butterfly defects. Increasing the concentration of sodium bicarbonate and ammonium bicarbonate from 0.5 to 1.5 % during soaking treatments increased the splitting and alkalinity and produced undesirable colours in treated samples of chickpea. RSM optimized values concerning concentrations of different salts i.e. NaCl, NaHCO3, and (NH4)2CO3 in soaking solution were 0.59, 0.85 % and 0.82 %, respectively at 49.81 °C temperature for Desi instant chickpea having 11 minutes of cooking time whereas corresponding values for Kabuli chickpea were 1.07 % NaCl, 0.79 % NaHCO3, and 0.70 % (NH4)2CO3 at 46.53 °C temperature with 13 min cooking time.
 Keywords: Central Composite Rotatable Design, Chickpea, Soaking, Cooking time, Instant

A study on physic-chemical properties of goat milk yoghurt incorporated with kiwi fruit () pulp

The major objective of this research was to study the effect of different levels of kiwi () fruit pulp on physio-chemical properties of yogurt. During the study goat (capra hircus) milk yogurt incorporated with kiwi fruit pulp was analyzed for physico- chemical properties like fat, protein, moisture, total solids, ash, pH, synersis, acidity and colour properties etc. Yogurt was prepared by using different levels of kiwi fruit pulp. The data were statistically analysed by using Central composite rotatable design. The yogurt incorporated by kiwi fruit pulp different levels (0.20 to 2.50) showed overall acceptability sensory score. The chemical composition of yogurt prepared by addition of (0.20 to 2.50) kiwi fruit pulp having fat 0.20%, protein 0.17%, moisture 83.07%, total solids 16.70%, ash 0.15%, pH 3.26, Titrable acidity 1.43% and carbohydrate 14.67 percent.

Statistical Medium Optimization for the Production of Anti-Methicillin-Resistant Staphylococcus aureus Metabolites from a Coal-Mining-Soil-Derived Streptomyces rochei CMB47

The development of novel antibacterial drugs needs urgent action due to the global emergence of antibiotic resistance. In this challenge, actinobacterial strains from arid ecosystems are proving to be promising sources of new bioactive metabolites. The identified Streptomyces rochei strain CMB47, isolated from coal mine Saharan soil, provided an ethyl acetate extract which tested against a series of pathogens. It displayed a minimum inhibitory concentration of <0.439 µg/mL against MRSA. A statistical experimental design using a response surface methodology (RSM) based on the second-order rotatable central composite design (RCCD) was planned to develop an efficient fermentation process able to improve the bioactive metabolite production. The optimal conditions were determined for starch and NaNO3 concentrations, incubation time and the initial pH value, reaching the inhibition zone diameter of 20 mm, close to the experimental value, after validation of the model. A bioassay-guided fractionation of the crude extract provided the most active fractions, which were analyzed by HPLC equipped with a photodiode array detector and coupled online with an electrospray mass spectrometer (HPLC-DAD/ESI-MS), obtaining preliminary indications on the molecular structures of the metabolites. These results support the potential interest in further investigations into the purification and full characterization of the metabolites responsible for the biological activity observed so far.

Effect of soaking conditions on gamma-aminobutyric acid (GABA) and amino acids content in mung bean

Gamma-aminobutyric acid (GABA) offers numerous beneficial effects on human health, especially as blood pressure regulator and stress control. This functional compound is usually found in grains including mung bean. Mung bean (Vigna radiate) is one of the famous grains in Southeast Asia and is usually used in cooking as porridge or dessert by local people. It is highly nutritious with protein and antioxidants. In this study, the optimum soaking conditions were determined to enhance GABA content in mung beans. An RSM with a five-level, three-factorial, Central composite Rotatable Design (CCRD) was used to determine the soaking parameters to obtain maximum GABA content, essential amino acid (EAA) and total amino acids (TAA) in mung bean. The factors that were included in the RSM analysis were temperature, time and weight of beans to water ratio. GABA and amino acids were determined by using UPLC. The optimum condition for significant GABA production (p<0.05) was determined as 40°C, 4 hrs and 1:5 of temperature, time and soaking water level, respectively with the highest GABA content quantified as 130.12 mg/100 g dry weight (DW). Model optimization and validation were done according to the optimum conditions from the RSM analysis resulting in 124.17 mg/100 g DW of GABA, closer to the predicted value (130.07 mg/100 g DW). The optimum conditions determined by RSM could be beneficial to the industry, especially functional food production to cater for the demand for health-promoting products in the market.

