Abstract

Statistics based experimental designs were used to optimize the medium for antifungal active substances production from a newly isolated Paenibacillus polymyxa Cp-S316 in shaker flask cultivation. The medium components having significant effect on the production were first identified using a fractional factorial design. Then steepest ascent method was employed to approach the experimental design space, followed by an application of response surface methodology for further optimization. A quadratic model was found to fit the antifungal active substances production. Response surface analysis revealed that the optimum values of the tested variables for the production of active substances were 12.3 (g/l) lactose, 17.5 (g/l) peptone, 0.4 (g/l) sodium nitrate, 4.5 (g/l) magnesium sulfate and 100 (g/l) potato. A production of 4687.71 μg/ml, which was in agreement with the prediction, was observed in verification experiment. In comparison to the production of basal medium, 3.05-fold increase had been obtained.

Keywords: Paenibacillus polymyxa Cp-S316; Fractional factorial design; Steepest ascent method; Central composite design; Response surface methodology

Article Outline

1. Introduction

2. Methods

2.1. Microorganism

2.2. Growth medium and culture conditions

2.3. Analytical methods

2.4. Experimental design

2.4.1. Fractional factorial design (FFD)

2.4.2. Central composite design (CCD)

2.5. Antifungal activity in vitro

3. Results and discussion

3.1. Optimization by factional factorial design

3.2. Optimization by steepest ascent path

3.3. Optimization by response surface methodology

3.4. Validation of the experimental design

3.5. Antifungal activity

4. Conclusions

Acknowledgements

References