Central Composite Statistical Design Research Articles

Statistical optimization for comparative hydrolysis and fermentation for hemicellulosic ethanolgenesis

The concept of ‘Energy from waste’ is one of the most focused areas of work to find a solution for controlling trash and combat energy crises. In Pakistan and other agricultural countries, because of their substantial use during the summer, watermelon peels as fruit waste are usually thrown out as a trash. This study supported the management of huge quantities of waste to value-added products at a commercial scale. The current study aims to select and subject xylanolytic and ethanologenic Bacillus cereus XG2 for watermelon peels valorization appropriately with comparison of three hydrolysis techniques. The study will be helpful for selection of economical and environmentally beneficial valorization strategies. For ethanalogenesis, separate hydrolysis and fermentation (SHF) protocols with Saccharomyces cerevisiae K7 and Metchnikowia cibodasensis Y34 were used. For hydrolysis, three different saccharification approaches, viz. dilute sulfuric acid, enzymatic hydrolysis (using Bacillus cereus XG2 xylanases), and combined acidic and enzymatic hydrolysis, were adopted. Two statistical models, Placket-Burman (hydrolysis) and Central composite design (ethanologenesis) were used. In untreated watermelon waste (WW), reducing sugar, total lipids, total carbohydrates, and protein contents were calculated as 16.70±0.05 g/L, 3.20±0.02 g/L, 28.7±0.04 g/L, and 3.70±0.03 g/L, respectively. Similarly, the lignin (15.51±0.22%), hemicellulose (17.20±2.30%). and cellulose (52.26±0.33%) contents were also analyzed. Based on the significance of the Plackett–Burman model for enzymatic saccharification, the released reducing sugars as well as total sugars were 21.62±0.01 g/L and 43.30±1.55 g/L, respectively, and enzymatic hydrolyzate was adopted for further fermentation experiments. By CCD model, the highest ethanol yield calculated for yeast Metchnikowia cibodasensis Y34 was 0.4±0.04 g/g of fermentable sugars at 32.5oC with 50% enzymatic hydrolysate of WW by incubating for 8 days. It was suggested that SHF could be a beneficial approach to increase the conversion of hemicellulose to fermentable sugars to produce bioethanol on a large scale.

Environmental – Solar thermal effects a long-term on the efficiency of amorphous climate-resilient mortar using a central composite design application

The objective of this investigation is to evaluate the durability of dune sand mortar containing display e-glass waste (DEGW) in severe Saharan environments, chemical attacks, or other factors that can cause cementitious materials to deteriorate at long- term. The aim is to use DEGW powder as a partial replacement for dune sand in various mortar mixtures and assess the performance of hardened mortar in terms of ultrasonic pulse velocity, dynamic elasticity modulus, compressive strength, and flexural strength and sportivity. The study also examines the influence of the curing period and different climatic conditions in curing environments, such as those in Algeria's Sahara region. The Response Surface Methodology (RSM) was used to adjust the e-waste glassy mortar, with the statistical tool Central Composite Design (CCD) approach. The hydration of cement compounds was monitored using differential thermal analysis (DTA), thermogravimetric analysis (TGA), Differential Scanning Calorimetry (DSC), and X-ray diffraction (XRD). The DEGW was replaced in 5% increments from 0% to 20%. The results showed that the glassy dune sand mortar exhibited the highest properties at 20% incorporation after 365 days of severe climatic conditions. The feasibility of the proposed quadratic model was recommended for the five responses by RSM, in which the coefficient of determination (R2) ranges from 0.93 to 0.97, showing the model’s high significance. For structural display e-glassy dune sand mortar, display glass E-waste can replace 20% of dune sand, which improves all durability and environmental sustainability. Furthermore, the DSC, TGA / DTA results and XRD analysis showed that the < 0.08 mm class exhibited good pozzolanic behaviour, and the specimens significantly improved as curing periods increased.

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.

