Response Surface Optimization Research Articles

Modal analysis and optimization design of ultra-high acceleration platform rail frame

The ultra-high acceleration macro and micro motion platform has the advantages of high positioning accuracy and small error, and the key mechanism rail frame of the ultra-high acceleration macro and micro motion platform is optimized based on modal analysis to achieve the performance optimization of the platform. SolidWorks software was used to build the rail frame model, and ANSYS Workbench software was used to carry out modal analysis, topology optimization and response surface optimization, etc., so as to reduce the quality of the rail frame as much as possible under the premise of maintaining the stability of the first-order natural frequency. The results show that the optimization of the response surface meets the expected goal, the first-order natural frequency of the guide rail frame increases by 0.7 %, the mass decreases from 6.165 kg to 5.592 kg, and the change rate is 9.2 %, which achieves the purpose of lightweight.

Tyrosinase Inhibitory Peptide from the Hydrolysates of Eel Bone: Optimization of Preparation, Inhibition Kinetics and Molecular Docking

ABSTRACT The main purpose of this study was to discover new tyrosinase inhibitory peptides from eel bone hydrolysates. After enzyme screening, alkaline protease was utilized, and optimal conditions were achieved through response surface optimization: solid-liquid ratio (1:25), time (5 h), and enzymolysis base ratio (3500 U/g). Inhibitory peptides of 1–3 kDa were isolated (IC50 = 2.162 mg/mL), and the inhibition was determined to be non-competitive and reversible. Subsequent LC-MS/MS and molecular docking revealed that the peptide with the lowest binding energy exhibited hydrogen bonding, hydrophobic interactions, and provided a potential explanation for the mechanism of inhibition by the peptides.

Optimisation of fermentation condition for production of hight monacolin k (mk) yield by monascus-strains

Monacolin K (MK), produced by Monascus fermentation, has significant hypolipidemic effects. In this study, under solid-state fermentation (SSF) quinoa was used as substrate to investigate the effect of the MK production by Monascus species quinoa. The results of the single factor experiment showed that the amount of the substrate loaded, addition of water to the substrate, and fermentation temperature change time have a significant effect on the MK production of Monascus-fermented quinoa. It was found that neither M. pilosus-fermented quinoa nor M. ruber-fermented quinoa produced citrinin. Consequently, these three factors were selected for the response surface optimization to determine the optimal fermentation process. The results showed that the optimal fermentation process of M. pilosus-fermented quinoa was as follows: quinoa loading amount of 30 g/300 ml, addition of 20 ml water to substrate, seed liquid inoculation volume of 10%, cultured at 30°C for 2 days, followed by a temperature change to 25°C and continued cultivation until 12 days. Under this fermentation process, the yield of MK reached 2.51 mg/g and without production of any citrinin. The optimal fermentation process of M. ruber-fermented quinoa was as follows: quinoa loading amount of 31 g/300 ml, water addition of substrate of 20 ml, seed liquid inoculation volume of 20%, cultured at 30°C for 2 days, followed by a temperature change to 25°C and continued cultivation until 12 days. Under this fermentation process, the yield of MK reached 3.22 mg/g and without any citrinin production. Bangladesh J. Bot. 53(3): 717-729, 2024 (September) Special

Response surface optimization of protein extraction from cold-pressed terebinth (Pistacia terebinthus L.) oil byproducts: Physicochemical and functional characteristics.

The current study focused on optimizing the extraction parameters of terebinth seed proteins from cold-pressed terebinth oil byproducts to maximize protein purity and protein yield. The isolated proteins were characterized to evaluate their properties; thus revealing the valorization potential of these byproducts. Response surface methodology was used to detect the effect of three extraction parameters (pH, temperature, and time). The protein isolates were studied for their physicochemical and functional characteristics. The results indicated that an extraction pH of 8, a temperature of 50°C, and an extraction period of 60min are optimum conditions for obtaining protein isolates with the highest purity. On the other hand, it was demonstrated that an extraction pH of 12, a temperature of 46.4°C, and an extraction duration of 102.4min were optimum conditions for the maximum protein yield. The proteins produced under these two sets of conditions, referred to as TRP (terebinth protein with maximum purity)and TRY (terebinth protein with maximum yield), respectively, exhibited comparable oil absorption capacity (OAC), foaming, emulsifying capabilities, and stability. Both proteins showed the highest solubility at pH 11, and their zeta potentials approached zero at pH 4, indicating proximity to their isoelectric points. However, FRAP and DPPH assays showed that TRP and TRY offered low antioxidative capacity. The high β-sheet content in TRP and TRY suggests enhanced thermal stability but reduced digestibility of these proteins. Therefore, in addition to protein enrichment, TRP and TRY protein isolates can be utilized in muffins and other food applications thanks to their favorable oil absorption, foaming and emulsifying capacities, and thermal stabilities.

