Statistical versus artificial intelligence -based modeling for the optimization of antifungal activity against Fusarium oxysporum using Streptomyces sp. strain TN71

A Streptomyces sp. strain TN71 was isolated from Tunisian Saharan soil and selected for its antimicrobial activity against phytopathogenic fungi. In an attempt to increase its anti–Fusarium oxysporum activity, GYM + S (glucose, yeast extract, malt extract and starch) culture medium was selected out of five different production media. Plackett–Burman design (PBD) was used to select yeast extract, malt extract and calcium carbonate (CaCO₃) as parameters having significant effects on antifungal activity, and a Box–Behnken design was applied for further optimization. The analysis revealed that the optimum concentrations for the anti–F. oxysporum activity of the tested variables were yeast extract 5.03 g/L, malt extract 8.05 g/L and CaCO₃ 4.51 g/L. Artificial Neural Networks (ANNs): the Multilayer perceptron (MLP) and the Radial basis function (RBF) were created to predict the anti–F. oxysporum activity. The comparison between experimental and predicted outputs from ANN and Response Surface Methodology (RSM) were studied. The ANN model presents an improvement of 14.73%. To our knowledge, this is the first work reporting the statistical versus artificial intelligence -based modeling for the optimization of bioactive molecules against mycotoxigenic and phytopathogenic fungi.     

Optimization of indigo production by a newly isolated Pseudomonas sp. QM

Optimization of indigo production process from indole using a newly isolated phenol‐degrading bacterial strain was performed by Plackett‐Burman design and response surface methodology. The strain designated as QM was identified as Pseudomonas sp. according to 16S rDNA analysis. Spectrum analysis of indole biotransformation products revealed the presence of indigo and a by‐product indirubin. To improve indigo yield, Plackett‐Burman design was used to select significant factors from 8 viriables. Then response surface methodology based on a 2³ central composite design was used to further optimize the transformation process. Under the optimal conditons, strain QM can produce 27.20 mg/l indigo after 24 h cultivation at 30 °C, which was 151.3% higher than that from the initial conversion condition. The results indicated that Pseudomonas sp. QM should be a potential candidate for indigo industial production. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)