Advancements in biodigester technology through the study of anaerobic digestion using statistical optimization and bioaccelerators

AbstractAdvances in biodigester technology have been promoted by the growing study of anaerobic digestion, with the aim of improving processes related to the utilized waste load. This research used the statistical tool Central Composite Rotatable Design to optimize the combination of microorganisms and enzymes for biodigestion. The experiment involved testing two microorganisms (EA and EB) and five enzymes (amylase, protease, lipase, cellulase, and amyloglucosidase) with food waste from nearby restaurants and WWTP sludge as an inoculant. The experiment was set up as Central Composite Rotatable Design (CCRD) 26‐1, with 50 trials and a concentration of 14.5 g of volatile solids per liter. The dependent variables of cumulative biogas production (BG) and cumulative biomethane production (BM) were evaluated. The results showed that the independent variables EB and CA had negative and significant effects on BG and BM production. With optimized process conditions, the bioaccelerator significantly improved BG and BM responses compared to control trials by 72% and 88%, respectively. The biodigestion technique is a viable option for the treatment of organic waste, and the use of bioaccelerators may be a promising approach to improving biodigestion processes. This study contributes to the ongoing research on anaerobic digestion and biodigester technology, which seeks to improve the sustainable management of organic waste while producing renewable energy.

Influence of filler/cement and powder/total solids on the mixture design of self-compacting micro-concretes containing waste from the ornamental stone industry

The present work evaluated the effects of incorporating high volumes of waste from the processing of ornamental stones as fillers in self-compacting micro-concretes, considering physical–chemical, mechanical, microstructural and eco-efficiency results. A particle packing method assisted in the mix designs, and the experimental program followed a central composite rotational statistical design. Response surfaces and desirability analyses showed that the residue has a good packing function, filler effect, heterogeneous nucleation and workability, in addition to being effective in reducing the embodied CO2, delivering matrices more eco-efficient for conventional mechanical strengths.

Statistical optimization, characterization, antioxidant and antibacterial properties of silver nanoparticle biosynthesized by saw palmetto seed phenolic extract

On the global market, silver nanoparticles (Ag-NPs) are in high demand for their various applications in biomedicine, material engineering, and consumer products. This study highlighted the biosynthesis of the Ag-NPs using saw palmetto seed phenolic extract (SPS-phenolic extract), which contained vital antioxidant-phenolic compounds. Herein, central composite statistical design, response surface methodology, and sixteen runs were conducted to optimize Ag-NPs biosynthesis conditions for maximizing the production of Ag-NPs and their phenolic content. The best-produced SPS-Ag-NPs showed a surface plasmon resonance peak at 460 nm and nano-spherical sizes ranging from 11.17 to 38.32 nm using the UV spectrum analysis and TEM images, respectively. The produced SPS-Ag-NPs displayed a high negative zeta-potential value (− 32.8 mV) demonstrating their high stability. The FTIR analysis demonstrated that SPS-phenolic compounds were involved in sliver bio-reduction and in stabilizing, capping, and preventing Ag-NP aggregation. The thermogravimetric investigation revealed that the produced SPS-Ag-NPs have remarkable thermal stability. The produced SPS-Ag-NP exceeded total antioxidant activity (13.8 µmol Trolox equivalent) more than the SPS-phenolic extract (12.0 µmol Trolox equivalent). The biosynthesized SPS-Ag-NPs exhibited noticeably better antibacterial activity against multidrug-resistant Gram-negative E. coli and Gram-positive S. aureus compared to SPS-phenolic extract. Hence, the bio-synthesized SPS-Ag-NPs demonstrated great potential for use in biomedical and antimicrobial applications.

Optimization of the Green Extraction of Red Araçá (Psidium catteyanum Sabine) and Application in Alginate Membranes for Use as Dressings.

