Plackett-Burman Research Articles

Aspergillus awamori MK788209 cellulase: production, statistical optimization, pea peels saccharification and textile applications

BackgroundThe demand for low-cost cellulolytic enzyme synthesis is rising in the enzyme market. This work aims to produce cellulase by utilizing various agricultural wastes and investigating the use of enzyme in saccharification and textile industries.ResultsSolid state fermentation (SSF) was applied to produce industrial enzymes, particularly cellulase, through utilizing Molokhia (Corchorus olitorius) stems by Aspergillus awamori MK788209 isolate. Two stages of statistical factorial designs Plackett-Burman (PB) and Central Composite Design (CCD) were applied to enhance the A. awamori MK788209 cellulase production from Molokhia stems (MS). The fold increase of enzyme production by PB followed by CCD was 2.51 and 4.86, respectively. Additionally, the A. awamori MK788209 culture filtrate was highly effective in saccharifying various agricultural wastes, particularly pea peels (PP) (yielding 98.33 mg reducing sugar/ml), due to its richness in cellulase, laccase, xylanase, pectinase, and amylase. By optimizing the three main variables; pea peel weight, culture filtrate volume added, and saccharification time by CCD, the sugar recovery from PP was enhanced, leading to a 3.44-fold increase in reducing sugar recovery (338 mg reducing sugar /ml). Furthermore, the A. awamori MK788209 culture filtrate showed high efficacy in textile applications, enhancing the roughness, weight loss, white index, and printing capability of treated cotton fabrics.ConclusionsA. Awamori MK788209 produced cellulase which was effective in PP saccharification. The enzyme was also capable of enhancing cotton fabric properties.

Response surface methodology for rapid removal of an azo dye methyl orange by indigenous bacterial strain (Bacillus cereus J4)

Sulfonated azo dyes like Methyl Orange (MO) are widely used in industries such as textiles, paper, food, and printing, but their discharge into wastewater poses a serious threat to aquatic life. This study aimed to isolate and optimize bacterial strains for the bioremediation of MO from textile effluents. Eleven bacterial strains were isolated from industrial effluents in Panipat, India, with Bacillus cereus J4 demonstrating the highest decolorization efficiency, removing up to 98% of MO within 48 hours. To optimize the decolorization process, two methods were employed Plackett–Burman (PB) design and Response Surface Methodology (RSM). PB design identified significant factors affecting decolorization, while RSM provided a more comprehensive optimization by considering interactions among factors. RSM reported an optimal removal rate of 89.8% MO at 50 mg/l dye concentration, pH 7, 37°C, and 2% urea. In conclusion, Bacillus cereus J4 showed promising potential for MO bioremediation under optimized conditions. Future studies should explore scaling up the process and examining the strain’s effectiveness on other industrial dyes to develop a broad-spectrum bioremediation strategy.

Design and two step process optimization of a reactive distillation column for improving production amount of ethyl acetate and water

In this study, two step optimization was performed for operating conditions of a reactive distillation (RD) column using simulation outputs. The effects of the operating parameters of the RD column, on the ethyl acetate (EtAc) amount as a result of the reaction between ethanol (EtOH) and acetic acid (HAc) were assessed. The response surface methodology (RSM) was applied to determine the optimum operating conditions for the RD column. The two step experimental design used in RSM was created with the Design Expert (DE) program. The Plackett-Burman (PB) design was used to determine the most important parameters affecting on the designed RD column for production of EtAc amount. The most important parameters were determined as HAc feed rate (kmol/h), EtOH feed rate (kmol/h), reflux ratio and temperature (°C). After PB design Central Composite Design (CCD) was applied to determine the optimum operating conditions of these most important parameters for the RD column. ANOVA was used to investigate the interaction between the response and independent variables with the obtained data and 3 dimensional (3D) plots created by the program were interpreted. A second order regression model according to the independent variables for the EtAc amount (response) was developed with DE program. The optimum operating conditions for the designed RD column were obtained as HAc feed rate 149.86 kmol/h, EtOH feed rate 99.99 kmol/h, feed temperature 70 °C and reflux ratio 2.50. The production of EtAc amount which determined with model coefficients and recommended by the program were compared and relative errors between the model results and the predicted values were less than 1%. The obtained results were showed that RSM may be a suitable method for optimization of operating parameters in RD columns.

