Predictive Modeling of Psychrotrophic Bacillus cereus

1993 ◽  
Vol 56 (8) ◽  
pp. 684-688 ◽  
Author(s):  
JANICE M. BAKER ◽  
MANSEL W. GRIFFITHS
Keyword(s):  
Bacillus Cereus ◽  
Response Surface ◽  
Water Activity ◽  
Brain Heart Infusion ◽  
Toxin Production ◽  
Plate Counts ◽  
Toxin Assay ◽  
Predicted Values ◽  
Experimental Values ◽  
Psychrotrophic Strain

Response surface analysis was used to determine the effects and interactions of water activity (0.965 to 0.995), pH (5.8 to 8.0), temperature (6 to 38°C), glucose concentration (0 to 1.8%), and starch concentration (0 to 0.625%) on the growth of and toxin production by a psychrotrophic strain of Bacillus cereus in brain heart infusion broth. Growth was measured by monitoring optical density and plate counts, toxin production was assayed by an immunological method (BCET-RPLA toxin assay) and cytotoxicity with Vero and HEp-2 cells. Regressions were performed using response surface techniques, on Growth, LnGrowth, RPLA, LnRPLA, Vero, LnVero, and HEp-2; quadratic predictive equations for growth and toxin production were obtained. The results indicate the factors that had the greatest influence on both growth and toxin production were water activity and temperature. Predicted values obtained from the model were in good agreement with experimental values.

Toxin Production by Psychrotrophic Bacillus spp. Present in Milk

1990 ◽  
Vol 53 (9) ◽  
pp. 790-792 ◽  
Author(s):  
M. W. GRIFFITHS
Keyword(s):  
Bacillus Cereus ◽  
Brain Heart Infusion ◽  
Bacterial Count ◽  
Toxin Production ◽  
Latex Agglutination ◽  
Brain Heart Infusion Broth ◽  
Agglutination Assay ◽  
Bacillus Spp ◽  
Latex Agglutination Assay

Using a reversed passive latex agglutination assay, about 85% of psychrotrophic Bacillus spp. tested were shown to produce diarrhoegenic toxin during growth on brain heart infusion broth at 25°C. The majority of these strains were identified as Bacillus cereus or cereus-related strains. However, a number of other species was capable of synthesizing the toxin. Further investigation of four psychrotrophic Bacilli showed that the toxin was produced during growth in milk at temperatures ranging from 6 to 21°C. Toxin production increased with increasing temperatures and was not synthesized in appreciable quantities until the bacterial count exceeded 1 × 107 cfu/ml.

scholarly journals Modeling of Degradation of Diazo Dye in Swirl-Flow Photocatalytic Reactor: Response Surface Approach

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1418
Author(s):  
Waleed Jadaa ◽  
Anand Prakash ◽  
Ajay K. Ray
Keyword(s):  
Light Intensity ◽  
Response Surface ◽  
Swirl Flow ◽  
Quadratic Model ◽  
Catalyst Loading ◽  
Random Pattern ◽  
Photocatalytic Reactor ◽  
Degradation Reactions ◽  
Predicted Values ◽  
Experimental Values

Photocatalytic degradation of Direct Blue 15 (DB15), an azo dye, was studied using a swirl-flow monolithic reactor under UV irradiation. The degradation reactions were carried out to investigate effects of initial dye concentration, catalyst loading, and light intensity at an optimal pH. The experiments were designed and mathematically modelled by CCD-RSM (central composite design-response surface methodology) approach. It was found that the selected parameters significantly affect DB15 degradation. In terms of the linear term, catalyst loading and light intensity had a synergistic effect, while dye concentration registered the opposite effect. Strong interaction was observed between catalyst loading and both light intensity and initial dye concentration compared with the interaction of light intensity and initial dye concentration. Based on the experimental results, a quadratic model was developed to predict the percentage removal of DB15. The predicted values of the model were in good agreement with the experimental values (R2 = 0.987), indicating the model fits well for the parameter space for which experiments were performed. According to diagnostic plots, the model credibility was valid because its residuals were distributed normally and exhibited a random pattern based on their examination versus the predicted values. The results revealed that the initial dye concentration and catalyst concentration have a significant effect on the mineralization time.

