Response Surface Research Articles

Microwave-assisted selective leaching of valuable metals from spent lithium-ion batteries using glycine and oxalic acid.

Supplying critical metals such as cobalt, lithium, and nickel, to achieve sustainable development goals will be one of the most important concerns in the coming decades. A significant challenge in this area is the separation of some similar elements, such as nickel and cobalt. This study proposes a novel and eco-friendly process to selectively recover cobalt from nickel and manganese. The process includes two leaching stages in a microwave environment: (1) leaching by glycine to separate Ni and Mn and (2) leaching by oxalic acid to separate cobalt from other elements and precipitate it as cobalt oxalate dihydrate. In the first leaching stage, response surface methodology (RSM) was employed to optimize leaching parameters. Under the optimal conditions (3 M of glycine, 0.01 M ascorbic acid, 15 min, pH 9, 500-W microwave power, and a solid-to-liquid (S/L) ratio of 5:100), the average leaching efficiencies were 96.32% for nickel, 91.97% for manganese, and 12.11% for cobalt. In the second leaching stage, 98% of cobalt was successfully precipitated as cobalt oxalate dihydrate by oxalic acid in the microwave environment, with over 87% of the total cobalt ideally recovered from other elements.

Leaching of rare earth elements from phosphogypsum via citric acid medium: optimization through central composite design and kinetics studies.

Due to limited resources of rare earth elements (REEs) and their high demand, these are subjected to supply constraints. So it is important to recover REEs from potential secondary resources. Phosphogypsum is the waste generated on an enormous scale (300 million metric tons per year) from the fertilizer industry. It contains valuable REEs and its disposal has become a major environmental issue. The aim of this research work is to optimize the leaching parameters and determine the kinetics of leaching of REEs from phosphogypsum waste using citric acid. Response surface methodology (RSM) through central composite design (CCD) has been used to assess the influence of three key input variables, i.e., leachant concentration, temperature, and leaching time on the dissolution efficiency of REEs. The results of regression analysis and response surface plots revealed that with the increase in citric acid concentration as well as leaching time, the dissolution ratio of REEs would increase significantly. Under the optimum leaching conditions of 2mol/L citric acid, 343K temperature, and leaching duration of 180min, 90.11% dissolution efficiency was achieved. The kinetics of the leaching was elucidated with the use of shrinking sphere model and was found to be diffusion-controlled. This shows that the high leaching of REEs under moderate conditions is attainable, offering eco-friendly citric acid as a substitute to recover these critical elements from PG waste. The present work tends to develop efficient leaching protocols for the recovery of REEs, which are indispensable raw materials in numerous technological applications.

Using Optimization Techniques on Mechanical Characteristics and Sustainability Assessment of Rubberized Concrete Blended with PVA Fiber Through Response Surface Methodology

The construction sector is promoting eco-friendly materials to combat global warming. Researchers use crumb rubber (CR) in concrete due to its ductility and hardness, but studies show it can decrease strength. Therefore, the addition of PVA fiber improves the mechanical properties of CR concrete. The research aims to assess the mechanical and physical characteristics of concrete by utilizing RSM modeling and optimization, comparing the effects of CR replacement for sand and PVA fiber by volume fraction. It has been observed that the optimum compressive, tensile and flexural strengths were observed by 49 MPa, 4.31 MPa, and 5.88 MPa at 10% of sand replaced with CR and 1.5% of PVA fiber together at 28 days, respectively. In addition, water absorption improves with increased CR and PVA fiber in concrete, while dry density decreases with increased CR and PVA fiber quantity in concrete at 28 days, respectively. Moreover, RSM was utilized to develop response prediction models with R2 coefficients ranged from 97 to 99%. Furthermore, the enhancement of embodied carbon is seen when the volume percent of PVA fiber and CR increases in concrete. Additionally, using 10% CR instead of sand and adding 1.5% PVA fiber has been proven to deliver favourable outcomes for the construction sector therefore it is recommended for construction purpose.