Exogenous Auxin and Gibberellin on Fluoride Phytoremediation by Eichhornia crassipes.

High rates of fluorosis were reported worldwide as a result of human consumption of water with fluoride contents. Adjusting fluoride concentration in water as recommended by the World Health Organization (<1.5 mg L-1) is a concern and it needs to be conducted through inexpensive, but efficient techniques, such as phytoremediation. The application of phytohormones was investigated as a strategy to improve this process. Thus, the main goal of this research was to evaluate the effect of exogenous auxin and gibberellin on the tropical duckweed Eichhornia crassipes performance for fluoride phytoremediation. Definitive screening and central composite rotatable designs were used for experiments where fluoride concentration (5~15 mg L-1), phosphorus concentration (1~10 mg L-1), and pH (5~9) were assessed as well throughout 10 days. Fluoride contents were determined in solution and plant tissues by potentiometry. Higher concentrations of fluoride reflected on greater absorptions by plants, though in relative terms removal efficiencies were quite similar for all treatments (~60%). Auxin and acidic conditions favored fluoride removals per mass of plant. Fluoride accumulated mostly in leaves and auxin probably alleviated toxic effects on E. crassipes while gibberellin showed no effect. Therefore, E. crassipes could be employed as a fluoride accumulator plant for water treatment and exogenous auxin may be used to improve the process.

Optimization of fermentation medium components by response surface methodology (RSM) and artificial neural network hybrid with genetic algorithm (ANN-GA) for lipase production by Burkholderia cenocepacia ST8 using used automotive engine oil as substrate

Bioconversion of used automotive engine oil (UEO) into lipase was conducted via submerged fermentation by Burkholderia cenocepacia ST8, as a strategy for value-added product generation and waste management. Response surface methodology (RSM) and artificial neural network hybrid with genetic algorithm (ANN-GA) were employed to optimize the fermentation medium for enhancing extracellular lipase production by B. cenocepacia ST8. Employing a four-factor-five-level central composite rotatable experimental design (CCRD), a reduced quartic polynomial RSM model and ANN model (4-4-1) trained using Bayesian Regularization were developed to attain the optimized fermentation medium for maximum level of lipase production. The RSM model predicted the following as the optimum media constituents: 2.28% v/v of Tween 80, 2.26% v/v of UEO, 0.79% w/v of nutrient broth, and 1.33% w/v of gum arabic, with an actual lipase yield of 216 U/mL. While, ANN-GA predicted the optimum media constituents to be 3% v/v of Tween 80, 3% v/v of UEO, 0.72% w/v of nutrient broth, and 3.38% w/v of gum arabic, with actual lipase yield of 225 U/mL. In comparison to the unoptimized medium, optimized RSM and ANN-GA systems both demonstrated a 1.6-fold increment in lipase production. Tween 80 and nutrient broth concentrations were the most important variables influencing the lipase production. The findings of this study indicated that the ANN-GA and RSM could be useful for effective optimization of the fermentation medium for enzyme production.

DoE-enhanced development and validation of eco-friendly RP-HPLC method for analysis of safinamide and its precursor impurity: QbD approach