Cell Culture Detection and Conditions for Production of a Bacillus cereus Heat-Stable Toxin

1991 ◽  
Vol 54 (4) ◽  
pp. 272-276 ◽  
Author(s):  
RICHARD A. SZABO ◽  
JOAN I. SPEIRS ◽  
MUMTAZ AKHTAR
Keyword(s):  
Molecular Weight ◽  
Cell Culture ◽  
Bacillus Cereus ◽  
Morphological Changes ◽  
Brain Heart Infusion ◽  
Toxin Production ◽  
Cell Multiplication ◽  
Vacuole Formation ◽  
Heat Stable ◽  
Low Levels

In rice, milk, and brain-heart-infusion cultures, 17 of 67 Bacillus cereus strains produced a heat-stable toxin causing morphological changes in cultures cells. All of the positive strains were associated with illness, eight with the emetic syndrome. Time-temperature studies indicated that toxin production was optimum at 25 to 30°C after 18 h in shaking culture, but low levels were produced at 15°C. Effects in cells included granulation, vacuole formation, cell rounding, acid production, and arrested cell multiplication. Of seven cell lines tested, Int 407, CHO, and HEp-2 were equally the most sensitive with the former being preferred for ease of interpreting results. The observed toxin had a molecular weight of about 14,000 and a pI of 5.9 as determined by Superose 12 chromatography and Mono P ion-exchange chromatofocusing, respectively.

scholarly journals The Optimization of Parameters for the Spray Drying Process of Wood Apple Extract using Response Surface Methodology

2019 ◽  
Vol 9 (2) ◽  
pp. 4528-4535
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Spray Drying ◽  
Sensory Quality ◽  
Drying Process ◽  
Nutritional Components ◽  
Predicted Model ◽  
Input Variables ◽  
Predicted Values ◽  
Experimental Values

Wood apple is a fruit, which containing many nutrient values and bioactive compounds. In the present study, The response surface methodology (RSM) was used to optimize the input variables of the spray drying process. Three coded independent variables viz. input dry substance concentration (X1 ), input flow (X2 ), spray drying temperature (X3 ), corresponds to the encoded variables Z1 (from 20 to 24 %), Z2 (from 5.35 to 6.72 mL/min.), Z3 (from 140 to 160oC). The R2 correlation coefficient between the experimental values and the predicted values from the model up to 0.967 indicated the satisfactorily of the predicted model. Three optimal input parameters to get the highest efficiency of dry matter recovery (51.80 %) were derived at Z1 = 24 %, Z2 = 5.35 mL/min., Z3 = 160oC. The powder product obtained has a good sensory quality, high contents of antioxidants and nutritional components.

Process Optimization of Microwave Drying Sludge with Response Surface Methodology

2011 ◽  
Vol 396-398 ◽  
pp. 1269-1272 ◽  
Author(s):  
Mu Xin Han ◽  
Dong Mei Li ◽  
Yu Jie Feng ◽  
Yu Fei Tan
Keyword(s):  
Response Surface Methodology ◽  
Moisture Content ◽  
Response Surface ◽  
Microwave Drying ◽  
Tree Bark ◽  
Treatment Efficiency ◽  
Optimum Parameters ◽  
Predicted Values ◽  
Experimental Values ◽  
The Relationship

To enhance further treatment efficiency of the sludge, a process microwave drying of sludge was optimized using response surface methodology (RSM). A quadratic polynomial mathematical model was developed through Box-Behnken experimental design to describe the relationship between tested variables and moisture content of sludge. The experimental values were found to be in accordance with the predicted values, the correlation coefficient is 0.9203(P < 0.001). Estimated optimum parameters were as follows: The sludge: tree bark is 58:1, microwave power is 630w and processing time is 5.32 minutes. Under these conditions, a lowest moisture content of sludge (49.12%) after microwave drying was reached.

Bacillus cereus: Aerobic Growth Kinetics

1993 ◽  
Vol 56 (3) ◽  
pp. 211-214 ◽  
Author(s):  
ROBERT C. BENEDICT ◽  
TIMOTHY PARTRIDGE ◽  
DONNA WELLS ◽  
ROBERT L. BUCHANAN
Keyword(s):  
Sodium Chloride ◽  
Bacillus Cereus ◽  
Sodium Nitrite ◽  
Variable Temperature ◽  
Brain Heart Infusion ◽  
Growth Curves ◽  
Food Storage ◽  
Lag Phase ◽  
Generation Times ◽  
Plate Counts

Three strains of Bacillus cereus were cultured in brain heart infusion medium aerobically under conditions of variable temperature (5 to 42°C), sodium chloride concentrations (0.5–5%), pH (4.5 - 7.5), and sodium nitrite concentration (0 mg/L - 200 mg/L) to simulate conditions of normal and adverse food storage. Cultures were sampled at selected times, and plate counts were used to calculate growth curves under each condition. None of the three strains grew at 5°C, but growth did occur slowly at 8°C, and was most rapid at a temperature of 37°C. Growth occurred in media without additives in all pH's examined between 8 and 42°C. Decreasing the pH and increasing levels of sodium chloride and sodium nitrite increased the lag phase and generation times of the organism.