In this research, the aim was to introduce innovation to the pharmaceutical field through the exploration of an underutilized plant matrix, the red araçá, along with the utilization of sodium alginate for the development of membranes designed for active topical dressings. Within this context, optimal extraction conditions were investigated using the central composite rotational statistical design (CCRD) to obtain a red araçá epicarp extract (RAEE) rich in bioactive compounds utilizing the maceration technique. The extract acquired under the optimized conditions (temperature of 66 °C and a hydroalcoholic solvent concentration of 32%) was incorporated into a sodium alginate matrix for the production of active membranes using a casting method. Characterization of the membranes revealed that the addition of the extract did not significantly alter its morphology. Furthermore, satisfactory results were observed regarding mechanical and barrier properties, as well as the controlled release of phenolic compounds in an environment simulating wound exudate. Based on these findings, the material produced from renewable matrices demonstrates the promising potential for application as a topical dressing within the pharmaceutical industry.

FORMULATION DEVELOPMENT AND OPTIMISATION OF FAST DISSOLVING BUCCAL FILMS LOADED GLIMEPIRIDE SOLID DISPERSION WITH ENHANCED DISSOLUTION PROFILE USING CENTRAL COMPOSITE DESIGN

Objective: This study aimed to enhance the solubility and dissolution of Glimepiride, a new-generation hypoglycaemic agent with low water solubility, by preparing Fast dissolving buccal films (FDBFs) containing Glimepiride solid dispersion. Methods: Glimepiride solid dispersions were fabricated using Polyethylene Glycol 4000 as the carrier by Physical mixture, Solvent evaporation, Kneading, and Fusion method. The optimised solid dispersion was selected based on the drug content and in vitro dissolution data. The final films incorporated with solid dispersion were prepared by the solvent casting technique, wherein the film formulation was optimised using the design of experiment (DoE) approach by applying the Central Composite statistical design. The optimised film formulation was then evaluated for various parameters, including weight variation, folding endurance, disintegration time, thickness, surface pH, and dissolution studies. Results: Among the different methods employed, the kneading method using PEG 4000 in a drug-to-polymer ratio of 1:3 exhibited the highest drug content and in vitro drug release, making it the most promising option. The film formulation that was optimised displayed an accelerated in vitro drug dissolution within a time frame of 10 min, with an average disintegration time of 31.33±0.471. Conclusion: The developed FDBFs loaded with Glimepiride solid dispersion demonstrated a markedly improved dissolution profile, avoidance of extensive first-pass metabolism, and improved patient compliance. The results suggest that the developed FDBFs could be a potential alternative to conventional dosage forms of Glimepiride.

Mineralization of Industrial Wastewater by a Hybrid Technique of Adsorption (Fe3O4@AC Nanocomposite) + Heterogeneous Fenton + Sonication and Discernment of Synergistic Effects

This paper reports investigations in the mineralization of industrial wastewater (COD = 3246 mg/L, TOC = 2500 mg/L) using a ternary (ultrasound + Fenton + adsorption) hybrid advanced oxidation process. Fe3O4 decorated activated charcoal (Fe3O4@AC) nanocomposites (surface area = 538.88 m2/g; adsorption capacity = 294.31 mg/g) were synthesized using coprecipitation. The wastewater treatment process was optimized using central composite statistical design. At optimum conditions, viz. pH = 4.2, H2O2 loading = 0.71 M, adsorbent dose = 0.34 g/L, reduction in COD and TOC of wastewater were 94.75% and 89%, respectively. These results are attributed to synergistic interactions between the adsorption of pollutants on Fe3O4@AC, surface Fenton reactions, and enhanced mass transfer due to sonication. This synergism boosted the interactions among •OH radicals and pollutant molecules, leading to effective degradation and mineralization. The Fe3O4@AC showed excellent recovery (>90 wt %) and reusability (>90% COD removal) in 5 successive cycles of treatment.