Adsorptive removal of Congo Red dye from its aqueous solutions by tetraethylenepentamine modified peanut husks composite beads

The ability of tetraethylenepentamine modified peanut husks (TEPA-PH) composite beads in the removal of an anionic azo dye, Congo Red (CR) was studied. In batch adsorption studies, various parameters such as contact time, initial dye concentration, pH, dosage and agitation rate were included to study their influence towards the adsorption process. The TEPA-PH composite beads formed were thoroughly characterized by using several techniques which includes Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy, Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The experimental data followed the pseudo-second-order kinetic model with R2 close to unity. Among the isotherm models, the experimental data is best fitted to Freundlich isotherm model by having R2 of 0.9948. The maximum adsorption capacity was determined to be 19.5695 mg/g using the Langmuir model. The significant factors were selected using the Plackett-Burman (PB) design and the optimization of the adsorption model was done using the Response Surface Methodology (RSM). With optimum conditions of 180 min of contact time, 62.5 mg/L of initial dye concentration and 0.35 g of dosage, the percentage uptake of CR can reach 77.11%.

Calibration and experimental verification of discrete element parameters for modelling feed pelleting

The discrete element method (DEM) has demonstrated significant advantages in modelling feed-tool interaction. The selection of an appropriate contact model and its parameter calibration is crucial for developing effective DEM simulations. A DEM model of feed powder was developed to forecast powder compression and densification in feed pelleting by using the Edinburgh elasto-plastic adhesion contact model. Firstly, a calibration method of DEM parameters based on the Plackett–Burman (PB) and the central composite (CC) test was proposed to enhance calibration efficiency. Both experimentally and through DEM simulation of the uniaxial confined compression experiments, powder repose angle experiments, and powder static friction angle experiments were used to calibrate the DEM parameters. Extract the DEM parameters that have a significant impact on feed pelleting through PB testing. Then, the effects of these parameters on response were analysed using CC testing, and ascertain their optimal values. Finally, the single-hole open compression experiment and feed pelleting experiment were used to evaluate the accuracy of the parameters. The results show that the average relative error between the predicted ultimate compressive force in the open compression experiment and the measured value is 8.16%, and that of the torque of the pellet mill is 2.10%. Thus, it was shown that the modelling and calibration method can effectively predict the compression and densification of powder in the feed pelleting.

Optimization Design of the Elbow Inlet Channel of a Pipeline Pump Based on the SCSO-BP Neural Network

A vertical pipeline pump is a type of single-stage, single-suction centrifugal pump with a curved elbow input. The inhomogeneous flow of the impeller inlet coexists with the unique elbow inlet channel, making it simple to generate the inlet vortical secondary flow. This paper aimed to optimize elbow inlet channel performance using a backpropagation (BP) neural network enhanced by the Sand Cat Swarm algorithm. The elbow flow channel’s midline and cross section shapes were fitted with a spline curve, and the parametric model of the curve was then constructed. Nine initial variables were filtered down to four optimization variables using the partial factor two-level (P2) and Plackett-Burman (P-B) experimental designs and multivariate analysis of variance. The sample space was generated by 50 groups of experiment samples, and the Sand Cat Swarm algorithm to optimize the BP (SCSO-BP) neural network and the approximation model of four variables were built. A genetic algorithm (GA) was applied to determine the optimal parameters among the approximate models in the sample space, and the ideal parameter combination of the elbow inlet channel was achieved. The findings demonstrated a strong agreement between the experimental and numerical simulation results. With reduced error fluctuation in inaccuracy and a more consistent fluctuation range, the approximate prediction model based on the optimized Sand Cat Swarm algorithm performed better. The optimized inlet model minimized the impact loss on the inlet wall, improved the velocity distribution uniformity of the inlet impeller, increased the pump efficiency by about 5% and the head by about 7.48% near the design flow, and broadened the efficient region of the pump.

