Zhao Xin, Han Ye, Tan Xi-qian, Wang Jin, Zhou Zhi-jiang
School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, P. R. China.
J Microbiol. 2014 Apr;52(4):324-32. doi: 10.1007/s12275-014-3354-3. Epub 2014 Feb 17.
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.
从芽孢杆菌属BH072发酵液中提取了抗真菌脂肽，并通过液相色谱 - 质谱联用（LC - MS）测定为伊枯草菌素A。为实现工业化规模生产，通过优化培养基成分和发酵条件提高了伊枯草菌素A的产量。进行了单因素试验；然后采用响应面法（RSM）对发酵条件进行优化，得到以下结果：温度29.5°C；pH 6.45；接种量6.7%；装液量100 ml（在500 ml烧瓶中）；转速150 rpm。在此条件下，伊枯草菌素A的质量浓度从45.30 mg/ml提高到47.8 mg/ml。测定了培养基的以下成分：碳源（葡萄糖、果糖、蔗糖、木糖、鼠李糖和可溶性淀粉）；氮源（蛋白胨、豆粕、NH4Cl、尿素和柠檬酸铵）；以及金属离子（Zn(2+)、Fe(3+)、Mg(2+)、Mn(2+)、Ca(2+)和K(+)）。在LB培养基中观察了这些成分对伊枯草菌素A产量的影响。由于具有包括伊枯草菌素A产量最高、抗真菌活性高和成本低等几个优点，我们选择蔗糖、豆粕和Mg(2+)进行RSM条件优化。这些成分的最佳浓度分别为0.98%蔗糖、0.94%豆粕和0.93% Mg(2+)。通过RSM优化伊枯草菌素A的生产后，质量浓度达到52.21 mg/ml。抗真菌比活性从350.11 AU/mg提高到513.92 AU/mg，比之前的结果高46.8%。本研究为伊枯草菌素A的工业化规模生产和芽孢杆菌属BH072在农业上的应用提供了重要的实验依据。