Co-delivery of doxorubicin and paclitaxel via noisome nanocarriers attenuates cancerous phenotypes in gastric cancer cells

Gastric cancer (GC) is known as a deadly malignancy all over the world, yet none of the current therapeutic regimens have achieved efficacy. this current study has aimed to optimize and reduce treatment doses and overcome multidrug resistance in GC by developing optimum niosomal formulation for the delivery of doxorubicin (DXR), paclitaxel (PTX), and their co-delivery. The particles' size, polydispersity index (PDI), and entrapment efficacy (EE%) were optimized using statistical techniques, i.e., Box-Behnken and Central Composite Design. In contrast to soluble drug formulations, the release rate of medicines from nanoparticles were higher in physiological and acidic pH. Niosomes were more stable at 4 °C, compared to 25 °C. The MTT assay revealed that the IC50 of drug-loaded niosomes was the lowest among all developed formulations. The apoptosis-related genes (CASPASE-3, CASPASE-8, and CASPASE-9) and tumor suppressor genes (BAX, BCL2) were evaluated in cancer cells before and after treatment. In comparison to control cells and cells treated with soluble forms of DXR and PTX, while the expression of BCL2 decreased, the expression of BAX, CASPASE-3, CASPASE-8, and CASPASE-9 was enhanced in cells treated with drug-loaded niosomes. Drug-loaded niosomes inhibited colony formation capacity and increased apoptosis in human AGS gastric cancer cells. Our results indicate that co-delivery of DXR and PTX-loaded niosomes may be an effective and innovative therapeutic approach to gastric cancer.

Radiolabeling of statistically optimized nanosized atorvastatin suspension for liver targeting and extensive imaging of hepatocellular carcinoma

Nanomaterials may be used as efficient, targeted drug-delivery systems for hepatocellular-carcinoma (HCC). These nanocarriers can overcome drug tissue-distribution limitations to achieve maximum liver uptake and tumor accumulation of anticancer drugs. In this study, atorvastatin (ATV) was evaluated in-vitro for its potential effects in HCC. Afterwards, ATV nanosuspension was prepared using modified antisolvent-precipitation ultrasonication technique. A central-composite statistical design was developed to analyze and optimize the effects of the formulation-variables on the physicochemical characteristics of the nanosuspension. The optimized system was re-formulated for further characterization and radio-complexation with technetium-99m(99mTc). Finally, the 99mTc-radiolabeled ATV nanosuspension was evaluated in-vivo for its biological distribution, HCC-targeting ability and radiodiagnostic efficiency. The results indicated an anti-proliferative effect of ATV on HepG-2 cells. Thus, nanosized ATV suspension was then formulated with high physical stability that extended to 6 months. Subsequently, 24h-stable 99mTc-radiolabeled ATV nanosuspension was prepared with 90.3% radiolabeling efficiency. This 99mTc-radiolabeled ATV nanosuspension achieved maximal accumulation in HCC cells (37.6 %ID.g-1) within 15 min after its intravenous administration with minimal distribution to normal liver cells or other body organs. Our findings proposed ATV-nanosuspension as a potential targeted anti-HCC agent and the 99mTc-radiolabeled nanosuspension as a theranostic radiopharmaceutical or sensitive and selective imaging and/or treatment for HCC.

Central Composite Design for the Development of Trimetazidine Dihydrochloride-Loaded Fast Dissolving Film

A fast-dissolving dosage form is an approach used to improve therapeutic efficacy and bioavailability by avoiding the first-pass metabolism of the cargo. Besides, the approach causes rapid cargo absorption from the pre-gastric area which may outcome in the quick inception of action. The trimetazidine dihydrochloride (TDC) is an anti-anginal drug and there is a prerequisite to provide fast onset of action to treat angina. Therefore, the present work was aimed to prepare and evaluate fast-dissolving oral films (FDOF) of TDC to provide fast onset of action. The FDOF is prepared by using the solvent casting method and it was optimized by employing a central composite statistical design. The two independent variables such as HPMC K4M and PEG 400 are the film-forming polymers which are evaluated at three levels. The dependent variables selected as folding endurance, disintegration time, and % drug release. The formulation was prepared and optimized the batch F-4 showed the least disintegration time (19 s) and the highest drug release (98.55±7.90%). Moreover, the ex-vivo mucus permeation study showed better permeation and satisfying physicochemical properties. As per the above results, we conclude that the prepared formulation could be a novel dosage form to improve drug delivery and patient compliance.

