Statistical experimental design was used to optimize the concentration of trace elements for production of antifungal compound, 2,4-diacetylphloroglucinol (DAPG), from fluorescent pseudomonad R62 in shake-flask cultivation. The selection of the trace metal ions, influencing DAPG production, was done using Plackett-Burman design (PBD). Only Zn2+, Mn2+ and MoO42- were the most significant components (p < 0.05). A quadratic model was used to fit the response. Application of response surface methodology (RSM) revealed that the optimum values of the salts of the trace elements Zn2+ (ZnSO4 center dot 7H(2)O), Mn2+ (MnCl2 center dot 4H(2)O), and MoO42- (Na2MoO4 center dot 2H(2)O) were 83,42 and 135 mu M, respectively, to achieve 125 mg/L of DAPG, which was nearly 13-fold more compared to its production in basal synthetic medium in shake flask. The studies in 14 L bioreactor resulted in 135 mg/L of DAPG at the end of 36 h of cultivation. The culture broth containing 125 mg/L of DAPG was found to be sufficient for keeping the bio-inoculant viable in non-sterile talcum powder-based formulations (which contained 25 mu g DAPG/g carrier) when stored at 28 degrees C for 6 months. The structure of the purified DAPG was confirmed using H-1 NMR and mass spectrometry. (C) 2010 Elsevier Inc. All rights reserved.