致病杆菌D43菌株产素培养基及发酵条件

Cultural Medium and Fermentation Conditions of Xenorhabdus sp.Strain D43

对致病杆菌产生抗生素的发酵培养基和发酵条件进行了研究，同时对该菌代谢过程pH值、还原糖、总糖、氨基氮与抗生素产量的关系进行了分析。通过筛选，确定了对该菌产素有利的碳源、氮源和无机盐。用正交试验初步确定了该菌产素的最佳发酵培养基和条件为（g／L）：麦芽糖5g，牛肉胨10g，牛肉膏5g，CaCl25g，KNO30．2g。发酵培养基的起始pH值在6．0～8．0、种龄16h、摇瓶装量25—150ml／500ml的条件下，培养72h可获得较高的抗生素产量。产素量与菌代谢过程中pH、还原糖、总糖和氨基氨的变化有一定关系。通过培养基和培养条件的研究使该菌的产抗生素能力提高了46．67％。

The optimum medium and culture conditions of the Xenorhabdus sp. D43 strain were studied. The relationships between antibiotic activity and pH, reducing sugar, total sugar, amino-nitrogen in process of fermentation were analyzed. The optimal medium was maltose 0.5 %, peptone 1.0 %, beef extract 0.5%, CaCl2 0.5% and KNO3 0.02%. Stock cultured for 16 h and primary pH of medium ranged from 6.0 to 8.0, fermentation for 72 h were of benefit to the yield of antibiotic. The pH, reducing sugar and total sugar in process of fermentation were related to the antibiotic yields. The yield of antibiotic increased to 46.67 % compared with the basic medium.