Qualitative and Quantitative Analyses of 1-Aminocyclopropane-1-carboxylic Acid Concentrations in Plants Organs Using Phenyl Isothiocyanate Derivatization.

1-Aminocyclopropane-1-carboxylic acid (ACC) is a direct precursor of phytohormone ethylene. We used a phenyl isothiocyanate (PITC) derivatization modification method combined with spectrographic analysis to isolate and identify three products of the derivatization reactions of ACC and PITC. The MRM+ mode of UPLC-MS/MS was used to establish the analysis of 6-phenyl-5-thioxo-4,6-diazaspiro[2.4]heptan-7-one (PTH-ACC). Three fragment ions detected at the precursor ion (m/z 219.10) were selected for qualitative analysis (m/z 98.10, 77.15, and 72.10), and the most abundant product ion (m/z 98.10) was selected for quantitative analysis. The conditions for the derivatization reaction for the main product PTH-ACC were analyzed and optimized using response surface methodology, resulting in the optimal derivatization conditions being a reaction temperature of 90 °C, a reaction time of 1.5 h, and a formic acid (FA) concentration of 40%. ACC concentrations in 25-200 mg rice samples was successfully determined. Moreover, the ACC concentrations in the shoots, seeds, and roots of rice, maize, and cotton seedlings were all analyzed. The ACC concentrations were found to exhibit tissue specificity. Interestingly, during the ripening process in tomato and mango fruits, the concentrations of ACC in the fruits showed an initial increase, followed by a decrease. In black nightshade fruits, ACC content was the highest in the immature stage, decreased with fruit ripening, and remained stable from the semimature to mature stages. These results provide a reliable analysis technology foundation for the study of ethylene.

Optimization of Extraction Process, Structural Characterization, and Antioxidant and Hypoglycemic Activity Evaluation of Polysaccharides From the Medicinal and Edible Plant: Cistanche deserticola Ma.

Cistanche deserticola Ma (CD), an edible and medicinal plant native to Xinjiang, Inner Mongolia, and Gansu in China, is rich in bioactive polysaccharides known for their health-promoting properties. The polysaccharides of C. deserticola (CDPs) have been shown to possess a range of beneficial activities, including immunomodulatory, anti-aging, antioxidant, and anti-osteoporosis effects. This study seeks to identify the optimal conditions for extracting CDPs using hot water. Additionally, it aims to evaluate their chemical properties, antioxidant activity, hypoglycemic effects, and cytotoxicity. The findings will provide a theoretical foundation for the potential use of CDPs in functional foods and pharmaceuticals. The study employed response surface methodology to optimize the hot water extraction conditions for CDPs. The extracted CDPs were characterized using a range of chemical, spectroscopic, and instrumental analyses. Furthermore, their antioxidant activity, hypoglycemic effects, and cytotoxicity were evaluated through relevant assays to assess their potential health benefits. Under optimal conditions, the yield of CDPs was 45.85% ± 1.91%. CDPs were identified as acidic heteropolysaccharides with a wide molecular weight distribution, ranging from 0.3 to 128.2 kDa. They were composed primarily of glucose (51.21%), arabinose (32.86%), galactose (17.88%), and smaller amounts of galacturonic acid (4.66%), rhamnose (1.85%), mannose (1.32%), glucosamine hydrochloride (1.08%), and xylose (0.56%). Antioxidant assays demonstrated that CDPs exhibited significant free radical scavenging activity, metal ion chelation, and reducing power. Additionally, CDPs inhibited α-glucosidase and α-amylase invitro through a mixed-type mechanism, as well as static fluorescence quenching. Cytotoxicity assays showed that CDPs were nontoxic to L02 and AML12 cells. This study offers a theoretical foundation for the potential use of CDPs in functional foods and pharmaceuticals and provides valuable insights for the development of new antioxidant and hypoglycemic agents from natural sources.

