Response surface methodology (RSM) in evaluation of the vitamin C concentrations in microwave treated milk

Harnessing the power of Neobacillus niacini AUMC-B524 for silver oxide nanoparticle synthesis: optimization, characterization, and bioactivity exploration

BACKGROUND

Biotechnology provides a cost-effective way to produce nanomaterials such as silver oxide nanoparticles (Ag2ONPs), which have emerged as versatile entities with diverse applications. This study investigated the ability of endophytic bacteria to biosynthesize Ag2ONPs.

RESULTS

A novel endophytic bacterial strain, Neobacillus niacini AUMC-B524, was isolated from Lycium shawii Roem. & Schult leaves and used to synthesize Ag2ONPS extracellularly. Plackett-Burman design and response surface approach was carried out to optimize the biosynthesis of Ag2ONPs (Bio-Ag2ONPs). Comprehensive characterization techniques, including UV-vis spectral analysis, Fourier transform infrared spectroscopy, transmission electron microscopy, X-ray diffraction, dynamic light scattering analysis, Raman microscopy, and energy dispersive X-ray analysis, confirmed the precise composition of the Ag2ONPS. Bio-Ag2ONPs were effective against multidrug-resistant wound pathogens, with minimum inhibitory concentrations (1-25 µg mL-1). Notably, Bio-Ag2ONPs demonstrated no cytotoxic effects on human skin fibroblasts (HSF) in vitro, while effectively suppressing the proliferation of human epidermoid skin carcinoma (A-431) cells, inducing apoptosis and modulating the key apoptotic genes including Bcl-2 associated X protein (Bax), B-cell lymphoma 2 (Bcl-2), Caspase-3 (Cas-3), and guardian of the genome (P53).

CONCLUSIONS

These findings highlight the therapeutic potential of Bio-Ag2ONPs synthesized by endophytic N. niacini AUMC-B524, underscoring their antibacterial efficacy, anticancer activity, and biocompatibility, paving the way for novel therapeutic strategies.

Bioproduction and optimization of newly characterized melanin pigment from Streptomyces djakartensis NSS-3 with its anticancer, antimicrobial, and radioprotective properties

BACKGROUND

Melanin is a natural pigment that is considered a promising biomaterial for numerous biotechnological applications across several industries. Melanin has biomedical applications as antimicrobial, anticancer, and antioxidant properties. Additionally, in the pharmaceutical and cosmetic industries, it is used in drug delivery and as a radioprotective agent. Also, melanin has environmental uses in the fields of bioremediation and the food industry. The biosynthesis of melanin pigment is an area of interest for researchers due to its multifunctionality, high compatibility, and biodegradability. Therefore, our present work is the first attempt to characterize and optimize the productivity of melanin pigment from Streptomyces djakartensis NSS-3 concerning its radioprotection and biological properties.

RESULTS

Forty isolates of soil actinobacteria were isolated from the Wadi Allaqui Biosphere Reserve, Egypt. Only one isolate, ACT3, produced a dark brown melanin pigment extracellularly. This isolate was identified according to phenotypic properties and molecular phylogenetic analysis as Streptomyces djakartensis NSS-3 with accession number OP912881. Plackett-Burman experimental design (PBD) and response surface methodology (RSM) using a Box-Behnken design (BBD) were performed for optimum medium and culturing conditions for maximum pigment production, resulting in a 4.19-fold improvement in melanin production (118.73 mg/10 mL). The extracted melanin pigment was purified and characterized as belonging to nitrogen-free pyomelanin based on ultraviolet-visible spectrophotometry (UV-VIS), Fourier transform infrared (FT-IR), Raman spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and NMR studies. Purified melanin demonstrated potent scavenging activity with IC50 values of 18.03 µg/mL and revealed high potency as sunscreens (in vitro SPF = 18.5). Moreover, it showed a nontoxic effect on a normal cell line (WI38), while it had a concentration-dependent anticancer effect on HCT116, HEPG, and MCF7 cell lines with IC50 = 108.9, 43.83, and 81.99 µg/mL, respectively. Also, purified melanin had a detrimental effect on the tested MDR bacterial strains, of which PA-09 and SA-04 were clearly more susceptible to melanin compared with other strains with MICs of 6.25 and 25 µg/mL, respectively.