Design and Evaluation of Pulsincap System Containing Nanosuspension of Montelukast Sodium for Chronotherapy in Asthma

In the present study, an attempt was made to prepare a pulsincap chronomodulated drug delivery system for the treatment of asthma and associated early morning allergy. Pulsincap capsule was prepared by sealing the drug nanosuspension inside the formaldehyde treated insoluble capsule bodies with a swellable and erodible guar gum plug. The drug, Montelukast sodium (MLS) nanosuspension was prepared by emulsion-solvent evaporation method using HPMC E15 and sodium lauryl sulphate (SLS). Nanosuspension formulations were optimized by using statistical Central composite design (CCD) for the required size and stability. The entire capsules were enteric coated using Cellulose acetate phthalate (CAP). This enteric coat prevents the drug release in the stomach, further the swellable hydrogel plug protect the nanosuspension to maintain the lag phase (5h) and facilitate its burst release in the colon. The length of this lag phase depends upon the concentration and quantity of the hydro gel plug. In order to simulate the GIT environment, the dissolution studies were performed using a sequential pH change method. DSC studies confirmed the absence of drug-excipient interactions. From the design space provided by the CCD, F14 and F15 formulations were considered as optimized. SEM studies were conducted for F14 formulation and this was filled in the Chronomodulated pulsincap systems (CMPs). These CMPs showed the drug release after 5h lag phase. Hence, when CMPs containing MLS nanosuspension is administered during bed time, it starts releasing the drug at the early morning hours to reduce asthma and associated early morning allergies like rhinitis and sneezing. Further, extensive in vivo studies are needed to be conducted to confirm the efficiency of these CMPs.

Micrococcus lylae MW407006 Pigment: Production, Optimization, Nano-Pigment Synthesis, and Biological Activities.

Simple SummaryThe global crisis of increased mortality rates due to the emergence of antimicrobial resistance and cancers has increased researchers’ efforts to find new, potent solutions through implementing natural products in the pharmaceutical industry. The present investigation produced echinenone (yellowish-orange pigment) from Micrococcus lylae MW407006 with potent pharmacological activities. A response surface methodology statistical design was used to optimize the biomass production, pigment concentration, and antimicrobial activity. The Spearman correlation coefficient was assessed, which indicated a strong linear relationship between biomass production, pigment concentration, and antimicrobial activity. Nano-echinenone was physically synthesized through the ball-milling technique. The synthesized nano-echinenone showed higher pharmacological activities (antimicrobial, antioxidant, and antitumor activities) in comparison with the crude pigment. The significantly high selectivity index of the synthesized nano-echinenone proved its safety and paved the way for its possible use in the pharmaceutical industry.Bacterial pigments (e.g., melanin and carotenoids) are considered to be among the most important secondary metabolites due to their various pharmacological activities against cancer and microbial resistance. Different pigmented bacterial strains were isolated from soil samples from El Mahmoudiyah governance and screened for their antimicrobial activity. The most promising pigment producer was identified as Micrococcus lylae MW407006; furthermore, the produced pigment was identified as echinenone (β-carotene pigment). The pigment production was optimized through a central composite statistical design to maximize the biomass production, pigment concentration, and the antimicrobial activity. It was revealed that the most significant fermentation parameters were the glucose (as a carbon source) and asparagine (as a nitrogen source) concentrations. Nano-echinenone was synthesized using the ball milling technique, characterized, and finally assessed for potential antimicrobial, antioxidant, and antitumor activities. The data revealed that the synthesized nano-echinenone had higher antimicrobial activity than the crude pigment. The cytotoxic potency of echinenone and nano-echinenone was investigated in different cell lines (normal and cancer cells). The inhibition of cell proliferation and induction of cell death was observed in Caco-2 and Hep-G2 cells. The data proved that nano-echinenone is a suitable candidate for use as a safe antimicrobial and anti-hepatocellular-carcinoma agent.