Evaluation and Optimization of physical, mechanical, and biological characteristics of 3D printed Whitlockite/Calcium Silicate composite scaffold for bone tissue regeneration using Response Surface Methodology.

Calcium phosphate (CaP)-based bioscaffolds are used for bone tissue regeneration because of their physical and chemical resemblance to human bone. Calcium, phosphate, sodium, potassium, magnesium, and silicon are important components of human bone. The successful biomimicking of human bone characteristics involves incorporating all the human bone elements into the scaffold material. In this work, Mg-Whitlockite (WH) and Calcium Silicate (CS) were selected as matrix and reinforcement respectively, because of their desirable elemental composition and regenerative properties. The magnesium in WH increases mineralization in bone, and the silicon ions in CS support vascularization. The Mg-Whitlockite was synthesized using the wet chemical method, and powder characterization tests were performed. Response Surface Methodology (RSM) is used to design the experiments with a combination of material compositions, infill ratios, and sintering temperatures. The WH/CS bioceramic composite is 3D printed in three different compositions: 100/0, 75/25, and 50/50 wt%, with infill ratios of 50%, 75%, and 100%. The physical and mechanical characterization study of printed samples is conducted and the result is optimized using RSM. ANOVA (Analysis of Variance) is used to establish the relationship between input parameters and responses. The optimized input parameters were the WH/CS composition of 50/50 wt%, infill ratio of 50%, and sintering temperature of 1150°C, which bring out the best possible combination of physical and mechanical characteristics. The RSM optimized response was a density of 2.27 g/cm3, porosity of 36.74%, wettability of 45.79%, shrinkage of 25.13%, compressive strength of 12 MPa, and compressive modulus of 208.49 MPa with 92% desirability. The biological characterization studies were conducted for the scaffold samples prepared with optimized input parameters. The biological studies confirmed the capabilities of the WH/CS composite scaffolds in bone regenerative applications.&#xD.

Modeling of parameters affecting the removal of chromium using polysulfone/graphene oxide membrane via response surface methodology.

In this study, an efficient membrane composed of polysulfone and graphene oxide was developed and evaluated for its efficacy in chromium adsorption. Characterization of the synthesized membrane involved comprehensive analyses including scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and Fourier-transform infrared spectroscopy (FTIR) to assess its structural properties. Subsequently, the membrane's performance in removing chromium from aqueous solutions was scrutinized, considering key operational parameters. Response surface methodology (RSM) based on central composite design (CCD) was employed to optimize parameters. Additionally, the pH parameter revealed the most significant (F-value = 184.25) on the amount of chromium removal by the membrane process. The interaction between pH and contact time is the most significant among all interactions, with an F-value of 40.99. Moreover, the high R2 (97.58%) and adjusted R2 (95.41%) indicate the model effectively explains variance with minimal overfitting, confirming its strong predictive capability. Under optimized conditions (pH 5, initial concentration of 30 mg/L, and contact time of 40 min), the polysulfone/graphene oxide membrane exhibited an impressive removal efficiency of 81.1%. This study highlights the potential of polysulfone/graphene oxide membranes in effectively separating chromium from aqueous mediums, thereby suggesting a promising avenue for future research in addressing heavy metal pollution.√.

Sustainable biodegradation of malachite green dye by novel non-pathogenic Pseudomonas aeruginosa ED24.