CONCLUSION

Our results demonstrated that the newly characterized pyomelanin from Streptomyces djakartensis NSS-3 has valuable biological properties due to its potential photoprotective, antioxidant, anticancer, antimicrobial, and lack of cytotoxic activities, which open up new prospects for using this natural melanin pigment in various biotechnological applications and avoiding chemical-based drugs.

Optimization of stabilized anaerobic landfill leachate treatment using ozonation with metallic compound using response surface methodology

Malaysia encounters a consistent rise in the generation of solid waste and leachate on a daily basis. It should also be noted that leachate has a low degree of biodegradability (BOD5 /chemical oxygen demand [COD]), as shown by its BOD5 /COD ratio. Its high toxicity levels significantly threaten the environment, water bodies, and human well-being. High concentrations of COD, color, and ammoniacal nitrogen (NH3 -N) in leachate prevent this wastewater from being allowed to be discharged directly into the water body. Therefore, an effective process to remove the pollutant is desired. The aims of this study are to investigate the performance of ozonation with two metallic compounds, ZrCl4 and SnCl4 , and optimize their performance using response surface methodology (RSM). In this study, the performance of ozonation with ZrCl4 (O3 /ZrCl4 ) recorded better pollutant removals compared with the ozonation with tin tetrachloride (O3 /SnCl4 ), as seen in the removals of 99.8%, 93.5%, and 46.3% for color, COD, and NH3 -N, respectively. These removals were achieved by following the experimental model (optimum experiment condition) generated by RSM at O3 dosage of 31 g/m3 , COD and ZrCl4 dosage ratio (COD, mg/L/ZrCl4 , mg/L) of 1:1.35, with the pH solution of 8.78 and reaction time of 89 min. The R2 of each parameter for this model was recorded as 0.999 (COD), 0.999 (color), and 0.998 (NH3 -N), respectively. These data indicated that the model is well fitted as the predicted data by statistical calculation and in good agreement with the actual data. PRACTITIONER POINTS: The performance of O3 /ZrCl4 and O3 /SnCl4 was examined for remediate stabilized landfill leachate. The performance of O3 /ZrCl4 and O3 /SnCl4 was optimized using RSM, and a set of experimental models was generated and tested. O3 /ZrCl4 recorded the higher removal of COD, color, and NH3 -N compared with O3 /SnCl4 . At best condition, both methods recorded removal as 89% to 99.8% of pollutants in leachate and product clear effluent. This finding gives a new approach to treat landfill leachate effectively and efficiently.

Fundamental alteration of cellular biochemicals from attached microalgae onto palm kernel expeller waste upon optimizing the growth environment in forming adhesion complex

Changing the growth environment for microalgae can overall lead to the fundamental alteration in cellular biochemicals whilst attaching onto palm kernel expeller (PKE) waste to form adhesion complex in easing harvesting at stationary growth phase. This study had initially optimized the PKE dosage, light intensity and photoperiod in maximizing the attached microalgal productivity being attained at 0.72 g/g day. Lipid content increased progressively from pH 3 to pH 11, with the highest value observed at pH 11. Meanwhile, in terms of protein and carbohydrate contents, the highest values were obtained by cultivation medium of pH 5 with 9.92 g and 17.72 g, respectively followed by pH 7 with 9.16 g and 16.36 g, respectively. Moreover, the findings also suggested that the low pH mediums utilized polar interactions in the formation of complexes between PKE and microalgae, whereas at higher pH levels, the non-polar interactions became more significant. The work of attachment was thermodynamically favourable towards the attachment formation with values greater than zero which was also aligned with the microscopic surface topography, i.e., revealing a clustering pattern of microalgae colonizing the PKE surface. These findings contribute to comprehensive understanding of optimizing growth condition and harvesting strategy of attached microalgae in attaining the cellular biochemical components, facilitating the development of efficient and sustainable bioresource utilization.