Catalytic performance of FeCo2O4 spinel cobaltite for degradation of ethylparaben in a peroxymonosulfate activation process: Response surface optimization, reaction kinetics and cost estimation

The presence of cosmetics and personal care products in water resources has become an increasing concern for environment due to their toxicity and persistence in aquatic medium. Peroxymonosulfate mediated advanced oxidation methods have a great potential for the efficient removal of complex organic compounds due to the generation of highly reactive radicals with high oxidation ability. Iron cobaltite, FeCo2O4 catalyst was used as a peroxymonosulfate (PMS) activator for the degradation of ethylparaben which was selected as a model personal care product ingredient. Paraben degradation was modelled and the optimum operating parameters were determined by using Box-Behnken design. The ethylparaben degradation efficiency was calculated as 94.6 % under the optimized conditions which were determined as 0.9 g/L FeCo2O4 loading, pH 6.15, and 0.26 g/L PMS dosage. The ethylparaben degradation reaction followed second-order reaction kinetics. The activation energy was evaluated as 40.1 kJ/mol. Quenching radical tests showed that the dominant reactive species were hydroxyl radicals. Toxicity of the treated samples in terms of L. sativum growth inhibition was evaluated as 1.5 %. The total cost of the treatment including the operating and the amortization costs was calculated as 0.91 €/L.

Response surface optimization of a single-step castor oil-based biodiesel production process using a stator-rotor hydrodynamic cavitation reactor.

In order to combat environmental pollution and the depletion of non-renewable fuels, feasible, eco-friendly, and sustainable biodiesel production from non-edible oil crops must be augmented. This study is the first to intensify biodiesel production from castor oil using a self-manufactured cylindrical stator-rotor hydrodynamic cavitation reactor. In order to model and optimize the biodiesel yield, a response surface methodology based on a 1/2 fraction-three-level face center composite design of three levels and five experimental factors was used. The predicted ideal operating parameters were found to be 52.51°C, 1164.8rpm rotor speed, 27.43min, 8.4:1 methanol-to-oil molar ratio, and 0.89% KOH concentration. That yielded 95.51% biodiesel with a 99% fatty acid methyl ester content. It recorded a relatively low energy consumption and high cavitation yield of 6.09 × 105J and 12 × 10-3g/J, respectively. The generated biodiesel and bio-/petro-diesel blends had good fuel qualities that were on par with global norms and commercially available Egyptian petro-diesel. The preliminary cost analysis assured the feasibility of the applied process.

Bionic Optimization Design and Fatigue Life Prediction of a Honeycomb-Structured Wheel Hub.

The wheel hub is an important component of the wheel, and a good hub design can significantly improve vehicle handling, stability, and braking performance, ensuring safe driving. This article optimized the hub structure through morphological aspects, where reducing the hub weight contributed to enhanced fuel efficiency and overall vehicle performance. By referencing honeycombed structures, a bionic hub design is numerically simulated using finite element analysis and response surface optimization. The results showed that under the optimization of the response surface analytical model, the maximum stress of the optimized bionic hub was 109.34 MPa, compared to 119.77 MPa for the standard hub, representing an 8.7% reduction in maximum stress. The standard hub weighs 34.02 kg, while the optimized hub weight was reduced to 29.89 kg, a decrease of 12.13%. A fatigue analysis on the optimized hub indicated that at a stress of 109.34 MPa, the minimum load cycles were 4.217 × 105 at the connection point with the half-shaft, meeting the fatigue life requirements for commercial vehicle hubs outlined in the national standard GB/T 5334-2021.