Sustainable management of textile industrial wastewater is one of the severe challenges in the current regime. It has been reported that each year huge amount of textile industry discharge especially the dye released into the environment without pre-treatment that adversely affect the human health and plant productivity. In the present study, different bacterial isolates had been isolated from the industrial effluents and investigated for their bioremediation potential against the malachite green (MG) dye, a major pollutant of textile industries. The biochemical and molecular characterization of the bacterial strain showed the resemblance of most potent strain ED24 as Pseudomonas aeruginosa, which showed effective bioremediation potential against the MG dye. During response surface analysis (RSM), best MG degradation conditions have been observed at pH 7.0, 37°C, 48h, and 200mg/L dye concentration, with highest degradation efficiency of 96.56 ± 0.8622 percent. Subsequently, supplementing various carbon and nitrogen sources increases MG decolorization by 1 to 2%, with beef extract (97.23%), sodium nitrate (97.46%), and maltose (98.67%). FT-IR results revealed the disappearance of distinct peaks, namely, 3328.275cm-1, 2102.842cm-1, 1101.140cm-1,and 559.04cm-1 from MG, and the formation of major intermediate compounds like leucomalachite green, benzoic acid, diacetamide, benzeneacetic acid, hexyl ester, ethyl 4-acetoxy butanoate, butanoic acid, and 2-methyl in GC-MS analysis of degraded dye sample confirms the biodegradation by bacterial strain ED24. The phytotoxicity studies on mung bean seeds confirmed MG dye toxicity reduction up to 67.53%, 54.16%, and 67.53% in biomass accumulation, root, and shoot lengths, respectively. Also, the microbial toxicity of MG was completely reduced on soil microflora Bacillus flexus, Stenotrophomonas maltophilia, Escherichia coli, Staphylococcus aureus, and Alternaria spp.The dual mitigation, both in microbial and plant systems, indicates the strong remediation potential of P. aeruginosa ED24 to break down MG dye ecologically sustainably.

Cellulase from Halomonas elongata for biofuel application: enzymatic characterization and inhibition tolerance investigation

Halophilic bacteria are promising candidates for biofuel production because of their efficient cellulose degradation. Their cellulases exhibit high activity, even in the presence of inhibitors and under extreme conditions, making them ideal for biorefinery applications. In this study, we isolated a strain of Halomonas elongata (Kadal6) from decomposed cotton cloth on a Rameshwaram seashore. Morphological, biochemical, and 16S rRNA analyses revealed that Kadal6 was 99.93% similar to the cellulase-producing strain, H. elongata MH25661. The tolerance of the cellulase to inhibitors was assessed through molecular docking with a cellulase model of MH25661 generated by I-TASSER and experimentally using response surface methodology (RSM) with Kadal6. A molecular docking study indicated a high inhibition constant for ethanol, hydroxymethylfurfural (HMF), and furfural. Cellulase from H. elongata Kadal6 (CellHe) showed a maximum inhibition rate of 44.27% at 55 °C, 15% ethanol, and 6.5 g/L furfural and HMF. The enzyme retained 50% of its activity in the presence of these inhibitors, and remained unaffected at 1 g/L furfural and HMF, although inhibition occurred at 3 g/L. H. elongata cellulase demonstrated significant tolerance to inhibition both in vitro (RSM) and in silico, indicating its potential for biorefinery applications in harsh environments.

Optimization of Leaching of Lithium and Cobalt from Spent Lithium-Ion Batteries by the Choline Chloride-Citric Acid/Malonic Acid DES Using Response Surface Methodology.

Deep eutectic solvents (DESs) are eco-friendly leaching agents which have emerged as potential candidate for recovery of valuable metals from spent LIBs (lithium-ion batteries). Earlier reports show use of more mount of chemicals, long leaching duration and less efficiency. The present work has been carried out to observe the leaching efficiency of two DES-water blend systems such as ChCl:CA(2:1) +30% H2O and ChCl:MA(1:1)+20% H2O for the leaching of Li and Co from cathodic material of spent LIBs using design of experiments and optimization through CCD (central composite design) of Response surface methodology(RSM) approach. Polynomial quadratic model for ChCl:CA (2:1)+35% H2O and the linear model for ChCl:MA(1:1)+20% H2O were selected on the basis statistical parameter values.The physico chemical properties like density, viscosity, conductivity and refractive index of DES-water blend have been determined in the temperature range 298.15 to 328.15K. The influence of temperature, leaching duration and stirring speed on the leaching efficiency has been scrutinized. Cobalt leaching efficiency (99.83%) was higher as compared to that of lithium (96.51%) using citric acid based DES-water blend under the conditions temperature 353 K, leaching time 117 minutes and stirring speed 920 rpm. FTIR and UV-Vis spectra of DES-water blend before and after leaching were recorded. DLS and Zeta potential results confirm higher leaching efficiency of choline chloride-citric acid based DES-water blend.