Interfacial coupling efficiency of functionalised rubbers on silica surfaces

Understanding filler-polymer interactions at the interfaces is an important aspect for rubber reinforcement development. Recent technology in the field of silica-rubber reinforcement has led to an increasing interest in functionalised rubbers, since they can directly react and enhance interactions with silica filler, and hence improved rubber reinforcement. The present work aims to better understand the role of different reaction variables, i.e. time, temperature, rubber concentration, solvent, surfactants, sonication, specific surface area of silica, rubber type, and catalyst, on rubber deposition on silica surface in a model reaction in solution of silica and functionalised rubbers. Results from the Design of Experiments (DoEs) study, i.e. One-Factor-At-a-Time (OFAT), Plackett-Burman (P-B) and Full-Factorial (FF) designs showed that all studied factors have a negligible effect on interfacial coupling efficiency of rubber to silica surface. Accessibility of the functional groups at the rubber molecules and the steric hindrance due to large polymeric molecular chains seem to be the most limiting factors, resulting in low coupling efficiency. Effects of the investigated reaction parameters and plausible mechanisms involved in rubber-silica coupling reactions are elucidated.

Calibration of Model Parameters for Soda Saline Soil-Subsoiling Component Interaction Based on DEM

To apply the discrete element method (DEM) to simulate the interaction process between soda saline–alkali soil and subsoiling component in Northeast China, establishing the soda saline–alkali soil particle model and selecting more accurate simulation parameters are important. In this paper, we studied the soda saline–alkali soil of the Songnen Plain in China. First, we studied the geometric shape of soda saline–alkali soil particles and proposed a modeling method for single soil particles based on the multisphere combination method. Considering the cohesion of soda saline–alkali soil particles, the Hertz–Mindlin with JKR (JKR) model was used as the contact model between soil particles. Then, the calibration method was used to obtain simulation parameters of soils that are difficult to obtain experimentally. We conducted soil angle of repose (AoR) tests, the Plackett–Burman (PB) tests, and steepest ascent (SA) tests in turn to perform a sensitivity analysis for microscopic contact parameters and select the parameters that have a significant effect on the response value (static AoR), i.e., soil surface energy, soil–soil static friction coefficient, and soil–soil rolling friction coefficient. Then, the optimal combination of simulation parameters was obtained via the Box–Behnken (BB) tests, using ANOVA to optimize the multiple regression equation. Finally, the optimal parameter combination was verified by the AoR test and the direct shear (DS) test. The results showed that the parameters had good adaptability for the AoR test. However, the simulation results of the DS test were significantly different from the experimental values. Therefore, the contact model needs to be further modified by adding Bonding bonds between soil particles based on the JKR model and further correcting for Rayleigh time step, shear modulus, and surface energy. By comparing the simulation and the experimental results, it was found that the simulation results obtained from both the DS test and AoR test had relatively small errors relative to physical tests, the two trends are the same, and the values are similar. This verified the feasibility and effectiveness of the soda saline–alkali soil particle modeling method and parameter selection proposed in this paper.

Ellipsoidal seed modeling and simulation parameter selection based on the discrete element method

