Optimization of antifungal lipopeptide production from Bacillus sp. BH072 by response surface methodology

• Published in: The journal of microbiology 2014, 52(4), , pp.324-332
• Main Authors: Zhao, Xin, Han, Ye, Tan, Xi-qian, Wang, Jin, Zhou, Zhi-jiang
• Format: Article
• Language: English
• Subjects: Ammonium; ammonium chloride; Antibiotics; Antifungal Agents - metabolism; antifungal properties; Bacillus; Bacillus (bacteria); Bacillus - genetics; Bacillus - growth & development; Bacillus - metabolism; Biomedical and Life Sciences; Biotechnology - methods; calcium; carbon; Carbon sources; Chromatography; Chromatography, Liquid; citrates; containers; Culture Media - chemistry; Fatty acids; Fermentation; fructose; glucose; Hydrogen-Ion Concentration; iron; iturin; Life Sciences; lipopeptides; Lipopeptides - genetics; Lipopeptides - metabolism; Liquid chromatography; magnesium; manganese; Mass Spectrometry; Metabolites; metal ions; Microbiology; Microorganisms; nitrogen; Nitrogen sources; Optimization; Pathogens; Peptides; Peptides, Cyclic - genetics; Peptides, Cyclic - metabolism; Peptones; Pesticides; Plant diseases; potassium; response surface methodology; rhamnose; Scientific imaging; soybean meal; Soybeans; starch; Sucrose; Systems and Synthetic Microbiology and Bioinformatics; Technology, Pharmaceutical - methods; Temperature; Urea; xylose; zinc; 생물학
• ISSN: 1225-8873; 1976-3794
• DOI: 10.1007/s12275-014-3354-3

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 (Zn²⁺, Fe³⁺, Mg²⁺, Mn²⁺, Ca²⁺, and K⁺). The effects of these components on iturin A production were observed in LB medium. We selected sucrose, soybean meal, and Mg²⁺ 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% Mg²⁺. 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.