Design of Experiment (DoE) is an effective methodology for studying the relationship between variables and their dependent responses. In this study, DoE was employed for method development and optimization. A binary combination of safinamide mesylate (SAF) and its synthetic precursor p-hydroxybenzaldehyde (PHB) were analyzed by RP-HPLC. Method development focused on evaluating the effect of three independent factors; % EtOH, pH, and flow rate; on performance and efficiency of separation. A rotatable central composite design (CCD) was applied to determine crucial variables and optimize key performance parameters.Significant interest has been shown in green analytical chemistry as a means to reduce the use of hazardous organic solvents without degrading chromatographic performance. A green separation and quantification were performed using a Waters VDSpher PUR 100 C18-E column (5 µm, 250 × 4.6 mm) at a flow rate of 1 mL/min, utilizing abinary combination of mobile phase A: B (60:40, v/v). Phase A of the mobile phase consisted of 0.02 M ammonium formate and 0.02 M ammonium acetate, with the pH adjusted to 5.5 using formic acid. EtOH was utilized as mobile phase B, and 20 µL was employed as the injection volume. The technique was validated in accordance with ICH criteria. SAF had a linear range of 4–100 µg/mL, while PHB had a linear range of 0.2–10.0 µg/mL. Both analytes had R2 values of 0.9999, with detection limits of 0.95 and 0.06 µg/mL, respectively. The designed method could be applicable for regular QC analysis of SAF and its pharmaceutical product. GAPI and AGREE algorithms, which use 12 principles of green analytical chemistry, were used to evaluate the method greenness.

Optimization of Medium Constituents for the Production of Citric Acid from Waste Glycerol Using the Central Composite Rotatable Design of Experiments

Citric acid is currently produced by submerged fermentation of sucrose with the aid of Aspergillus niger mold. Its strains are characterized by a high yield of citric acid biosynthesis and no toxic by-products. Currently, new substrates are sought for production of citric acid by submerged fermentation. Waste materials such as glycerol or pomace could be used as carbon sources in the biosynthesis of citric acid. Due to the complexity of the metabolic state in fungus, there is an obvious need to optimize the important medium constituents to enhance the accumulation of desired product. Potential optimization approach is a statistical method, such as the central composite rotatable design (CCRD). The aim of this study was to increase the yield of citric acid biosynthesis by Aspergillus niger PD-66 in media with waste glycerol as the carbon source. A mathematical method was used to optimize the culture medium composition for the biosynthesis of citric acid. In order to maximize the efficiency of the biosynthesis of citric acid the central composite, rotatable design was used. Waste glycerol and ammonium nitrate were identified as significant variables which highly influenced the final concentration of citric acid (Y1), volumetric rate of citric acid biosynthesis (Y2), and yield of citric acid biosynthesis (Y3). These variables were subsequently optimized using a central composite rotatable design. Optimal values of input variables were determined using the method of the utility function. The highest utility value of 0.88 was obtained by the following optimal set of conditions: waste glycerol-114.14 g∙L-1and NH4NO3-2.85 g∙L-1.

Optimization of Making Edible Films based on Glycerol, Corn Oil and Whey Cheese using Rotatable Central Composite Design

Optimization of Making Edible Films based on Glycerol, Corn Oil and Whey Cheese using Rotatable Central Composite Design

Ozonation with Hydrogen Peroxide for Treating Wastewater from Industrial Potato Processing - a Preliminary Investigation

ABSTRACT Wastewater generated from agricultural activities and food production is a source of environmental pollution, and its treatment is a challenging technological issue. Ozone gas (O3), and the possibility of associating it with hydrogen peroxide (H2O2), has the potential to remove persistent organic compounds in effluents. In the present work, wastewater from industrial potato processing was characterized, and its treatment with ozone combined with hydrogen peroxide was assessed. The inlet ozone concentration and the flow rate were 84.5 mg L−1 and 62.5 mL min−1, respectively. The promising conditions of temperature, pH, and H2O2/O3 proportion were determined to reduce the chemical oxygen demand, turbidity, and color, according to a central composite rotatable design. The H2O2/O3 proportions were 0.1, 0.3, 0.5, and 0.6. Additionally, the response variables were evaluated as a function of the ozone and hydrogen peroxide treatment time for up to 24 h. The conditions obtained for treating wastewater from industrial potato processing were the following: temperature = 25°C; pH = 3.0, and H2O2/O3 proportion = 0.1. For the water quality parameters adopted, the combination of ozone and hydrogen peroxide was effective at removing color and turbidity. The chemical oxygen demand, color, and turbidity reduction stabilized after 1.16 h, with cumulative applied dosages of ozone and hydrogen peroxide equal to 380 mg L−1 and 35 mg L−1, respectively.