Optimisation of process parameters using response surface methodology to improve the liquid fraction yield from pyrolysis of water hyacinth

The water hyacinth has been identified as a persistent threat to the pillars of sustainability, resulting in an increased demand for cost-effective mitigation measures. Existing control measures such as chemical and mechanical methods have proved ineffective and expensive, although their use in a biorefinery is deemed sustainable. The study focused on using the response surface methodology of Design-Expert to optimise process parameters, emphasising temperature and particle size, to improve the liquid fraction yield from the pyrolysis of water hyacinths. The experiment was conducted in the temperature range of 273.22 and 676.78 °C, with a particle size range of 380 and 2620 µm, and subjected to a heating rate of 30 °C/min and a nitrogen flow rate of 25 l/min. The results suggest that an increase in temperature and particle size led to a rise in the liquid fraction and a decrease in char. The liquid fraction increased from 24.36 wt.% at 273.22 °C to 48.45 wt.% at 575 °C and reduced to 25.56 wt.% at 626.78 °C. Char decreased from 58.21 to 33.84 wt.% at 626.78 °C. Given this, the quadratic model was found fit for optimisation. Statistical analysis of variance showed good agreement between actual data and the predicted model. This study argues that the valorisation of water hyacinths, if accompanied by policies and strategies, can trigger comprehensive socio-economic and environmental benefits by implementing optimum conditions to generate an improved liquid fraction that tends to influence its commercialisation. It is envisaged that the study's findings will inform policy discussions and formulation.

Optimization of magnetic nano-iron production by Aspergillus flavipes MN956655.1 using response surface methodology and evaluation of their dye decolorizing and antifungal activities

Iron nanoparticles have been biosynthesized by a new Aspergillus flavipes isolate. Size of biosynthesized iron nanoparticles was in a range of 32.7 and 47.6 nm, their surface charge was - 33.5 ± 5.3 and they showed semihard ferromagnetic behavior. Salt concentration, volume of added culture filtrate and pH have been optimized using response surface methodology. A significant effect for the added culture filtrate and a mutual interaction between this factor and the pH has been detected. Model validation results showed 3.3% deviation from the statistically predicted values which reflects the accuracy of the employed model. Optimization process has increased the quantity of iron in the prepared samples and the amount of produced iron nanoparticles to a fourfold. The optimized conditions have stimulated the formation of nanoparticles in a tetrahedron shape rather than the truncated tetrahedron shape without affecting their size or surface charge. The biosynthesized iron nanoparticles have recorded a good decolorization activity for methylene blue. They showed 57 ± 4.3 decolorization percent after 6 h when tested with only 0.1 mg/ml concentration. Moreover, 50 ppm concentration has exerted a detectable antifungal activity against Alternaria solani. This study represents a new competitive green synthesis method for magnetic iron nanoparticle.

Residual palm kernel expeller as the support material and alimentation provider in enhancing attached microalgal growth for quality biodiesel production