Optimized hydrothermal carbonization of chicken manure and anaerobic digestion of its process water for better energy management.

Modern poultry production is faced with the challenge of properly managing its associated wastes, in particular chicken manure (CM). There is a need to improve the management of CM through conversion processes that allow the production of value-added products, particularly for energy purposes, such as hydrothermal carbonization (HTC) and anaerobic digestion (AD). The objectives of this study were: i) to optimize the CM-HTC, using response surface methodology with simultaneous optimization of mass yield and higher heating value (HHV), and ii) to evaluate the biomethane potential of the process water generated from hydrochar production under the optimized condition. An analysis of the overall energy potential was also performed. The optimal condition for HTC was 234°C for 30min, resulting in hydrochar with an HHV of 14.88±0.22MJ/kg and a mass yield of 50.00±3.13wt%. The cumulative methane yield was 179.2±13.1 NmL CH₄/g VSadded and 255.5±14.5 NmL CH₄/g VSadded for process water at 180°C and 234°C, respectively. The addition of hydrochar improved the methane yield by 49.6±10.8%, indicating that this is a valuable option for energy recovery from CM. Overall, the HTC-AD integration approach achieved an energy recovery potential of more than 79%, offering an efficient strategy for CM valorization.

Adsorption of perfluorooctanoic acid from aqueous matrices onto chitosan-modified magnetic biochar: Response surface methodology-based modeling, performance, and mechanism.

Perfluorooctanoic acid (PFOA) removal has gained significant attention due to its environmental stability and potential toxicity. This study aims to synthesize a chitosan-modified magnetic biochar (CS_MBC) for efficient PFOA removal from aqueous solutions. Various CS loading ratios (0.25:1, 0.5:1, and 1:1) were explored to determine the optimal adsorbent, with preliminary experiments exhibiting superior performance of CS1_MBC. To explore the impact of various experimental conditions (pH, adsorbent dose, time, and initial PFOA concentrations) on PFOA removal and optimize these parameters, central composite design of response surface methodology was applied. Statistical analysis of variance was conducted to assess the model's adequacy, which demonstrated a strong correlation between experimental results and the model. The predicted optimal conditions for achieving maximum PFOA removal (∼94%) were pH 4, 120mg/L dose, 60min time, and 20mg/L PFOA concentration. The kinetics and isotherm studies revealed that the pseudo-second-order (R2=0.9996) and Redlich-Peterson (R2=0.999) models better described PFOA adsorption, with Langmuir maximum adsorption capacity of ∼517mg/g. Thermodynamic study confirmed the spontaneous, endothermic, and physisorptive nature of PFOA adsorption, with electrostatic and hydrophobic interactions and hydrogen bonding governing the process. Further, the fixed-bed column experiment was conducted to evaluate the effectiveness of CS1_MBC for practical applications, which demonstrated the maximum experimental adsorption capacity of 39.63mg/g. The breakthrough data showed an excellent fit with both the Thomas and Yoon-Nelson models, with a high correlation coefficient (R2=0.99). Therefore, this research underscores the potential of CS_MBC as an efficient adsorbent for mitigating PFOA contamination in aqueous environments.

Elimination of Ni(II) from wastewater using metal-organic frameworks and activated algae encapsulated in chitosan/carboxymethyl cellulose hydrogel beads: Adsorption isotherm, kinetic, and optimizing via Box-Behnken design optimization.