Studying the geobarier ability of furnace slag

Environmental pollution with mining waste containing dangerous metal cations necessitates the development of technologies for their disposal. This study proposes the use of blast furnace slag as a geobarrier for binding heavy metal cations. Such parameters as slag mass, temperature and time were used to determine the degree of binding of ferum and zinc cations when they are present together. A central rotatable composite experimental design was used to verify the results. According to the plan, the experiments were performed and the optimal conditions were determined with the help of statistical analysis. It was noted that a simultaneous increase in temperature and treatment time increases the degree of conversion for both ferric and zinc cations. An increase in the mass of slag leads to a decrease in the temperature and interaction time for ferum and zinc cations. However, for zinc cations, the maximum degree of conversion is 43.3% with their simultaneous presence. Experimental results showed that slag was more effective as a base for binding ferum and zinc cations with a conversion rate of 63.3% in concentrated solutions. The resulting regularities allow, by varying the process parameters, to bind metal cations in their joint presence.

Primary plant nutrients modulate the reactive oxygen species metabolism and mitigate the impact of cold stress in overseeded perennial ryegrass.

Overseeded perennial ryegrass (Lolium perenne L.) turf on dormant bermudagrass (Cynodon dactylon Pers. L) in transitional climatic zones (TCZ) experience a severe reduction in its growth due to cold stress. Primary plant nutrients play an important role in the cold stress tolerance of plants. To better understand the cold stress tolerance of overseeded perennial ryegrass under TCZ, a three-factor and five-level central composite rotatable design (CCRD) with a regression model was used to study the interactive effects of nitrogen (N), phosphorus (P), and potassium (K) fertilization on lipid peroxidation, electrolyte leakage, reactive oxygen species (ROS) production, and their detoxification by the photosynthetic pigments, enzymatic and non-enzymatic antioxidants. The study demonstrated substantial effects of N, P, and K fertilization on ROS production and their detoxification through enzymatic and non-enzymatic pathways in overseeded perennial ryegrass under cold stress. Our results demonstrated that the cold stress significantly enhanced malondialdehyde, electrolyte leakage, and hydrogen peroxide contents, while simultaneously decreasing ROS-scavenging enzymes, antioxidants, and photosynthetic pigments in overseeded perennial ryegrass. However, N, P, and K application mitigated cold stress-provoked adversities by enhancing soluble protein, superoxide dismutase, peroxide dismutase, catalase, and proline contents as compared to the control conditions. Moreover, N, P, and, K application enhanced chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids in overseeded perennial ryegrass under cold stress as compared to the control treatments. Collectively, this 2-years study indicated that N, P, and K fertilization mitigated cold stress by activating enzymatic and non-enzymatic antioxidants defense systems, thereby concluding that efficient nutrient management is the key to enhanced cold stress tolerance of overseeded perennial ryegrass in a transitional climate. These findings revealed that turfgrass management will not only rely on breeding new varieties but also on the development of nutrient management strategies for coping cold stress.

Magnetic Natural Coagulants for Plastic Recycling Industry Wastewater Treatability

The plastic recycling industry generates a high volume of wastewaters. In this study, an unprecedented use of Moringa oleifera and tannin (Acacia mearnsii bark) associated with magnetite was proposed for the treatment of these wastewaters. The response surface method (RSM) and central composite rotational design (CCRD) methodology was applied to optimize the influence of operational variables (pH, temperature, electrical conductivity, turbidity, apparent color, chemical oxygen demand (COD), and total solids) on the performance of the magnetic natural coagulants on coagulation, flocculation, and sedimentation process. The results indicated that temperature, pH, electrical conductivity, and total solids did not generate significant differences in treatments when magnetite was added to natural coagulants. Similarly, the parameters apparent color, turbidity, and COD also did not present significant differences in treatments with Moringa oleifera and magnetite association, although achieving high efficiencies. Finally, the addition of magnetite significantly improved tannin efficiency removal for turbidity, apparent color, and COD with the optimized treatment (21.55 mg L−1 of tannin concentration and 28 min of sedimentation). Thus, natural coagulants associated with magnetite are potential alternatives for the treatment of plastic recycling wastewater and could be used as an environmentally friendly coagulant.