Albeit the biodiesel production from suspended microalgal system has gained immense interests in recent years, the domineering limitation of being economically infeasible has hindered this technology from partaking into a large-scale operation. To curtail this issue, attached growth system had been introduced by various studies; however, those were still unable to alleviate the socio-economic challenges faced in commercializing the microalgal biomass production. Thus, this study had developed a novel approach in cultivating-cum-harvesting attached Chlorella vulgaris sp. microalgae, whilst using solid organic waste of palm kernel expeller (PKE) as the supporting and alimentation material for microalgal biofilm formation. The effects of three variables, namely, PKE dosage, light intensity, and photoperiod, were initially modelled and later optimized using Response Surface Methodology tool. The derived statistical models could predict the growth performances of attached microalgal biomass and lipid productivity. The optimum growing condition was attained at PKE dosage of 5.67 g/L, light intensity of 197 μmol/m² s and photoperiod of 8 light and 16 dark hours/cycle, achieving the microalgal density and lipid content of 9.87 ± 0.05 g/g and 3.39 ± 0.28 g/g, respectively, with lipid productivity of 29.6 mg/L day. This optimum condition had led to the intensification of biodiesel quality with a high percentage of monounsaturated fatty acid, i.e., oleic acid (C18:1), encompassing 81.86% of total fatty acid methyl ester components. Given that the positive acquisition of PKE as an excellent supporting material in enhancing the microalgal density and lipid productivity that had resulted in the commercially viable biodiesel quality, this study served as a novel revolution in augmenting the microalgae and solid waste utilities for sustainable energy generation.

Modeling and Optimization of a Compression Ignition Engine Fueled with Biodiesel Blends for Performance Improvement

Biodiesel is considered to be a promising alternative option to diesel fuel. The main contribution of the current work is to improve compression ignition engine performance, fueled by several biodiesel blends. Three metrics were used to evaluate the output performance of the compression ignition engine, as follows: brake torque (BT), brake specific fuel consumption (BSFC), and brake thermal efficiency (BTE), by varying two input parameters (engine speed and fuel type). The engine speeds were in the 1200–2400 rpm range. Three biodiesel blends, containing 20 vol.% of vegetable oil and 80 vol.% of pure diesel fuel, were prepared and tested. In all the experiments, pure diesel fuel was employed as a reference for all biodiesel blends. The experimental results revealed the following findings: although all types of biodiesel blends have low calorific value and slightly high viscosity, as compared to pure diesel fuel, there was an improvement in both BT and brake power (BP) outputs. An increase in BSFC by 7.4%, 4.9%, and 2.5% was obtained for palm, sunflower, and corn biodiesel blends, respectively, as compared to that of pure diesel. The BTE of the palm oil biodiesel blend was the lowest among other biodiesel blends. The suggested work strategy includes two stages (modeling and parameter optimization). In the first stage, a robust fuzzy model is created, depending on the experimental results, to simulate the output performance of the compression ignition engine. The particle swarm optimization (PSO) algorithm is used in the second stage to determine the optimal operating parameters. To confirm the distinction of the proposed strategy, the obtained outcomes were compared to those attained by response surface methodology (RSM). The coefficient of determination (R2) and the root-mean-square-error (RMSE) were used as comparison metrics. The average R2 was increased by 27.7% and 29.3% for training and testing, respectively, based on the fuzzy model. Using the proposed strategy in this work (integration between fuzzy logic and PSO) may increase the overall performance of the compression ignition engine by 2.065% and 8.256%, as concluded from the experimental tests and RSM.

Microwave applications in the food industry: an overview of recent developments

Microwave radiation has the ability to heat a material with dielectric properties. Material absorbs microwave energy and then converts it into heat, which gives the possibility of a wide use of microwaves in many industry sectors or agricultural sciences. Microwaves are especially widely used in food industry. The main objective of this paper is to present an overview of recent development regarding microwave applications in food industry. Many techniques in food processing (pasteurization, sterilization, drying, thawing, blanching and stunning) are assisted by microwave energy. It should be mentioned also the use of microwaves in nutrients and nutraceuticals production. Waste generation is an integral part of food production. Microwaves have also application in wastes management. The results of experiments, factors affecting heating and their practical application have been discussed. Many cases have been compared with conventional process methods. The use of microwaves shows many advantages. The most important aspect is shortening the time of the thermal process (even by 50%) and reducing the costs of the operation. In addition, it allows to increase the efficiency of processes while maintaining high quality. The examples of microwave applications given in the article are environmentally- friendly because the conditions of thermal processing allow for reducing the use of solvents and the amount of sewage by decreasing the demand for water. It is anticipated that microwaves will become increasingly popular, with the development of new microwave technologies solving many problems in the future.