At present, there are still some issues in the discrete element modeling of non-spherical agricultural materials. For example, it is still necessary to enrich and optimize the particle model of non-spherical granular materials and study their simulation parameters. Therefore, in this paper, ellipsoidal seeds, such as those of soybeans, red beans, and kidney beans, were taken as the research object, and their dimensions and shapes were analyzed. The results showed that the dispersion in size could be approximated by a normal distribution. An approach for modeling ellipsoidal seeds as particles based on the multi-sphere (MS) method was proposed. Moreover, the Plackett–Burman (PB) test and the path of the steepest ascent method were both adopted to calibrate the simulation parameters, which were obtained with difficulty through experiments, and simulations of the piling test and the rotating hub test for calibration to ensure the rationality of the parameter selection. In addition, to improve the reliability of the calibration test, the automatic filling function in EDEM software was adopted for particle modeling, where the smoothness was 2. A 122-sphere model for the soybean seed, a 114-sphere model for the red bean seed, and a 242-sphere model for the kidney bean seed were established, and the three models were applied for the calibration of the simulations of the tests. The results showed that the coefficients of rolling friction between seeds had a significant influence on the simulation results for the three varieties of seeds. Finally, the manual filling models and the automatic filling models were further verified by using simulations of bulk density tests. Comparing the simulation and experiment results showed that when the number of filling spheres increased, the simulation results were closer to those obtained experimentally. Better simulation accuracy could be obtained with fewer filling spheres. These results could provide a reasonable discrete element model and simulation parameters for further simulation and optimization of designs of seeding machinery for ellipsoidal seeds.

Production of 2,3-Butanediol by S. cerevisiae L7 in Fed-Batch Fermentation with Optimized Culture Conditions

As a chemical platform, 2,3-Butanediol (2,3-BD) has been widely applied in various industrial fields. In this study, to enhance the production of 2,3-BD by Saccharomyces cerevisiae L7, Plackett–Burman (PB) multifactorial design, the steepest climb test and central composite design (CCD) were employed to optimize the culturing conditions of S. cerevisiae L7. The results show that acetic acid, peptone and glucose were contributing factors for 2,3-BD production. Subsequently, a satisfactory production of 2,3-BD (13.52 ± 0.12 g/L) was reached under optimal conditions, which was 3.12 times higher than before optimization. Furthermore, fed-batch fermentation was carried out under optimized culture conditions, and a higher production and yield efficiency of 2,3-BD were achieved (21.83 ± 0.56 g/L and 0.15 ± 0.01 g/g, respectively) when glucose (20 g/L) and acetic acid (0.2 g/L) were added at 12, 24, 36, 48 and 60 h. Therefore, the production and yield efficiency of 2,3-BD were higher than those without fed-batch fermentation (61.46% and 58.51%, respectively). These results provide good support and a technical foundation for the large-scale industrial production of 2,3-BD by Saccharomyces cerevisiae.

Optimization of fermentation, purification and properties of blue pigment produced from Quambalaria cyanescens QY229.

Blue pigments have broad applications in foods, cosmetics, and clothing. However, natural blue pigments are rare. At present, the majority of blue pigments for sale are chemically synthetic. Owing to the safety risks of chemical pigments, it is an urgent demand to develop novel natural blue pigments. The fermentation medium and culture conditions of blue pigment produced by Quambalaria cyanescens QY229 were optimized by Plackett-Burman (PB) experimental design and response surface methodology (RSM) for the first time. The stability, bioactivity and toxicity of the obtained blue pigment were studied after isolation and purification. The results showed that the optimal fermentation parameters were 34.61 g·L-1 of peptone concentration, 31.67°C of growing temperature, and 72.33mL of medium volume in a 250mL flask, and the yield of blue pigment reached 348.2±7.1 U·mL-1. QY229 blue pigment is stable to light, heat, pH, most metal ions and additives, and has certain antioxidant and inhibitory activity of α-glucosidase in vitro. QY229 blue pigment at concentrations of 0-1.25mg·mL-1 was nontoxic to Caenorhabditis elegans in an acute toxicity trial.

Statistical modeling and safety analysis for developing design resistance of deconstructable HSFGB shear connectors in composite beam