Response surface methodology adhering central composite design for the optimization of Zn (II) adsorption using rice husk nanoadsorbent

Present study highlights the effectuality of rice husk nanoadsorbent RHN for the removal of Zn (II) from aqueous solution. A peculiar statistical technique central composite design of response surface methodology by using Design-Expert® software version 11 was executed to investigate Zn (II) removal by varying three adsorption parameters such as pH, dose and metal ion concentration. Quadratic model equation and analysis of variance were outlined in the study. Zn (II) removal was found to be 80% at optimum conditions pH 6, dose 0.8 g/L and metal ion concentration 15 mg/L and desirability was near 0.9. To comprehend the nature of adsorption process, linear forms of isotherms were gratified. Langmuir isotherm model was found to be compatible with adsorption data indicating monolayer adsorption on homogeneous active sites of nanoadsorbent with 0.9978 R2. Pseudo-second order kinetic model fitted well to the adsorption data with R2 0.992. Spontaneous and endothermic nature of the process was depicted by thermodynamic study. Adsorption mechanism is reasonably explained by hydrolysis, precipitation, electrostatic interactions and HASB inreaction. The regeneration of RHN was analysed upto three successive cycles.

Response surface methodological optimization of l-asparaginase production from the medicinal plant endophyte Acinetobacter baumannii ZAS1

BackgroundThis study targets the enhanced production of l-asparaginase, an antitumor enzyme by Acinetobacter baumannii ZAS1. This organism is an endophyte isolated from the medicinal plant Annona muricata. Plackett–Burman design (PBD) and central composite design (CCD) were used for statistical optimization of media components. ResultsThe organism exhibited 18.85 ± 0.2 U/mL enzyme activities in unoptimized media. Eight variables: l-asparagine, peptone, glucose, lactose, yeast extract, NaCl, MgSO4, and Na2HPO4 were screened by PBD. Among them, only four factors—l-asparagine, peptone, glucose, and Na2HPO4—were found to affect enzyme production significantly (p < 0.05). Furthermore, the best possible concentrations and interactive effects of the components that enhance this enzyme’s output were chosen by using CCD on these selected variables. The results revealed that an optimized medium produces a higher concentration of enzymes than the unoptimized medium. After optimizing media components, the maximum l-asparaginase activity was 45.59 ± 0.36 U/mL, around the anticipated value of 45.04 ± 0.42 U/mL. After optimization of process parameters, it showed a 2.41-fold increase in the production of l-asparaginase by the endophyte Acinetobacter baumannii ZAS1. ConclusionThe findings of this study indicated that an endophyte, Acinetobacter baumannii ZAS1 that produces l-asparaginase could be used to increase enzyme output. However, using the statistical methods Plackett-Burman design and central composite design of response surface methodology is a handy tool for optimizing media components for increased l-asparaginase synthesis.

Agroindustrial co-products and waste cooking oil in the production of lipases by thermophilic Bacillus licheniformis SMIA-3

The present study investigated the potential lipase production for Bacillus licheniformis SMIA-3 using the agro-industrial co-products: orange flour (OF) and grape flour (GF) blend waste cooking oil (WCO). The OF was selected due to its best source for lipase production observed in preliminary tests. Therefore, OF was tested at different fermentation times at 50°C using the statistical design Central Composite Rotatable Design (CCRD) allied to the response surface. An optimal region was found with lipolytic activity of 0.349 U mL-1 with OF and WCO filters around (0.50% w v-1) and between (0.55 and 0.75% w v-1), respectively, and the fermentation time at the central point (42h). Data supplied a method to produce lipase using orange flour and frying oil, as a way to reuse these waste as feedstock to obtain employable lipase and lower production costs with biotechnological applications in industrial sector

Invertase production by yeast mediated silver nanoparticles using statistical tool central composite design