Comparative profiling of lactic acid bacteria isolates in optimized and spontaneous fermentation of cowpea leaves

In as much as spontaneous fermentation of cowpea leaves enhances product diversification, the process is rather slow with poor product quality. Limited work has been undertaken to provide input toward standardization of the process and enhancing of product quality. The current study sought to evaluate the in-process fermentative bacteria profile changes due to the effect of optimization of fermentation process of cowpea leaves. Lactic acid bacteria (LAB) isolates from spontaneous and optimized fermentation were characterized using biochemical tests, whereby optimization was done using the Response Surface Methodology model of the central composite design in the Design Expert Software. The RSM models accounted for 89% and 60% variability in the response variables of pH and titratable acidity, respectively (p < .001). Increasing the sugar concentration and period of fermentation significantly (p < .05) increased the titratable acidity, while reducing the pH. The optimal fermentation parameters were established as sugar and salt concentrations of 5% and 2%, respectively, 16 days of fermentation, pH of 3.8 and titratable acidity of 1.22% with a desirability of 0.859. Of the 13 identified LAB isolates, Lactobacillus brevis and Lactococcus lactis dominated the onset stage of spontaneous fermentation whereas only Lactobacillus brevis dominated the onset stage of optimized fermentation. Additionally, the final stage with the dominant isolates of L. plantarum was longer in the spontaneous fermentation process than in the optimized process. Evidently, optimizing the fermentation process resulted in increasing dominance by heterofermenters in the production of soured cowpea leaves, with the yielded product having enhanced acidity.

Ultra-High-Performance Liquid Chromatography-Electrospray Ionization-Mass Spectrometry for High-Neuroanatomical Resolution Quantification of Brain Estradiol Concentrations

Ventromedial hypothalamic nucleus (VMN) control of glucostasis is estradiol (E-2)-dependent. E-2 regulation of VMN reactivity to hypoglycemia may involve changes in signal volume due to altered aromatase expression. Here, high-resolution micropunch dissection tools for isolation of segmental VMN tissue were used with Design of Experiments-refined uHPLC-electrospray ionization-mass spectrometry (LC-ESI-MS) methodology to investigate the premise that effects of acute and/or recurring hypoglycemia on VMN E-2 content are sex-dimorphic. Relationships among multiple independent mass spectrometric operational variables were assessed by Central Composite Design (CCD) to amplify E-2 chromatogram area. Combinations of spectrometric temperature and gas pressure variable combinations were screened by Akaike Information Criterion correction modeling. A Fibonacci Sequence design using CCD minimum and maximal variable limits produced a small-run model that replicated maximal response from CCD. E-2 chromatographic response was further enhanced by optimization of solid phase extraction and instrument source and collision-induced dissociation voltages. In male rats, acute and chronic hypoglycemia respectively elevated or diminished E-2 concentrations relative to baseline in both rostral and caudal VMN. However, females exhibited regional variability in tissue E-2 profiles during acute (increased, rostral VMN; no change, caudal VMN) and recurring (no change, rostral VMN; increased, caudal VMN) hypoglycemia. Outcomes demonstrate requisite LC-ESI-MS sensitivity for E-2 quantification in small-volume brain tissue samples acquired with high-neuroanatomical specificity. Current methodology will facilitate efforts to investigate physiological consequences of VMN rostro-caudal segment-specific acclimation of E-2 profiles to recurring hypoglycemia, including effects on gluco-regulatory function, in each sex.