The study investigated the enhancement of stability and efficacy in the removal of bivalent nickel ions (Ni(II)) by utilizing a cerium metal-organic framework (Ce-MOF) encapsulated within a food-grade algal matrix. This composite material is integrated into a dual-layer hydrogel containing chitosan and carboxymethyl cellulose. The enhancement of structural integrity in the final product can be attributed to the cross-linking process with epichlorohydrin, leading to the development of Ce-MOF-FGA/CMC-CS hydrogel beads. A comprehensive characterization of the adsorbent was conducted utilizing various analytical methods. These included X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDX), nitrogen adsorption/desorption isotherm analysis, and field emission scanning electron microscopy (FESEM), all aimed at clarifying the textural characteristics of the material. The investigation also explored the effects of multiple variables, including dosage, pH, temperature, and initial concentration, on the adsorption process. The study conducted equilibrium analyses alongside kinetic evaluations to assess the adsorption characteristics. The results demonstrated that the adsorption behavior aligned with the principles of pseudo-second-order kinetics and was suitably described by the Langmuir isotherm model. The data showing heightened metal adsorption as temperatures increase suggests that the adsorption process is characterized by both endothermic properties and spontaneity. In order to determine the most favorable conditions for adsorption, the Box-Behnken design software was utilized. The findings indicate that the optimal conditions include a pH of 5, a dosage of 0.02 g of Ce-MOF-FGA/CMC-CS hydrogel beads for every 25 mL of solution, and an adsorption capacity of 301.05 mg/g specifically for the Ni(II) solution. To optimize the performance of the adsorbent in the removal of Ni(II) during water purification, it is essential to take into account several key variables. The adsorption efficiency was significantly improved by conducting a series of methodically planned experiments, employing the Box-Behnken design alongside response surface methodology, as supported by Design-Expert software. An in-depth evaluation of the adsorbent's reusability carried out over six successive cycles of adsorption and desorption, indicates a significant stability in its removal efficiency.

Analysis and optimization of threaded shear energy absorbing components of collision resistance hydraulic support columns

Conventional energy-absorbing components have limitations in terms of performance and functionality, including significant variability in reaction forces, inherent instability, and inadequate energy absorption capabilities. This paper presents a threaded shear-type energy-absorbing component designed for anti-impact hydraulic support columns, specifically for ZQL advancing support roadway hydraulic supports. The component operates based on the principle of threaded shear energy absorption. Its key structural parameters—such as thread shape, outer diameter, and pitch—are optimized using single-factor and response surface experimental design methods. Shear simulations are performed to analyze the deformation and force-displacement characteristics across various structural configurations. The impact of different thread parameters on energy absorption performance is evaluated, with quasistatic shear tests and simulations validating the results. The optimized design enhances energy absorption efficiency and provides a foundation for future research on integrating these components into hydraulic support systems to improve overall performance.

Differences in the distribution of steroids in sterol-containing liposomes: A study by liposome electrokinetic chromatography.

This study was conducted to investigate possible differences in the interactions of some selected steroids based on their distribution coefficients with cholesterol- or ergosterol-rich liposomes. Structurally cholesterol and ergosterol have very close resemblance to each other and generally it is thought that they behave in a similar manner. In this work we will show that this is not the case. Liposome electrokinetic chromatography (LEKC) was selected as the methodology for estimating the interactions between the steroids and the liposomes and for calculating the distribution coefficients. Apart from the distribution coefficients, the interactions were also studied with a response surface methodology and exploratory regression analysis. Both graphical and statistical analysis confirmed that there is an obvious difference in the interactions between the studies steroids and the cholesterol- or ergosterol-rich liposomes, and even a minute change in the sterol content had a significant impact on the interactions. The study demonstrates the flexibility and efficacy of LEKC for studying analyte-lipid membrane interactions, and for investigating taylor-made liposome systems.

Composition and antioxidant activity of flavonoids from two different species of Amomi Fructus extracted using natural deep eutectic solvents.

