伊枯草菌素A高产菌株的筛选鉴定及发酵工艺研究

该研究采用平板对峙法及高效液相色谱（HPLC）法从土壤中筛选高产伊枯草菌素A（iturin A）的菌株，通过分子生物学技术对其进行菌种鉴定，并以iturin A产量为评价指标，对培养基成分及发酵条件进行研究。结果表明，筛选得到1株高产iturin A的菌株，编号为ND，并鉴定其为贝莱斯芽孢杆菌（Bacillus velezensis）；其产iturin A的最佳培养基成分为豆粕粉120 g/L、酵母浸粉16 g/L、L-谷氨酸钠1 g/L、甘油70 mL/L、MgSO4·7H2O 0.5 g/L、KH2PO4 1.0 g/L，FeSO4·7H2O 0.15 mg/L、MnSO4·H2O 5 mg/L、CuSO4·5H2O 0.16 mg/L；最佳培养条件为装液量12%、初始pH值8、接种量10%、培养温度28 ℃、培养时间5 d。在此最优条件下，菌株ND的iturin A产量为4.76 g/L，是优化前（0.35 g/L）的13.6倍。

Screening,identification and fermentation technology of high yield iturin A-producing strain

The high yield iturin A-producing strains were screened from soil by plate confrontation method and HPLC, and identified by molecular biology technology. Taking iturin A yield as the evaluation index, the composition of culture medium and fermentation conditions were studied. The results showed that a strain with high yield of iturin A was screened, numbered as ND, and identified as Bacillus velezensis. The optimum medium components for producing iturin A were soybean meal powder 120 g/L, yeast extract powder 16 g/L, L-sodium glutamate 1 g/L, glycerol 70 ml/L, MgSO4·7H2O 0.5 g/L, KH2PO4 1.0 g/L, FeSO4·7H2O 0.15 mg/L, MnSO4·H2O 5 mg/L, CuSO4·5H2O 0.16 mg/L. The optimal culture conditions were liquid volume 12%, initial pH 8, inoculum 10%, culture temperature 28 ℃ and time 5 d. Under the optimal conditions, the iturin A yield of the strain ND was 4.76 g/L, which was 13.6 times than that before optimization (0.35 g/L).