Enhancing horticultural harvest efficiency: The role of moisture content in ultrasonic cutting of tomato stems

Ultrasonic vibration has notable benefits in the harvesting and processing of tomato stems, particularly in reducing cutting force and minimizing moisture loss. Given the anisotropic nature of biological materials, the moisture content of tomato stems significantly impacts their physical properties. This study investigates the influence of varying moisture content on temperature and cutting force during the ultrasonic cutting of tomato stems. Initially, the moisture content of tomato stems at different maturity stages was measured using a water activity meter. Mechanical properties were characterized using a universal testing machine, and thermal properties were analyzed with a differential scanning calorimeter (DSC). Regression models were established to correlate moisture content with these material properties. Additionally, a three-dimensional microscopic model of stem skeletons, interfaces, and fiber bundles was created to simulate the fracture mechanisms during ultrasonic cutting under different moisture levels. Single-factor and response surface optimization experiments were conducted using a custom experimental setup under varying maturity stages, excitation frequencies, and voltage variations. Results showed that after 24 h, the peak temperatures for tomato stems at different maturity stages were 97.84 °C, 80.59 °C, and 74.15 °C, with corresponding cutting forces of 0.492 N, 0.544 N, and 0.998 N, respectively. The discrepancy between experimental results and simulation data was within 10 %. Higher moisture content was found to enhance the thermal conductivity of fiber materials, aiding in the fracture of fiber bundles, thus reducing cutting time and force. This study provides a theoretical foundation for the application of ultrasonic technology in the efficient harvesting and processing of industrial crops, with significant implications for horticultural crop treatment and processing.

Study on the adsorption mechanism of ciprofloxacin in wastewater by modified fly ash under the coexistence of copper

The recontamination of farming wastewater with antibiotics and metal ions has emerged as a considerable concern in recent years. In this study, fly ash (FA) served as the adsorbent material, and its modified form (AFA) was developed via response surface optimization. The study involved an analysis of the structure and chemical composition of the fly ash before and after modification, both pre- and post-modification, through the use of scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR) analyses. These analyses were aimed at exploring the adsorption mechanism of ciprofloxacin (CIP) in the presence of copper ion (Cu2+) in livestock and poultry wastewater. The study indicates that the optimal modification parameters for AFA include an alkali-to-ash ratio of 1.5, a calcination temperature of 400 °C, and a 3-hour calcination period. At pH 6, AFA exhibited a markedly superior adsorption capacity for CIP in comparison to FA, with AFA achieving 19.32 mg/g and FA only 9.61 mg/g. The adsorption process conforms to the quasi-second-order kinetic model and Langmuir isothermal model.The adsorption capacity for CIP increases at low concentrations, specifically when Cu2+ levels are below 100 mg/L. Nevertheless, elevated CIP concentrations impede the adsorption process. The adsorption of AFA for CIP is observed to decrease with rising temperature, in contrast to the adsorption of Cu2+, which increases as the temperature rises. The adsorption mechanism of AFA is primarily comprised of pore filling, ion exchange, electrostatic interaction, π bond coordination, complexation, and other similar processes.

Sustainable ferritin from bovine by-product liver as a potential resource: Ultrasound assisted extraction and physicochemical, structural, functional, and stable analysis

Ferritin is an iron-containing protein that is widely present in all organisms and has the function of regulating the metabolic balance of iron in organisms. It can be separated from animal by-product tissues and converted into value-added components to promote the development of a circular economy. This study established a method for extracting bovine liver ferritin (BLFer) using ultrasound-assisted buffer system. The optimal extraction conditions were determined through single factor and response surface optimization experiments as follows: ultrasound temperature of 70 °C, extraction time of 25 min, ultrasonic power of 400 W and solvent-to-solid ratio of 2 mL/g, the experimental value of the ferritin yield was 32.18 ± 0.12 g/kg. Compared with traditional methods, Ultrasound-assisted extraction improved the ferritin yield and enhanced its structural stability. Bioinformatics analysis revealed that BLFer is a hydrophilic protein with strong thermal stability. The BLFer has a ferrous oxidase active center, which plays an important role in the oxidative precipitation and reductive release of iron. It can dissociate under strong acids or bases but maintains good stability after heat treatment. These findings will help improve the comprehensive utilization of animal by-products, and promote the potential application of animal by-product ferritin in food and other industries.