In recent years, the high-strength friction-grip bolt (HSFGB) shear connectors in steel-concrete composite beams as deconstructable connectors are of great research interest since they are aligned with sustainable construction. However, the design strength equation for this type of connector has not yet been provided by the design codes such as AISC and Eurocode 4. In this paper, with regard to the reliability aspect, the design strength equation of HSFGB shear connectors is investigated which is projected into a partial safety factor according to Eurocode 4. Accordingly, the three-dimension finite element (FE) push-out model of the composite connection is developed and verified via experimental results to predict the load-slip behavior and failure modes in this type of bolted shear connector. Then One-Factor-at-a-Time (OFAT) method as a sensitivity analysis and Plackett-Burman (PB) design method as a screening analysis are utilized to identify the effective factors of the ultimate strength of HSFGB connectors. Finally, based on a complete database of all existing experimental findings, the results obtained from 55 three-dimension finite element models conducted in this paper, and appropriate statistical analysis, a high-precision equation for predicting ultimate strength is provided. Then the value of the partial safety factor is determined through a reliability study in accordance with EN1990, which provides an acceptable level of safety for the proposed design equation based on Eurocodes. Reliability analysis found that a partial factor of 1.52 was justified for the design strength of HSFGB connectors, which differed from the partial factor of 1.25 stated in the EC for welded stud shear connectors.

Bidirectional fermentation of Monascus and Mulberry leaves enhances GABA and pigment contents: establishment of strategy, studies of bioactivity and mechanistic

Bidirectional fermentation is a technology that utilizes fungi to ferment medicinal edible substrates, with synergistic and complementary advantages. In this work, a fermentation strategy was established to produce a high yield of γ-aminobutyric acid (GABA) and Monascus pigments (MPs) using Monascus and mulberry leaves (MLs). Firstly, the basic fermentation parameters were determined using single-factor experiments, followed by Plackett-Burman (PB) experimental design to identify MLs, glucose, peptone, and temperature as significant influencing factors. The fermentation parameters were optimized using an artificial neural network (ANN). Finally, the effects of bidirectional fermentation of MLs and Monascus were investigated by bioactivity analysis, microstructure observation, and RT-qPCR. The outcomes showed that the bidirectional fermentation significantly increased the bioactive content and promoted the secondary metabolism of Monascus. The established fermentation conditions were 44.2 g/L of MLs, 57 g/L of glucose, 15 g/L of peptone, 1 g/L of MgSO4, 2 g/L of KH2PO4, 8% (v/v) of inoculum, 180 rpm, initial pH 6, 32 °C and 8 days. The content of GABA reached 13.95 g/L and the color value of MPs reached 408.07 U/mL. This study demonstrated the feasibility of bidirectional fermentation of MLs and Monascus, providing a new idea for the application of MLs and Monascus.

Characterization of green peppers based on dynamic repose angle

Virtualization of machining process, is of great significance, for the design and research of equipment to improve food quality and safety. Green pepper (GP), a biological origin fruit, displays promising cosmetic, spices and drug values, but its processing is labor and time intensive, which urgently needs equipment to improve productivity. Therefore, this investigation taking the dynamic angle of repose obtained from rotating drum assays as indicator, to explore suitable material and interaction properties for the discrete element method (DEM) to re-produce the processing visually. Primarily, ranges of these properties were experimentally measured. Centrally, values of these properties were categorized and reasonably determined via a set of simulations involving the Plackett-Burman (PB), Steepest Ascent (SA), and Central Combination Design (CCD). Interestingly, the PB demonstrated that coefficients of static friction between particle-steel (CoSP−s) and coefficients of friction and restitution between particle-particle (CoRP−P; CoSP−P; CoLP−P) were significant, their optimal ranges (0.59–0.64, 0.15–0.30, 0.20–0.44, 0–0.05) and values (0.590, 0.299, 0.200, 0.034) were sequentially selected by the SA and CCD respectively. Collectively, suitable properties were determined as the selected and mean values of the significant and insignificant properties, respectively. Importantly, values of these properties have been confirmed via triplicate independent verification simulations.

