title: Optimization of antifungal lipopeptide production from Bacillus sp. BH072 by response surface methodology.
abstract: Antifungal lipopeptide produced by Bacillus sp. BH072 was extracted from fermentation liquor and determined as iturin A by liquid chromatography-mass spectrometry (LC-MS). For industrial-scale production, the yield of iturin A was improved by optimizing medium components and fermentation conditions. A one-factor test was conducted; fermentation conditions were then optimized by response surface methodology (RSM) to obtain the following: temperature, 29.5°C; pH 6.45; inoculation quantity, 6.7%; loading volume, 100 ml (in 500 ml flasks); and rotary speed, 150 rpm. Under these conditions, the mass concentration of iturin A was increased from 45.30 mg/ml to 47.87 mg/ml. The following components of the medium were determined: carbon sources (glucose, fructose, sucrose, xylose, rhamnose, and soluble starch); nitrogen sources (peptone, soybean meal, NH4Cl, urea, and ammonium citrate); and metal ions (Zn(2+), Fe(3+), Mg(2+), Mn(2+), Ca(2+), and K(+)). The effects of these components on iturin A production were observed in LB medium. We selected sucrose, soybean meal, and Mg(2+) for RSM to optimize the conditions because of several advantages, including maximum iturin A production, high antifungal activity, and low cost. The optimum concentrations of these components were 0.98% sucrose, 0.94% soybean meal, and 0.93% Mg(2+). After iturin A production was optimized by RSM, the mass concentration reached 52.21 mg/ml. The antifungal specific activity was enhanced from 350.11 AU/mg to 513.92 AU/mg, which was 46.8% higher than the previous result. The present study provides an important experimental basis for the industrial-scale production of iturin A and the agricultural applications of Bacillus sp. BH072.
authors.affiliation: School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, P. R. China.
authors.forename: Xin
authors.initials: X
authors.lastname: Zhao
authors.forename: Ye
authors.initials: Y
authors.lastname: Han
authors.forename: Xi-qian
authors.initials: XQ
authors.lastname: Tan
authors.forename: Jin
authors.initials: J
authors.lastname: Wang
authors.forename: Zhi-jiang
authors.initials: ZJ
authors.lastname: Zhou
mesh_terms: D000935:Antifungal Agents / Q000378:metabolism*; D001407:Bacillus / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D001709:Biotechnology / Q000379:methods; D002853:Chromatography, Liquid; D003470:Culture Media / Q000737:chemistry; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D055666:Lipopeptides / Q000235:genetics / Q000378:metabolism*; D013058:Mass Spectrometry; D010456:Peptides, Cyclic / Q000235:genetics / Q000378:metabolism*; D013678:Technology, Pharmaceutical / Q000379:methods; D013696:Temperature
chemical_list: D000935:Antifungal Agents; D003470:Culture Media; D055666:Lipopeptides; D010456:Peptides, Cyclic; C013579:iturin A