Lipases are enzymes that have the potential to hydrolyze triacylglycerol to free fatty acids and glycerol and have various applications. The aim of the present study was to isolate and screen marine ...bacteria for lipase production, optimize the production, and treat wastewater. A total of 20 marine bacterial isolates were obtained from the Mediterranean Sea and were screened for lipase production. All isolates were found to have lipolytic ability. The differences between the isolates were studied using RAPD-PCR. The most promising lipase producer (isolate 3) that exhibited the highest lipolytic hydrolysis (20 mm) was identified as
HSS using 16S rDNA analysis and had the accession number MF581790. Optimization of lipase production was carried out using the Plackett-Burman experimental design with cotton seed oil as the inducer under shaking conditions at 10°C. The most significant factors that affected lipase production were FeSO
, KCl, and oil concentrations. By using the optimized culture conditions, the lipase activity increased by 1.8-fold compared with basal conditions. Immobilization by adsorption of cells on sponge and recycling raised lipase activity by 2.8-fold compared with free cells. The repeated reuse of the immobilized
HSS maintained reasonable lipase activity. A trial for the economic treatment of oily wastewater was carried out. Removal efficiencies of biological oxygen demand, total suspended solids, and oil and grease were 87.63, 90, and 94.7%, respectively, which is promising for future applications.
•Degradation of phenol using Chlorella pyrenoidosa demonstrated.•Chlorella pyrenoidosa proved to be an efficient phenol degrading microalga.•The experimentation performed under ambient ...condition.•4g/L of Chlorella pyrenoidosa degraded 97% of 0.8g/L-phenol within 4days.•3 significant factors identified- concentration of algae, phenol and reaction time.
Statistical optimization designs were used to optimize the phenol degradation using Chlorella pyrenoidosa. The important factor influencing phenol degradation was identified by two-level Plackett–Burman Design (PBD) with five factors. PBD determined the following three factors as significant for phenol degradation viz. algal concentration, phenol concentration and reaction time. CCD and RSM were applied to optimize the significant factors identified from PBD. The results obtained from CCD indicated that the interaction between the concentration of algae and phenol, phenol concentration and reaction time and algal concentration and reaction time affect the phenol degradation (response) significantly. The predicted results showed that maximum phenol degradation of 97% could be achieved with algal concentration of 4g/L, phenol concentration of 0.8g/L and reaction time of 4days. The predicted values were in agreement with experimental values with coefficient of determination (R2) of 0.9973. The model was validated by subsequent experimentations at the optimized conditions.
► Design of experiments can efficiently optimise a chromatographic response by finding best values of factors. ► DoE with a Plackett–Burman design can be used in method validation to show robustness ...of a method. ► Central composite designs (CCD) are the most used for optimisation of 2–5 factors. ► Box–Behnken and Doehlert designs can be more efficient than CCD. ► D-optimal designs are used when the factor space is restricted or numbers of possible experiments is limited.
The ability of a chromatographic method to successful separate, identify and quantitate species is determined by many factors, many of which are in the control of the experimenter. When attempting to discover the important factors and then optimise a response by tuning these factors, experimental design (design of experiments, DoE) gives a powerful suite of statistical methodology. Advantages include modelling by empirical functions, not requiring detailed knowledge of the underlying physico-chemical properties of the system, a defined number of experiments to be performed, and available software to accomplish the task. Two uses of DoE in chromatography are for showing lack of significant effects in robustness studies for method validation, and for identifying significant factors and then optimising a response with respect to them in method development. Plackett–Burman designs are widely used in validation studies, and fractional factorial designs and their extensions such as central composite designs are the most popular optimisers. Box–Behnken and Doehlert designs are becoming more used as efficient alternatives. If it is not possible to practically realise values of the factors required by experimental designs, or if there is a constraint on the total number of experiments that can be done, then D-optimal designs can be very powerful. Examples of the use of DoE in chromatography are reviewed. Recommendations are given on how to report DoE studies in the literature.