Improved black-winged kite algorithm and finite element analysis for robot parallel gripper design

This paper presents a comprehensive study on the design optimization of a robotic gripper, focusing on both the gripper modeling and the optimization of its parallel mechanism structure. This study integrates the Black-winged Kite Algorithm (BKA), Finite Element Analysis (FEA), Backpropagation Neural Network (BPNN), and response surface optimization techniques. The Good Point Set (GPS), nonlinear convergence factor, and adaptive t-distribution method improve BKA, which enhances exploration and exploitation performance, convergence speed, and solution quality. Subsequently, the parallel mechanism structure is designed to minimize the total mass, total deformation, and maximum equivalent stress. The central composite design (CCD) method was used to design the FEA experiment and establish the BKA-BPNN regression prediction model. The RMSE of this model’s training set and test set are 0.001615 and 0.0029328. A response surface optimization model is constructed to determine the best design solution. The optimized design achieves a 33.12% reduction in maximum equivalent stress, a 1.47% decrease in total mass, and a 0.16% reduction in maximum total deformation. This study provides valuable insights into the design optimization process for robotic grippers, showcasing the effectiveness of the proposed methodologies in enhancing performance while reducing mass and improving structural integrity.

Multi-Objective Optimization of a Novel Gas-Liquid Cylindrical Cyclone Based on Response Surface Methodology

Currently, most major oilfields in China have reached a stage of high water content, where the extracted fluid is often accompanied by significant volumes of associated gas. This situation increases extraction costs and elevates safety risks. To address these challenges, this paper presents an innovative redesign of the traditional gas-liquid cylindrical cyclone (GLCC) by applying composite mechanics to improve the inner cone structure. The new design is tailored for conditions with high gas content and flow rates. Using response surface optimization, the optimal structural parameters for the separator were identified: an inlet area of 881 mm2, a column diameter of 110mm, and an inner cone height of 189mm. Furthermore, the study integrates numerical simulation with experimental research to compare and analyze the flow characteristics and separation performance of the GLCC before and after optimization. The results demonstrate that the optimized GLCC achieves a separation efficiency of 93.2%, an improvement of 21.2 percentage points over the initial design, with a maximum pressure loss of 0.0621MPa. The experimental findings and numerical simulations show strong agreement, confirming the efficacy of the new design.

Multi-objective optimization of a triple-eccentric butterfly valve considering structural safety and sealing performance

The structural safety and sealing performance of a triple-eccentric butterfly valve are crucial technical indicators that influence its reliability and service life. In this study, a new multi-objective optimization strategy is proposed to realize a lightweight design of valve trims, reduce the maximum equivalent stress, and reasonably distribute the sealing-specific pressure. A two-stage optimization scheme is designed by combining topology optimization (TO) and response surface methodology optimization (RSM). The topology optimization is employed to allocate the material distribution of the valve trims and provide the parameters for the response surface optimization, while the response surface methodology optimization conducts a further revision and optimization of the structural parameters of the valve trims. The results of the simulation experiments indicate that the maximum equivalent stress of the lightweight designed valve trims is reduced from 290.85 MPa to 99.88 MPa, and the maximum sealing-specific pressure of the sealing surface is reduced from 197.78 MPa to 77.83 MPa. Additionally, a novel approach is presented for assessing the sealing performance using the clearance of the fitting surface. This method can intuitively evaluate the state of metal sealing and guide the design of the fitting tolerance by analyzing the sensitivity of the dimensional deviation to the sealing-specific pressure. The findings demonstrate that the optimized valve exhibits good structural safety and sealing performance.

Response Surface Optimization of the Extraction Process and the Antioxidant Capacity of Total Flavonoids from Microcos Paniculata L.

Ultrasonic-microwave synergistic method was used to extract the total flavonoids from Microcos Paniculata L. To optimize the extraction process, we have conducted single-factor experiments on the total flavonoids yield to provide a basis for analysis. After the results were evaluated, we carried out the response surface method to test the antioxidant properties of total flavonoids in Microcos Paniculata L. The evaluation of antioxidant capacity was done from four dimensions. According to the experiments, the optimal extraction parameters included: 40 mesh particle size, 20:1 liquid/feed ratio (mL/g), 250 W ultrasonic power, 400 W microwave power, 30 min extraction time, and a 60% volume fraction of ethanol. When all the conditions were met, the yield of total flavonoids from Microcos Paniculata L. could reach 6.01%. The total flavonoids from Microcos Paniculata L. could remove DPPH.and ABTS+. At the same mass concentration, the scavenging rates. were as high as 93.14% and 84.40%, respectively. They were close to the scavenging rates of Vc in the positive control group. This proves that the total flavonoids in Microcos Paniculata L. have a good antioxidant ability.

