Antimicrobial protein production by Bacillus amyloliquefaciens MBL27: An application of statistical optimization technique

Abstract

The applicability of the Taguchi DOE (design of experiment) methodology for optimization of medium composition for maximum antimicrobial protein (AMP) production by Bacillus amyloliquefaciens MBL27 has been demonstrated in the present study. The influence of individual factors and the relationships between the factors and their levels were established. Three factors viz, glucose, triammonium citrate and K2HPO4, each at three levels were selected and an orthogonal array (OA) layout of L27 containing 27 well-defined experiments were performed. Two response variables (bacterial growth and inhibitory activity of the AMP) were measured. Maximum AMP production was achieved at a concentration of 1.0% glucose, 0.25% triammonium citrate and 0.2% K2HPO4. The experiments conducted provided basic information to improve the efficiency of AMP production and supported the analysis of main effect of each constituent in the medium. This study is therefore another example of the application of the Taguchi methodology for improvement of biological processes. Key words: Antimicrobial protein, Bacillus amyloliquefaciens, optimization, response surface methodology (RSM), Taguchi design.