培养方式对Xenorhabdus nematophila生长与抗菌活性的影响

Effect of culture mode on growth rate and antibiotic activity of Xenorhabdus nematophila

为了明确不同培养方式对Xenorhabdus nematophilaYL001生长和抗菌活性的影响,提高YL001菌株的抗菌活性。采用分批发酵方式研究了摇瓶与发酵罐培养对X.nematophilaYL001生长和抗菌活性的影响。实验结果表明:在通气量2.5 L/min、搅拌转速300 r/min条件下,发酵罐的体积氧传递系数KLa明显高于摇瓶,通气及供氧状况好于摇瓶,细胞生长及代谢旺盛,细胞生长量较摇瓶发酵增加了23.9%;但由于pH变化幅度大,抗菌物质的活性单位仅达到摇瓶的发酵水平,为229 U/mL。发酵罐pH控制初步研究表明,发酵过程中控制pH为7.5时,细胞生长量和抗菌活性达到23.71 g/L和290 U/mL,较不控制pH分别增加了21%和25%。通风对X.nematophilaYL001生长和抗菌物质的产生有较大的影响,发酵罐培养时通气及供氧状况好于摇瓶,有利于YL001菌株的生长和抗菌物质的产生。

To evaluate the influence of different culture mode on growth and antibiotics activity of Xenorhabdus nematophila YL001 and enhance the antibiotics activity, the fed-batch fermentation of X. nematophila YL001 was developed in shaking flask and fermenter. In 7 L fermenter, under agitation speed of 300 r/min, and aeration rate at 2. 5 L/min, the oxygen transfer coefficient （KLa） was higher than that in shaking flask, the dry cell weight was further increased by 23.2%. Moreover, the change of pH during fermentation in 7 L fermenter was higher than that in shaking flask, the antibiotic activity units reaching shaking flask fermentation level was 229 U/mL. Control of pH in fermenter demonstrated that when pH was controlled at 7.5, the dry cell weight and antibiotic activity were further increased to 23.71 g/L and 290 U/mL, and were improved by 21.0% and 25.0% , compared with fermentation at pH without control, respectively. Aeration had higher effects on the growth and antibiotics activity of X Fermentation in fermenter was beneficial to the cell growth and antibiotics production nematophila YL001 by the strain.