Nanotechnology is a promising field which modifies the properties of materials at the atomic level to attain specific properties with nanometer sized items. The enzyme used in the present study is invertase (beta – fructofuranosidase fructohydrolase, EC 3.2.1.26), which hydrolysis sucrose to fructose and glucose. In industry, the invertase enzyme is used for the significant production of fructose syrup from sucrose syrup. Silver nanoparticles were synthesized from baker’s yeast by bioreduction method. Invertase enzyme was extracted using these yeast mediated AgNPs from a low cost substrate (bagasse). This study focuses on optimization activity interaction of AgNPs induced enzyme invertase, including three factors: pH, temperature (°C), substrate concentration (gl−1). All experiments are designed according to response surface method (RSM) – Central Composite Design (CCD). As the result pH was identified as significant factor (p < 0.05). A maximum activity of 0.266 IUml−1 was achieved at optimum values of substrate concentration (10.29 gl−1), pH (6.3) and temperature (29.06 °C). Technically, these silver nanoparticles are immensely applied to biomedical field. Not only its application, the production process is cost-effective, compatible for medical and pharmaceutical applications as well as large scale commercial production.

Adsorption of bisphenol A from aqueous solution onto organoclay: Experimental design, kinetic, equilibrium and thermodynamic study

Bisphenol-A (BPA) is a common plasticizer that has been considered a chemical of concern due to its endocrine disruption potential. In this sense, this paper aimed to investigate the adsorption of this contaminant onto commercial organophilic clay named Spectrogel® as means of water remediation. For this, characterization techniques were carried out before and post-process to identify any major alterations to the adsorbent due to BPA uptake. A statistical central composite rotational design (CCRD) technique was performed for process optimization. The impact of adsorbent dosage mass (0.128–1.472 g.100 mL−1, solution concentration (0.064–0.736 mmol/L−1) and particle diameter (0.28–1.0 μm) on the adsorption capacity was analysed. It was defined 0.064 g of adsorbent dosage and an average particle size of 0.855 μm as optimum conditions, in which a 0.193 mmol.g−1 (44.060 mg.g−1) adsorption capacity was obtained. Static adsorption assays showed that the kinetics better followed the external mass transfer resistance model, whilst the isotherm data obtained at 15 and 25 °C were well expressed by the Freundlich model and at 40 and 55 °C by the D-R model, achieving a maximum adsorptive capacity of 0.4 mmol.g−1 (91.316 mg.g−1). The thermodynamic parameters reflected a spontaneous and endothermic process. Furthermore, numerous eluent solutions were tested to assess the regenerability of the adsorbent and sodium hydroxide displayed the best desorption capacity (77.8%). The Spectrogel® clay has shown to be very promising as an alternative adsorbent in the remediation of water contaminated with BPA.

How centrifugation influences the recovery and soy peptone incorporation in hyaluronic acid coils from fermentation

Hyaluronic acid from fermentation (bio-HA) is a high-added-value biopolymer with a wide range of applications in aesthetic and medical areas. Bio-HA is a capsular exopolysaccharide highly hydrophilic with a coiled structure and high negative charge density at physiological pH. Centrifugation, currently used to separate microbial cells after fermentation, should significantly affect the bio-HA interactions with the medium components. Although the literature shows various centrifugation conditions for bio-HA, there is no concern about its recovery and characterization. We examined how centrifugation influences its recovery and characterized interactions with soy peptone (SP), used as a nitrogen source. We collected experimental data according to a statistical central composite design (CCD) planning with replicates at the central point with time (8–22 min) and spin (582xg to 12,402xg) as independent variables. The obtained results show bio-HA recoveries ranged from 45 ± 0.5–100% as dosed in the supernatant. The incorporation of amino acids and peptides from SP increased HA coils' density, causing losses due to sedimentation at higher spins and times. Furthermore, SP incorporation also changed the coils' size regarding HA standards of molar mass 106,105 and 104 Da. We conclude centrifugation should significantly impact downstream processing and the total cost of bio-HA production.