•Evidence that UAE is effective for extraction of anthocyanins from haskap berries.•Significant variables can be screened by Plackett–Burman design.•The extraction of anthocyanins was optimized by ...RSM using Box–Behnken design.•Proximity of predicted and practical responses indicate the adequacy of the model.
Haskap berries (Lonicera caerulea L.) are a rich source of bioactive molecules. As such, the extraction of anthocyanins is important for the development of many value-added products and functional food ingredients. In this paper, the ultrasound-assisted extraction (UAE) of anthocyanins from haskap berries was investigated. Significant independent variables were screened and optimized using Plackett–Burman (PB) and Box–Behnken (BB) designs, respectively. The mathematical model showed a high coefficient of determination (R2=0.9396) and the optimum conditions for the extraction were as follows: liquid/solid ratio 25:1 (mL/g), solvent composition of 80% ethanol, addition of 0.5% formic acid, ultrasound bath temperature of 35°C for 20min. Under these conditions, the total anthocyanin content of 22.73mg cyaniding 3-glucoside equivalents (C3G)/g dry weight (DW) was consistent with the predicted response of 22.45mg C3G/g DW from the model (mean error of 1.28%). Five anthocyanins were identified in the optimized extract, namely cyanidin 3,5-diglucoside, cyanidin 3-glucoside, cyanidin 3-rutinoside, pelargonidin 3-glucoside, and peonidin 3-glucoside. Thus, UAE is a suitable technique for the extraction of anthocyanins from haskap berries.
Scleroglucan is a notable member of the β-glucan microbial polysaccharides with a long tradition of industrial and therapeutic use. The local strain, previously identified as Athelia rolfsii TEMG MH ...236106 produced an appreciable amount of scleroglucan using glucose as a carbon source and yeast extract as a nitrogen source. Plackett-Burman design was employed to effectively screen critical medium composition, culture, and fermentation conditions. Athelia rolfsii TEMG MH 236106 produced the maximum amount of scleroglucan (18.12 g/L) with a 45.3 % glucose conversion. Out of the eleven variables, the most effective factors showing a high level of significance are as follows: glucose, yeast extract, citric acid, inoculum disc numbers, culture volume and incubation time. An update to maximize scleroglucan production in the central composite design for four parameters (glucose and yeast extract concentrations, disc number, medium volume and incubation time) with 31 runs was applied and the production of scleroglucan reached its maximum at 31.56 g/L with 78.9 % glucose conversion. Three models of Sclg-5-fluorouracil complexes have been employed to study in vitro drug release investigations. Hence, the Sclg-5-FU (5 and 10 mg/mL) models appeared to be the most suitable for drug administration due to their concentration and distribution within capsules.
Graphical abstract Display omitted
•Synthesis and characterization of IL modified β-cyclodextrin/attapulgite were presented.•Study of optimum experimental conditions for extraction procedures.•Rapid and efficient extraction without ...much organic solvents.•The proposed method was applicable for real tea drink and honey samples.
A green, simple, inexpensive dispersive solid-phase microextraction method coupled with high-performance liquid chromatography was developed for rapid screening and selective recognition of benzoylurea insecticides (BUs) in honey and tea beverages. A novel adsorbent, ionic liquid (IL)-modified β-cyclodextrin/attapulgite (β-CD/ATP), was prepared by immobilizing IL on the surface of β-CD/ATP. A series of demanding extraction conditions were investigated through the experimental design. Under optimum conditions, the limits of detection for the analytes varied from 0.12 to 0.21μgL−1. The enrichment factors ranged from 112 to 150 folds. Linearities in the range of 5–500ngmL−1 were achieved for four BUs, while the correlation coefficients ranged from 0.9997 to 1.0000 and the recoveries from 84.5% to 104.7%. The precision of this method for the four BUs corresponded to intra-day and inter-day RSDs% lower than 3.85%. Finally, the proposed technique was applied for the preconcentration of the BUs from real samples with satisfactory results.
•Estimating the effect of variables on arsenic species extraction by experimental designs.•Extraction of arsenic species in rice samples efficiently and simply using water as the extractant.•The ...proposed method provided good extraction efficiency and species stability.