Identifying markers volatiles in Brazilian virgin oil by multiple headspace solid-phase microextraction, and chemometrics tools

A protocol was optimized to determine the volatile profile from monovarietal virgin olive oil (VOO) by multiple headspace solid-phase microextraction (MHS-SPME) followed by gas chromatography-mass spectrometry (GC–MS) analysis. For this, a Plackett-Burman (PB) and central composite rotational designs (CCRD) were used to define the best condition of extraction. Moreover, fatty acids profile and principal component analysis (PCA) was used to identify markers among the cultivars. The amount of 0.1 g of sample was enough to express the volatile composition of the olive oils by MHS-SPME. Volatile compounds [nonanal, (Z)-3-Hexen-1-ol, (Z)-3-Hexenyl Acetate, Hexyl Acetate, 3-Methylbutyl Acetate, (E)-2-Hexen-1-ol, (E)-2-Hexenyl Acetate] and fatty acids [C17:1, C18, C18:1, C18:2] were those reported such as the markers in the varieties of olive oils. The PCA analysis allowed the classification of the most representative volatiles and fatty acids for each cultivar. Through two principal components was possible to obtain 81.9% of explanation of the variance of the compounds. The compounds were quantified using a validated method. The MHS-SPME combined with multivariate analysis showed a promising tool to identify markers and for the discrimination of olive oil varieties.

Complementary spectroscopy studies and potential activities of levan-type fructan produced by Bacillus paralicheniformis ND2

This study aimed at the production of marine bacterial exopolysaccharides (EPS) as biodegradable and nontoxic biopolymers, competing the synthetic derivatives, with detailed structural and conformational analyses using spectroscopy techniques. Twelve marine bacterial bacilli were isolated from the seawater of Mediterranean Sea, Egypt, then screened for EPS production. The most potent isolate was identified genetically as Bacillus paralicheniformis ND2 by16S rRNA gene sequence of ~99 % similarity. Plackett-Burman (PB) design identified the optimization conditions of EPS production, which yielded the maximum EPS (14.57 g L−1) with 1.26-fold increase when compared to the basal conditions. Two purified EPSs namely NRF1 and NRF2 with average molecular weights (Mw¯) of 15.98 and 9.70 kDa, respectively, were obtained and subjected for subsequent analyses. FTIR and UV–Vis reflected their purity and high carbohydrate contents while EDX emphasized their neutral type. NMR identified the EPSs as levan-type fructan composed of β-(2–6)-glycosidic linkage as a main backbone, and HPLC explained that the EPSs composed of fructose. Circular dichroism (CD) suggested that NRF1 and NRF2 had identical structuration with a little variation from the EPS-NR. The EPS-NR showed antibacterial activity with the maximum inhibition against S. aureus ATCC 25923. Furthermore, all the EPSs revealed a proinflammatory action through dose-dependent increment of expression of proinflammatory cytokine mRNAs, IL-6, IL-1β and TNFα.

Optimization and cholesterol-lowering activity of exopolysaccharide from Lactiplantibacillus paraplantarum NCCP 962

Exopolysaccharides (EPSs) are biological polymers with unique structural features have gained particular interest in the fields of food, chemistry and medicine, and food industry. EPS from the food-grade lactic acid bacteria (LAB) can be used as a natural food additives to commercial ones in the processing and development of functional foods and nutraceuticals. The current study was aimed to explore the EPS-producing LAB from the dahi; to optimize the fermentation conditions through Plackett-Burman (PB) and response surface methodology (RSM); and to study its physicochemical, rheological, functional attributes, and cholesterol-lowering activity. Lactiplantibacillus paraplantarum NCCP 962 was isolated among the 08 strains screened at the initial stage. The PB design screened out four independent factors that had a significant positive effect, i.e., lactose, yeast extract, CaCl2, and tryptone, while the remaining seven had a non-significant effect. The RSM exhibited lactose, yeast extract, and CaCl2, significantly contributing to EPS yield. The maximum EPS yield (0.910g/L) was obtained at 6.57% lactose, 0.047% yeast extract, 0.59% CaCl2, and 1.37% tryptone. The R2 value above 97% explains the higher variability and depicts the model's validity. The resulted EPS was a heteropolysaccharide in nature with mannose, glucose, and galactose monosaccharides. FTIR spectrum reflected the presence of functional groups, i.e., O-H, C-H, C = O, C-O-H, and CH2. SEM revealed a porous and rough morphology of EPS, also found to be thermally stable and negligible weight loss, i.e., 14.0% at 257°C and 35.4% at 292.9°C was observed in the 1st and 2nd phases, respectively. Rheological attributes revealed that strain NCCP 962 had high viscosity by increasing the EPS concentration, low pH, and temperature with respectable water holding, oil capacities, foaming abilities, and stability. NCCP 962 EPS possessed up to 46.4% reduction in cholesterol concentration in the supernatant. Conclusively, these results suggested that strain NCCP 962 can be used in food processing applications and other medical fields. KEY POINTS: • The fermentation conditions affect EPS yield from L. paraplantarum and significantly increased yield to 0.910g/L. • The EPS was heteropolysaccharide in nature and thermally stable with amorphous morphology. • Good cholesterol-lowering potential with the best rheological, emulsifying, and foaming capacities.

