Optimization of antifungal activity by Bacillus subtilis isolate CCASU 2021-4 using Response Surface Methodology

Abstract

Fungal infections represent an enormous load on the public especially with the development of resistance to the most currently used antifungal drugs in practice. In the present work, a bacterial isolate coded A3 was recovered from soil and was shown to express antagonistic activity against Candida (C.) albicans ATCC 10231. This isolate was identified as Bacillus (B.) subtilis subsp. spizizenii isolate CCASU 2021-4 using 16S ribosomal RNA sequencing. D-optimal design from response surface methodology (RSM) was used to optimize the environmental variables affecting the antifungal activity of the respective isolate. The optimum conditions were a temperature of 30 °C, a pH of 8, and an inoculum size of 5 x 10 7 cfu/mL, resulting in an enhancement in the antifungal activity by 1.2 fold. This is the first report, to the best of our knowledge, on an antifungal activity from B. subtilis subsp. spizizenii culture broth against human fungal pathogens along with its optimization through RSM.

An Anti-MRSA Phage From Raw Fish Rinse: Stability Evaluation and Production Optimization

“…The coefficient of variation (C.V.%) was 0.25. A C.V.% this low bespeaks the reliability of the experimental data ( El-Housseiny et al, 2016 ; El-Sayed et al., 2020a ; El-Sayed et al., 2020b ; El-Housseiny et al., 2021 ). How well the model describes the data was assessed by R 2 , the coefficient of determination.…”

“…Predicted R-squared (Pred R 2 ) was found to be 0.9504 and was tenably in agreement with its adjusted analogue (adj R 2 ) of 0.9986. Adequate precision ratio was 97.680, way greater than 4, indicating that this model can be used to navigate the design space ( El-Sayed et al., 2020a ; El-Housseiny et al., 2021 ).…”

“…How well the model describes the data was assessed by R 2 , the coefficient of determination. It was 0.9997, indicating that the model can explain 99.97% of the variability that may result in response ( El-Sayed et al., 2020a ; El-Housseiny et al., 2021 ). Predicted R-squared (Pred R 2 ) was found to be 0.9504 and was tenably in agreement with its adjusted analogue (adj R 2 ) of 0.9986.…”

“…One response value was monitored at the end of each run: phage titer in PFU/ml. The relationship between the factors was determined, and a polynomial cubic equation was fitted by the software using the data obtained from the experiments ( Bhaumik et al., 2013 ; González-Menéndez et al., 2018a ; El-Housseiny et al., 2021 ).…”

Statistical optimization of a podoviral anti-MRSA phage CCASU-L10 generated from an under sampled repository: Chicken rinse

“…The seventeen production runs were conducted in the lab (Table 2), and one response value, phage titer in PFU/ml, was recorded at the end. The factors' interaction was studied, and the software configured a polynomial reduced quadratic equation using the data gathered from the experiments (Bhaumik et al, 2013;Gonzaĺez-Meneńdez et al, 2018a;El-Housseiny et al, 2021).…”