Bioluminescent method for the rapid screening of toxic heayy metals in environmental samples using Photobacterium leiognathi strain AK-MIE

Assessment of eco-toxicant using bioluminescent bacterial assay is a widely used and globally accepted method. In this work, a new luminescent bacterium was isolated from squid (Loligo duvauceli) and identified as Photobacterium leiognathi strain AK-MIE using 16S rRNA, phylogeny analysis. The predicted optimum conditions by RSM were 2.76% (w/v) NaCl, 2.28% (w/v) peptone, 0.34% (w/v) yeast extract, and pH 6.83 with 541,211.80 RLU of luminescent production whereas the predicted optimum conditions by ANN were 2.21% (w/v) NaCl, 2.27% (w/v) peptone, 0.39% (w/v) yeast extract, and pH 6.94 which produced 541,986.20 RLU. The validation analysis of both RSM and ANN show 0.60% and 0.69% deviation from the predicted results indicating that both models provided good quality predictions with ANN showing a superior data fitting capability for non-linear regression analysis. Toxicity tests show strain AK-MIE was sensitive to mercury (concentration causing 50% inhibition or IC₅₀ of 0.00978 mgL^-1), followed by cadmium (IC₅₀ of 0.5288 mgL^-1), copper IC₅₀ of (0.8117 mgL^-1), silver (IC₅₀ of 1.109 mgL^-1), and lead (IC₅₀ of 10.71 mgL^-1) which are more sensitive than previously isolated luminescent bacteria, suggesting that strain AK-MIE has the potential to be used in toxicity assessment of heavy metals in the environment. Based on the field trial results, several sediment samples from industrial areas in Bangi, Selangor managed to inhibit the bioluminescence of strain AK-MIE. Validation method carried out using ICP-MS proved the presence of several toxic heavy metal elements.

Optimization of Ultra-High-Performance Liquid Chromatography-Electrospray Ionization-Mass Spectrometry Detection of Glutamine-FMOC Ad-Hoc Derivative by Central Composite Design

Glutamine (Gln) is converted to excitatory (glutamate, aspartate) and inhibitory (γ-amino butyric acid) amino acid neurotransmitters in brain, and is a source of energy during glucose deprivation. Current research utilized an Analytical Quality by Design approach to optimize levels and combinations of critical gas pressure (sheath, auxiliary, sweep) and temperature (ion transfer tube, vaporizer) parameters for high-sensitivity mass spectrometric quantification of brain tissue glutamine. A Design of Experiments (DOE) matrix for evaluation of relationships between these multiple independent variables and a singular response variable, e.g. glutamine chromatogram area, was developed by statistical response surface methodology using central composite design. A second-order polynomial equation was generated to identify and predict singular versus combinatory effects of synergistic and antagonistic factors on chromatograph area. Predicted versus found outcomes overlapped, with enhanced area associated with the latter. DOE methodology was subsequently used to evaluate liquid chromatographic variable effects, e.g. flow rate, column temperature, and mobile phase composition on the response variable. Results demonstrate that combinatory AQbD-guided mass spectrometric/liquid chromatographic optimization significantly enhanced analytical sensitivity for Gln, thus enabling down-sized brain tissue sample volume procurement for quantification of this critical amino acid.

Optimization of tenocyte lineage-related factors from tonsil-derived mesenchymal stem cells using response surface methodology

BACKGROUND

In order to optimize the tenogenic differentiation of mesenchymal stem cells (MSCs), researchers should consider various factors. However, this requires testing numerous experimental settings, which is costly and time-consuming. We aimed to assess the differential effects of transforming growth factor beta-3 (TGF-β3) on the tenogenesis of tonsil-derived MSCs (T-MSCs) and bone marrow-derived MSCs (BM-MSCs) using response surface methodology (RSM).

METHODS

Bone marrow and tonsillar tissue were collected from four patients; mononuclear cells were separated and treated with 5 or 10 ng/mL of TGF-β3. A full factorial experimental design with a categorical factor of 0 was employed to study the effect of tension based on T-MSCs. Eighty-four trials were fitted with RSM and then used to obtain mathematical prediction models.