Quality by Design (QbD) Approach to Develop Colon-Specific Ketoprofen Hot-Melt Extruded Pellets: Impact of Eudragit® S 100 Coating on the In Vitro Drug Release.

A pelletizer paired with hot-melt extrusion technology (HME) was used to develop colon-targeted pellets for ketoprofen (KTP). Thermal stability and side effects in the upper gastrointestinal tract made ketoprofen more suitable for this work. The pellets were prepared using the enzyme-triggered polymer Pectin LM in the presence of HPMC HME 4M, followed by pH-dependent Eudragit® S 100 coating to accommodate the maximum drug release in the colon by minimizing drug release in the upper gastrointestinal tract (GIT). Box-Behnken Design (BBD) was used for response surface optimization of the proportion of different independent variables like Pectin LM (A), HPMC HME 4M (B), and Eudragit® S 100 (C) required to lower the early drug release in upper GIT and to extend the drug release in the colon. Solid-state characterization studies revealed that ketoprofen was present in a solid solution state in the hot-melt extruded polymer matrix. The desired responses of the prepared optimized KTP pellets obtained by considering the designed space showed 1.20% drug release in 2 h, 3.73% in the first 5 h of the lag period with the help of Eudragit® S 100 coating, and 93.96% in extended release up to 24 h in the colonic region. Hence, developing Eudragit-coated hot-melt extruded pellets could be a significant method for achieving the colon-specific release of ketoprofen.

Response surface optimization for supercritical carbon dioxide extraction of Korarima (Aframomum corrorima) seed oil and its antibacterial activity evaluation

Oils extracted from natural plants are valuable resources because of their diverse biocidal activity against microorganisms. This paper reports, for the first time, supercritical CO2 extraction of oil from Korarima (Aframomum corrorima) seeds and its antibacterial activity evaluation. The influences of pressure, temperature, and extraction time on the yield of supercritical CO2-extracted oil (scCO2-extracted oil) were optimized using the Response Surface Methodology. Under the optimal extraction conditions of 46 °C, 15.5 MPa, and 147 min, the extraction yield reached 1.60±0.04 %, consistent with the theoretical value of 1.58 %. The compositions of the scCO2-extracted oil were identified by GC-MS, primarily consisting of nerolidol (33.97–41.20 %), geraniol (23.08–24.50 %), and α-terpinene (8.90–9.06 %). The oil exhibited significant antibacterial activity against Staphylococcus. aureus with a minimum inhibitory concentration of 1 mg·mL−1. This study highlights the potential applications of supercritical CO2 extraction technology for extracting Korarima seed oil and its use as an antibacterial ingredient in cosmetics and pharmaceuticals.

Novel Bioplastic Based on PVA Functionalized with Anthocyanins: Synthesis, Biochemical Properties and Food Applications.

Over the last ten years, researchers' efforts have aimed to replace the classic linear economy model with the circular economy model, favoring green chemical and industrial processes. From this point of view, biologically active molecules, coming from plants, flowers and biomass, are gaining considerable value. In this study, firstly we focus on the development of a green protocol to obtain the purification of anthocyanins from the flower of Callistemon citrinus, based on simulation and on response surface optimization methodology. After that, we utilize them to manufacture and add new properties to bioplastics belonging to class 3, based on modified polyvinyl alcohol (PVA) with increasing amounts from 0.10 to 1.00%. The new polymers are analyzed to monitor morphological changes, optical properties, mechanical properties and antioxidant and antimicrobial activities. Fourier transform infrared spectroscopy (FTIR) spectra of the new materials show the characteristic bands of the PVA alone and a modification of the band at around 1138 cm-1 and 1083 cm-1, showing an influence of the anthocyanins' addition on the sequence with crystalline and amorphous structures of the starting materials, as also shown by the results of the mechanical tests. These last showed an increase in thickening (from 29.92 μm to approx. 37 μm) and hydrophobicity with the concomitant increase in the added anthocyanins (change in wettability with water from 14° to 31°), decreasing the poor water/moisture resistance of PVA that decreases its strength and limits its application in food packaging, which makes the new materials ideal candidates for biodegradable packaging to extend the shelf-life of food. The functionalization also determines an increase in the opacity, from 2.46 to 3.42 T%/mm, the acquisition of antioxidant activity against 2,2-diphenyl-1-picrylhdrazyl and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) radicals and, in the ferric reducing power assay, the antimicrobial (bactericidal) activity against different Staphylococcus aureus strains at the maximum tested concentration (1.00% of anthocyanins). On the whole, functionalization with anthocyanins results in the acquisition of new properties, making it suitable for food packaging purposes, as highlighted by a food fresh-keeping test.