Optimization, fractional characterization, and antioxidant potential of exopolysaccharides from Levilactobacillus brevis NCCP 963 isolated from "kanji".

A novel exopolysaccharide (EPS) was obtained from Levilactobacillus brevis NCCP 963 isolated from a black carrot drink named "kanji". The culture conditions for maximum EPS yield were explored by the Plackett-Burman (PB) design and response surface methodology (RSM) along with the fractional characterization and antioxidant potential of EPSs. The PB design screened out five significant factors, namely, glucose, sucrose, tryptone, CaCl2, and di-potassium phosphate out of eleven independent factors. The RSM indicated glucose and CaCl2 as significant factors in EPS production and a maximum EPS production of 968.89 mg L-1 was obtained at optimized levels of 10.56% glucose, 9.23% sucrose, 0.75% tryptone, 0.446% CaCl2, and 0.385% K2HPO4. A R2 value above 93% indicates higher variability, depicting the validity of the model. The obtained EPS has a molecular weight of 5.48 × 104 Da and is a homopolysaccharide in nature with glucose monosaccharides. FT-IR analysis showed significant band stretching of C-H, O-H, C-O and C-C and indicated the β-glucan nature of EPSs. The comprehensive antioxidant investigation showed significant in vitro DPPH, ABTS, hydroxyl, and superoxide scavenging capacity with EC50 values of 1.56, 0.31, 2.1, and 6.7 mg mL-1 respectively. Curd formation from the resulting strain prevented syneresis.

Optimization of xylanase production from Aspergillus Spp. hau-f-6 using plackett burman screening design and path of steepest ascent in submerged fermentation

Optimization of xylanase production from Aspergillus Spp. hau-f-6 using plackett burman screening design and path of steepest ascent in submerged fermentation

Effect of Substrate Composition on Yield and Antioxidative Activity of Exopolysaccharides From Lactobacillus fermentum B62

Abstract Exopolysaccharides (EPS) can not only give food a unique texture but also has antioxidant capacities. To select the medium composition that influences the yield and antioxidative activity of EPS, Plackett–Burman (PB) design was employed to appraise the effects of carbon sources, nitrogen sources, and inorganic salts on yield and DPPH free radical scavenging (DPPH-FRS) rate of EPS in MRS medium fermented by Lactobacillus fermentum B62. The result indicated that sucrose (p<0.01), peptone (p<0.01), and KH2PO4 (p<0.001) had the most distinguishing comprehensive effects on yield and DPPH-FRS rate of EPS, and fructose also had a noticeable effect on the two factors (p<0.05, p<0.001, respectively). Additionally, glucose (p<0.05), soy protein (p<0.001), yeast extract (p<0.01), KH2PO4 (p<0.001) and Ca(H2PO4)2 (p<0.001) significantly positive affect the yield of EPS. And inulin (p<0.05), tryptone (p<0.001), beef extract powder(p<0.001), NaH2PO4 (p<0.01) and C2H3NaO2 (p<0.05) significantly positive affect the DPPH-FRS rate of EPS. Within the test ranges, sucrose, fructose, peptone and KH2PO4 all showed significant positive relativity to the yield and anti-oxidative activity of EPS.