RESULTS

Exposure of T-MSCs and BM-MSCs to TGF-β3 increased the expression of scleraxis (SCX), tenomodulin (TNMD), decorin, collagen I, and tenascin C. Expression of most of these factors reached a maximum after 2-3 days of treatment. The model predicted that the values of the tenocyte lineage-related factors assessed would be significantly increased at 2.5 days of culture with 2.7 ng/mL of TGF-β3 for T-MSCs and at 2.3 days of culture regardless of TGF-β3 concentration for BM-MSCs.

CONCLUSIONS

This study demonstrated that the RSM prediction of the culture time necessary for the tenogenic differentiation of T-MSCs and BM-MSCs under TGF-β3 stimulation was similar to the experimentally determined time of peak expression of tenocyte-related mRNAs, suggesting the potential of using the RSM approach for optimization of the culture protocol for tenogenesis of MSCs.

Alfuzosin hydrochloride-loaded low-density gastroretentive sponges: development, in vitro characterization and gastroretentive monitoring in healthy volunteers via MRI

The current work aimed to develop low-density gastroretentive sponges loaded with alfuzosin HCl (ALF) to sustain the rate of drug release, improve its oral bioavailability and deliver it to the main site of absorption. Sponges were developed, according to a 2³ full factorial design, by compression of the lyophilized ALF-loaded hydroxypropylmethylcellulose (HPMC) or chitosan (CH) solutions. The influences of the polymer type, grade and concentration on the appearance, topography, porosity, density, in vitro ALF release, floating behavior, swelling, erosion, and mucoadhesive potential of the developed sponges were explored. Based on the desirability value, the best achieved system was selected. The gastroretentive potential of this system was evaluated in healthy male volunteers via MRI. Soft and flexible sponges were developed. They were characterized with interconnecting pores and channels and had excellent floating properties with respect to floating lag time and duration. Compared to HPMC-based sponges, CH-based ones exhibited higher porosity, larger pore diameters, lower bulk densities, higher drug release rates, larger swelling ratios, faster erosion rates and better mucoadhesive properties. MRI of magnetite-loaded best-achieved CH-based system (F8) ascertained the development of a promising gastroretentive system; exhibiting a gastric residence period of at least 5 h.

Optimal fermentation parameters for processing high quality African locust bean condiments

Fermented African locust bean (ALB) condiments are widely used to enhance the aroma and the taste of various dishes in West Africa. They are a good source of proteins. Sonru is one of the ALB condiments processed in Benin using a traditional starter called yanyanku. The variability in sonru processing unit operations (e.g. fermentation) presumably affects the quality (microbiological, biophysical and sensorial) of the final product. This study aimed at optimizing the fermentation step of sonru based on response surface methodology including three-factors [i.e. proportion of yanyanku, fermentation duration and thickness/depth of the layer of ALB (TALB)] and three-level factorial Box Behnken design with four central point replicates. The pH, softness of fermented cotyledons, Bacillus spp. and aerobic mesophilic bacteria count of sonru were evaluated. In addition, consumer acceptability was assessed by 7-hedonic box scale and Just About Right analysis. The pH had an upward trend with the increasing of all factors, and particularly Bacillus spp. count had similar trend with the fermentation duration and TALB whereas maximal penetration force (referred as the softness) had a downward trend with the fermentation duration. The optimal fermented ALB condiment resulted from processing conditions set at 1‰ of yanyanku, 24 h of fermentation and 8.5 cm for TALB. The optimized sonru appeared to be ideal in color, softness and taste. These findings can be used to improve fermented ALB condiments processing and better control the product quality in African countries. Further studies are needed to improve the odor of sonru.