Amomi Fructus, a mature fruit from a ginger family plant, has various species, resulting in inconsistent sourcing and quality. Most studies distinguish species by volatile compounds, yet research shows it also contains flavonoids with notable pharmacological effects. Solely focusing on volatile compounds could lead to considerable resource waste. This study aims to establish flavonoid markers in Amomi Fructus to distinguish its species, assess quality, and promote efficient resource use. Utilizing natural deep eutectic solvents (NADES) and response surface methodology (RSM), an optimal extraction system (choline chloride-ethylene glycol) yielded 41.38mg RE/g total flavonoids. LC-MS analysis of 18 Amomi Fructus batches identified 26 flavonoids, quantified 19, and highlighted three key markers-epicatechin, procyanidin B2, and procyanidin B4-that effectively differentiate Amomum villosum Lour. (AMV) from Amomum villosum Lour. var. xanthioides T.L. Wu et Senjen (AMVX). Finally, flow cytometry confirmed these markers' antioxidant activity, effectively reducing H₂O₂-induced oxidative damage in GES-1 cells.

Optimization of ultrasound-assisted enzymatic hydrolysis Zophobas morio protein and its protective effects against H2O2-induced oxidative stress in RAW264.7 cells.

Zophobas morio protein (ZMP) is a promising protein resource with notable biological properties, and its hydrolysis could unlock enhanced bioactivities. This study investigated ultrasound-assisted enzymatic hydrolysis (UAEH) of ZMP using different enzymes (Alcalase, Neutrase, and Protamex) to determine its effect on the degree of hydrolysis (DH) compared to enzymatic hydrolysis (EH). UAEH showed greater hydrolysis efficiency than EH, with Alcalase exhibiting the highest DH. Response surface methodology (RSM) was applied to optimize UAEH conditions for Zophobas morio protein hydrolysate (ZMPH). Optimal conditions for producing ZMPH with the maximum DH were a substrate concentration of 3.52 % (w/v), enzyme to substrate ratio of 7.64 % (v/v), and pH of 8.35. Under the optimal condition, the maximum DH was 25.03 %. In addition, significant structural changes in the optimized ZMPH compared to ZMP were identified, showing decreased α-helix and β-sheet content, with increased β-turn and unordered coil. Moreover, the optimized ZMPH demonstrated significantly improved ABTS antioxidant activity and attenuated H2O2-induced cell death in RAW264.7 cells compared to ZMP, which was attributed to better mitigation of ROS production. These findings provide an effective enzymatic hydrolysis method for producing ZMPH with significant antioxidant activity, demonstrating the potential of ultrasound-assisted hydrolysis in enhancing the bioactivity of insect proteins.

Optimization of Culture Medium Ingredients and Culture Conditions for Bacteriocin Production in Lactococcus lactis NCU036019.

Bacteriocin lactococcin036019 was identified and characterized from Lactococcus lactis NCU036019, which displayed significant antibacterial activity toward foodborne pathogenic bacteria Staphylococcus aureus under various conditions. However, the in situ low-level expression of lactococcin036019 severely limited its wide application in food industry. In this study, we optimized the medium ingredients and culture conditions of L. lactis NCU036019 for maximum production of lactococcin036019. The effects of different carbon sources, nitrogen sources, inorganic salts, growth factors, surfactants, and buffer salts on the production of bacteriocin were studied using antibacterial titer and diameter of inhibitory zone as evaluation indexes. Through single-factor experiments, Plackett-Burman (PB) experiment, steepest ascent experiment and response surface methodology, yeast extract, zinc sulfate, sodium acetate, mannitol, Tween-80, and dipotassium hydrogen phosphate were identified to display significant influence on the production of bacteriocin. By optimizing Man Rogosa and Sharpe (MRS) culture medium ingredients, the antibacterial activity of lactococcin036019 in the cell-free supernatant raised from 46.19 to 300.14Au/mL, namely, 6.5 times increased. Furthermore, the culture conditions, such as inoculation amount, culture time, and culture temperature, were optimized, and this further increased the antibacterial activity to 409Au/mL, namely, 8.8 times increased. This study investigated the effects of culture media and conditions on the production of lactococcin036019, and they were optimized for a maximum harvest of bacteriocin, and the significant increase of bacteriocin production in L. lactis NCU036019 facilitates the application of the antibacterial substance in future work.