Chitosan/Sodium Alginate Hydrogel for the Release of Berberine as an Algae Suppressant: RSM Optimization and Analysis of Sustained Release Characteristics.

In this study, we used chitosan/sodium alginate hydrogel as a carrier to prepare berberine sustained-release capsule materials that can inhibit algae for a long time and safely. The preparation conditions of the material were optimized by the response surface method, and the optimized capsule material was characterized and the sustained release characteristics were analyzed to study the change of the algae inhibition effect of the material within 30 days. The results showed that the optimum preparation parameters of the material were 0.54% chitosan content, 2.46% sodium alginate content and 1.09% anhydrous calcium chloride content by response surface optimization design, which was consistent with the parameters set by each factor at the central point. The algae inhibition rate of the material under this preparation condition was 93.75 ± 1.01%, which was similar to the predicted value. The release characteristics analysis showed that the material continuously released up to 90% of berberine within 24 days, and its release characteristics were sustained release after burst release, with good sustained release effect. The results of material characterization showed that chitosan/sodium alginate hydrogel could effectively load berberine and was beneficial to the loading and release of berberine. The results of algae inhibition experiments showed that low concentration materials could control the outbreak of cyanobacterial blooms in a short time, while under high concentration conditions, the materials could inhibit Microcystis aeruginosa efficiently and for a long time.

Radiofrequency affects the decrystallization efficiency and physicochemical properties of rape honey via crystal structure modification and inactivating enzyme

Crystallization degrades the physicochemical properties of honey and reduces consumer acceptance. To address this issue, radiofrequency was developed to investigate the decrystallization efficiency and quality impact mechanism of rape honey. The results showed that radiofrequency significantly decreased the number and size of crystals, leading to shortening the decrystallization time to less than 10 min. The response surface optimization methodology further indicated that the highest decrystallization rate (98.72 ± 0.34 %) and lower 5-Hydroxymethylfurfural (2.45 ± 0.12 mg/kg) contents were obtained. Furthermore, radiofrequency changed the honey from a pseudoplastic into a Newtonian fluid efficiently due to the volumetric heating feature. It is worth noting that the inactivation of glucose oxidase reduced the antibacterial capacity, while the increase in total phenolic and flavonoid contents improved the antioxidant capacity of rape honey. In summary, current findings indicated that radiofrequency is a potential alternative decrystallization technology for water baths.

Research on the Cell Wall Breaking and Subcritical Extraction of Astaxanthin from Phaffia rhodozyma.

This study focused on developing an effective cell wall-breaking method for Phaffia rhodozyma, followed by utilizing subcritical fluid extraction to isolate, extract, and concentrate astaxanthin from the complex fermentation products of P. rhodozyma. A comprehensive comparison of seven distinct methods for disrupting cell walls, including dimethyl sulfoxide treatment, lactic acid treatment, sodium hydroxide treatment, β-glucanase enzymatic digestion, β-mannanase enzymatic digestion, and a combined enzymatic treatment involving both β-mannanase and β-glucanase was conducted. The results identified the lactic acid method as the most effective in disrupting the cell walls of P. rhodozyma. The software, Design Expert, was used in the process of extracting astaxanthin from cell lysates using a subcritical extraction method. Through fitting analysis and response surface optimization analysis by Design Expert, the optimal extraction conditions were determined as follows: an extraction temperature of 41 °C, extraction frequency of two times, and extraction time of 46 min. These parameters facilitated the efficient extraction, concentration, and enrichment of astaxanthin from P. rhodozyma, resulting in an astaxanthin concentration of 540.00 mg/L. This result can establish the foundation for its high-value applications.