Optimization of rendering process of poultry by-products with batch cooker model monitored by electronic nose

The best available controlled technology for transforming the disposal of animal by-products and mortalities is rendering. Two aspects of rendering process are mentioned in this research; product quality and emissions. A model of batch cooker with temperature, pressure and agitator speed controllers was designed and developed in order to optimize the process and to investigate the effect of changes in rendering conditions on quality of poultry by-product meal and also on pollutant emissions. An electronic nose system was designed and built based on metal oxide semiconductor sensors to monitor the gases emitted from batch cooker model. Also, GC-MS was used to identify the emitted components. In order to optimize the rendering process, response surface methodology was performed on temperature, cooking time and agitator speed variables. Results showed that the temperature of 140 °C (internal pressure equivalent to about 3.2 bar), the cooking time of 45 min and the agitator speed of 20 rpm optimized the process of batch cooking to maximize the percentage of protein and minimize the percentage of fat, moisture content, energy consumption and emission of pollutants. By GC-MS analysis, about 100 compounds include hydrocarbons, volatile fatty acids, sulfur-containing compounds, alcohols, ketones, aldehydes, and furans were observed in the emission of a batch cooker model. The major groups were organic acids and amides. Principle component analysis showed the most suitable sensors for detecting unpleasant odors from rendering plants.

Optimising of Scenedesmus sp. biomass production in chicken slaughterhouse wastewater using response surface methodology and potential utilisation as fish feeds

Production of Scenedesmus sp. biomass in chicken slaughterhouse wastewater (CSWW) is a promising alternative technique for commercial culture medium due to the high nutritional content of the generated biomass to be used as fish feeds. The current work deals with optimising of biomass production in CSWW using response surface methodology (RSM) as a function of two independent variables, namely temperature (10-30 °C) and photoperiod (6-24 h). The potential application of biomass yield as fish feeds was evaluated based on carbohydrate, protein and lipid contents. The results revealed that the best operating parameters for Scenedesmus sp. biomass production with high contents of carbohydrates, proteins and lipids were determined at 30 °C and after 24 h. The actual and predicted values were 2.47 vs. 3.09 g, 1.44 vs. 1.27 μg/mL, 29.9 vs. 31.60% and 25.75 vs. 28.44%, respectively. Moreover, the produced biomass has a high concentration of fatty acid methyl ester (FAME) as follows: 35.91% of C15:1; 17.58% of C24:1 and 14.11% of C18:1N9T. The biomass yields have 7.98% of eicosapentaenoic acid (EPA, C20:5N3) which is more appropriate as fish feeds. The Fourier transform infrared (FTIR) analysis of biomass revealed that the main functional groups included hydroxyl (OH), aldehyde (=C-H), alkanes and acyl chain groups. Scanning electron micrograph (SEM) and energy-dispersive X-ray spectroscopic analysis (EDS) indicated that the surface morphology and element distribution in biomass produced in BBM and CSWW were varied. The findings have indicated that the biomass produced in CSWW has high potential as fish feeds.

Optimization of Synthesis Conditions of Carbon Nanotubes via Ultrasonic-Assisted Floating Catalyst Deposition Using Response Surface Methodology

The growing use of carbon nanotubes (CNTs) in a plethora of applications has provided to us a motivation to investigate CNT synthesis by new methods. In this study, ultrasonic-assisted chemical vapor deposition (CVD) method was employed to synthesize CNTs. The difficulty of controlling the size of clusters and achieving uniform distribution&mdash;the major problem in previous methods&mdash;was solved by using ultrasonic bath and dissolving ferrocene in xylene outside the reactor. The operating conditions were optimized using a rotatable central composite design (CCD), which helped optimize the operating conditions of the method. Response surface methodology (RSM) was used to analyze these experiments. Using statistical software was very effective, considering that it decreased the number of experiments needed to achieve the optimum conditions. Synthesis of CNTs was studied as a function of three independent parameters viz. hydrogen flow rate (120⁻280 cm³/min), catalyst concentration (2⁻6 wt %), and synthesis temperature (800⁻1200 &deg;C). Optimum conditions for the synthesis of CNTs were found to be 3.78 wt %, 184 cm³/min, and 976 &deg;C for catalyst concentration, hydrogen flow rate, and synthesis temperature, respectively. Under these conditions, Raman spectrum indicates high values of (I_G/I_D), which means high-quality CNTs.