Statistical experimental designs were employed to optimize the extraction condition of arsenic species (As(III), As(V), monomethylarsonic acid (MMA) and dimethylarsonic acid (DMA)) in paddy rice by a simple solvent extraction using water as an extraction reagent. The effect of variables were estimated by a two-level Plackett–Burman factorial design. A five-level central composite design was subsequently employed to optimize the significant factors. The desirability parameters of the significant factors were confirmed to 60min of shaking time and 85°C of extraction temperature by compromising the experimental period and extraction efficiency. The analytical performances, such as linearity, method detection limits, relative standard deviation and recovery were examined, and these data exhibited broad linear range, high sensitivity and good precision. The proposed method was applied for real rice samples. The species of As(III), As(V) and DMA were detected in all the rice samples mostly in the order As(III)>As(V)>DMA.
The accuracy of the particle parameter settings directly affects the reliability of the simulation results. The discrete element method used a repose angle test to address incorrect particle ...parameter settings when throwing straw particles thrown by a chaff cutter. The tests calibrated the static and rolling friction coefficients using the repose angle of a mixture of maize stalk internodal tissue, pith, and nodal tissue particles as response indicators. Physical tests measured particle materiality parameters and contact parameters to provide data for the simulation tests. A Plackett-Burman design was performed to test the significance of the parameters to be calibrated. The results show that the static friction coefficient of Rind-Node, the rolling friction coefficient of Rind-Rind, the rolling friction coefficient of Pith-Pith, and the rolling friction coefficient of Pith-Iron have a significant effect on the repose angle. The purpose of the steepest ascent test is to narrow down the optimization range of the parameters. The central composite design was used to determine the DEM parameters' levels and quantify their effects. The central composite design test modeled a second-order polynomial regression equation for the repose angle and significance parameters. The physical test values were used as the target values for the optimization solution to obtain a calibrated and better combination of simulation parameters. The two-sample heteroskedasticity t-test showed no significant difference between the simulated and experimental values. The maximum relative error was 1.75%, the mean relative error was only 0.29%, verifying the reliability and authenticity of the simulation test. These parameters provide a basis for future work, such as the design of a corn stalk processing machine and the discrete-element study on the motion of corn stalk particles inside such machines.
Display omitted
Ammonia recovery from wastewater has positive environmental benefits, avoiding eutrophication and reducing production energy consumption, which is one of the most effective ways to manage nutrients ...in wastewater. Specifically, ammonia recovery by membrane distillation has been gradually adopted due to its excellent separation properties for volatile substances. However, the global optimization of direct contact membrane distillation (DCMD) operating parameters to maximize ammonia recovery efficiency (ARE) has not been attempted. In this work, three key operating factors affecting ammonia recovery, i.e., feed ammonia concentration, feed pH, and DCMD running time, were identified from eight factors, by a two-level Plackett-Burman Design (PBD). Subsequently, Box-Behnken design (BBD) under the response surface methodology (RSM) was used to model and optimize the significant operating parameters affecting the recovery of ammonia though DCMD identified by PBD and statistically verified by analysis of variance (ANOVA). Results showed that the model had a high coefficient of determination value (R2 = 0.99), and the interaction between NH4Cl concentration and feed pH had a significant effect on ARE. The optimal operating parameters of DCMD as follows: NH4Cl concentration of 0.46 g/L, feed pH of 10.6, DCMD running time of 11.3 h, and the maximum value of ARE was 98.46%. Under the optimized conditions, ARE reached up to 98.72%, which matched the predicted value and verified the validity and reliability of the model for the optimization of ammonia recovery by DCMD process.
Display omitted
•PBD was used to screen the important factors affecting ammonia recovery.•NH4Cl concentration, feed pH, and DCMD running time were identified as significant factors.•RSM was employed to optimize the operating parameters of DCMD.•Ammonia recovery efficiency was high to 98.72% under optimized conditions.•High feed pH promoted ammonia mass transfer but increased ammonia loss.
PDF