Optimization of fermentation conditions to increase the production of antifungal metabolites from Streptomyces sp. KN37

The bacterium Streptomyces sp. KN37 was isolated from the soil of Kanas, Xinjiang. The broth dilution of strain KN37 has a strong inhibitory effect against a variety of crop pathogenic fungi. However, in practical applications, its effective biological activity is limited by medium formulations and fermentation conditions. In this study, we used the response surface method to optimize the fermentation medium and conditions of the strain KN37, for investigating the reasons for the enhanced biological activity at both the metabolic and transcriptomic levels. The results of the Plackett-Burman design showed that millet, yeast extract, and K2HPO4 were the key factors influencing its antifungal activity. Subsequently, optimization by the response surface methodology yielded the final fermentation conditions as: millet 20 g/L, yeast extract 1 g/L, K2HPO4 0.5 g/L, rotation speed 150 r/min, temperature 25 °C, initial pH 8, fermentation time 9 d, inoculation amount 4%, liquid volume 100 mL. The antifungal effect of the optimized strain fermentation dilution was significantly enhanced, and the antifungal rate of R. solani increased from 27.33 to 59.53%, closely aligning with the predicted value of 53.03%. The results of HPLC-MS/MS and transcriptomic analysis revealed that the content of some secondary metabolic active substances in the fermentation broth of KN37 was significantly different from that of the original fermentation broth. Notably, the content of 4- (diethylamino) salicylaldehyde (DSA) was significantly increased by 16.28-fold while the yield of N- (2,4-dimethylphenyl) formamide (NDMPF) was increased by 6.35 times. Transcriptomic analysis further elucidated molecular mechanisms behind these changes with the expression of salicylic acid dehydrogenase (SALD) was significantly down-regulated, which was only 0.48 times compared to that before optimization. This research successfully optimized the fermentation process of strain KN37 providing a strong foundation for the actual production and application of strain KN37 in agriculture.

Microencapsulation using spray drying of anthoxyanins from Lannea microcarpa (African grape) fruits juice with pyrodextrin from sweet potato starch

Anthocyanins rich fruits of Lannea microcarpa (African grape) with antioxidant activity are an important food and herbal medicine in central Africa. This study sought to use response surface methodology to optimize spray drying microencapsulation of anthocyanins from L. microcarpa fruit juice, examining the influence of inlet air temperature (120—150 °C), inlet air flow rate (60—80 m3/h) and carrier agent (pyrodextrin) concentration (8 -16 g/100 g of juice), on various spray-dried powders characteristics. Moreover, the thermal stability study of L. microcarpa fruit juice powder produced at optimal process conditions was studied. The linear effect of inlet air temperature, inlet air flow rate and carrier agent concentration significantly affected the fruit powder properties (Moisture content, hygroscopicity, encapsulation efficiency) (P < 0.05), except in the case of hygroscopicity where linear effect of inlet air temperature did not. The optimum spray drying conditions to obtain the encapsulated fruit juice powder were determined as 150°C inlet air temperature, 80 m3/h inlet air flow rate and 9 g/100 g carrier agent concentration. The optimal spray dried juice powder was produced with a product yield of 72.4%, water activity of 0.281, having a poor flowability but high cohesiveness. Dynamic Vapor Sorption analysis showed sorption isotherm fitted GAB and BET models well and lower water activity (aw < 0.5) at 25 °C could be favorable for storage of L. microcarpa powders. Additionally, the stability study shown according to the degradation rate obtained that encapsulated fruit juice powder stored at 25 C exhibited greater stability with rate constant k = 0.0018 day-1 significantly lower than the same spray dried L. microcarpa juice powder stored at 35°C (k = 0.0035 day-1) (p < 0.05). These results demonstrate microencapsulation through spray drying using pyrodextrin from sweet potato was feasible for enhancing the stabilization of anthocyanins in form of powder with potential application in food and chemical industries.Graphical