Optimization of Nigerian Restaurant Waste Cooking Biodiesel Reaction Parameters using Response Surface Methodology

2014 ◽  
Vol 3 (4) ◽  
pp. 21-33
Author(s):  
M.A. Waheed ◽  
O.D. Samuel ◽  
B.O. Bolaji ◽  
O.U. Dairo
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Maximum Yield ◽  
Waste Cooking Oil ◽  
Molar Ratio ◽  
Optimization Parameters ◽  
Predicted Values ◽  
Experimental Values ◽  
Restaurant Waste ◽  
Good Agreement

The present work deals with the production of biodiesel from Nigerian restaurant waste cooking oil (NRWCO) and the optimization of the parameters that influences the alkaline transesterification of NRWCO into biodiesel using response surface methodology. The optimization parameters like oil: oil/methanol molar ratio, catalyst amount and reaction time were done using Design Expert 6.06 software. It was found that the maximum yield of biodiesel was obtained in 79.8 min for 1: 5.9, oil: methanol ratio, 1.2 wt. % KOH amount. A total of 20 experiments using Central Composite Design were carried out. The R2, adjusted R2 and predicted R2 values were 0.982, 0.9657 and 0.9088 respectively show that the experimental values are in good agreement with the predicted values. The properties of biodiesel at the optimized parameters, thus, produced confirm to the ASTM, EN and BIS specifications, making it an ideal alternative fuel for diesel engine.

Optimization studies on Biosorption of Copper (II) by Crab Shell Using Response Surface Methodology(RSM)

2010 ◽  
Vol 5 (1) ◽  
Author(s):  
Sudesh S ◽  
Meenakshi M ◽  
Sheeja R.Y ◽  
Thanapalan Murugesan
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Crab Shell ◽  
Box Behnken Design ◽  
Initial Ph ◽  
Predicted Values ◽  
Experimental Values ◽  
The Individual ◽  
Maximum Removal ◽  
Good Agreement

In the present work, crab shell was used as the biosorbent to remove copper from aqueous solution. Batch experiments were performed at different initial copper concentration of copper solutions (1-40 g/l), initial pH (2-9), temperature (20-400°C), and biosorbent dosages (2-10 g/l). The maximum removal of copper using crab shell occurred at a pH of 3 and at a temperature of 400°C using an optimum biosorbent dosage of 5 g/l. A mathematical model was proposed to identify the effects of the individual interactions of these variables on the biosorption of copper. The results have been modeled using response surface methodology using a Box-Behnken design. The response surface method was developed using three levels (-1, 0, +1) with the above mentioned four factors. The second order quadratic regression model fitted the experimental data with Prob > F to be < 0.0001. The experimental values were found to be in good agreement with the predicted values, with a satisfactory correlation coefficient of R2 = 0.9999.

scholarly journals Optimization of Reflux Conditions for Total Flavonoid and Total Phenolic Extraction and Enhanced Antioxidant Capacity in Pandan (Pandanus amaryllifoliusRoxb.) Using Response Surface Methodology

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Ali Ghasemzadeh ◽  
Hawa Z. E. Jaafar
Keyword(s):  
Response Surface Methodology ◽  
Antioxidant Capacity ◽  
Response Surface ◽  
Total Phenolic ◽  
Extraction Temperature ◽  
Solid Ratio ◽  
Central Composite Experimental Design ◽  
Operation Parameters ◽  
Predicted Values ◽  
Experimental Values

Response surface methodology was applied to optimization of the conditions for reflux extraction of Pandan (Pandanus amaryllifoliusRoxb.) in order to achieve a high content of total flavonoids (TF), total phenolics (TP), and high antioxidant capacity (AC) in the extracts. Central composite experimental design with three factors and three levels was employed to consider the effects of the operation parameters, including the methanol concentration (MC, 40%–80%), extraction temperature (ET, 40–70°C), and liquid-to-solid ratio (LS ratio, 20–40 mL/g) on the properties of the extracts. Response surface plots showed that increasing these operation parameters induced the responses significantly. The TF content and AC could be maximized when the extraction conditions (MC, ET, and LS ratio) were 78.8%, 69.5°C, and 32.4 mL/g, respectively, whereas the TP content was optimal when these variables were 75.1%, 70°C, and 31.8 mL/g, respectively. Under these optimum conditions, the experimental TF and TP content and AC were 1.78, 6.601 mg/g DW, and 87.38%, respectively. The optimized model was validated by a comparison of the predicted and experimental values. The experimental values were found to be in agreement with the predicted values, indicating the suitability of the model for optimizing the conditions for the reflux extraction of Pandan.

Sign in / Sign up

Export Citation Format

Share Document