根癌农杆菌与嗜烟碱节杆菌降解烟碱特性的对比分析

Comparison of Nicotine Degrading Behavior Between Agrobacterium tumefaciens and Arthrobacter nicotinovorans

以嗜烟碱节杆菌(Arthrobacter nicotinovorans)为参照菌株,研究了1株新的烟碱降解菌根癌农杆菌B5(Agrobacterium tumefaciens B5)降解烟碱的特性。结果表明,在烟碱液体培养基中,根癌农杆菌B5的培养液呈灰白色,而嗜烟碱节杆菌的培养液呈蓝黑色;在烟碱固体培养基中,根癌农杆菌在生长初期菌落无明显颜色变化,呈灰白色,随着时间的延长,菌落和平板的颜色逐渐转为棕红色;而嗜烟碱节杆菌在生长前期即有明显的蓝色物质生成,随着时间的延长,菌落生长处平板的颜色逐渐由深蓝变至蓝黑色,最终整个平板又转至深棕黄色,这表明两者的代谢机理可能存在显著差异。通过液体培养基烟碱降解试验发现,根癌农杆菌B5在培养10 h左右进入对数生长期,而嗜烟碱节杆菌培养6 h后即进入对数生长期,且菌体生长量大于前者;但培养18 h后,根癌农杆菌降解烟碱的效率与经典菌株嗜烟碱节杆菌相当。

The nicotine degrading behavior of a new strain capable of degrading nicotine, Agrobacterium tumefaciens B5, was studied and compared with that of Arthrobacter rticotinovorans, The results showed that： in the liquid medium of nicotine, the culture solution containing Agrobacterium tumefaciens B5 was grey, while that containing Arthrobacter nicotinovorans was blue-black; in the solid medium of nicotine, the colony of Agrobacterium tumefaciens was grey at early growth stage, after that the color of colonies and plate turned gradually into brown-red with the prolongation of time; however, some blue substances were found at the early growth stage of Arthrobacter nicotinovorans, at the place where the colony was growing the color of the plate changed gradually from dark blue to blue-black, and eventually the entire plate turned into dark brown-yellow. It suggested that there possibly be significant differences of metabolic mechanism between the two bacteria. The results of nicotine degradation test in liquid medium indicated that Agrobacterium tumefaciens B5 entered its logarithmic growth phase in about 10 hours, while Arthrobacter nicotinovorans in 6 hours, and the amount of thalli of B5 was higher than that of Arthrobacter nicotinovorans. However, the nicotine degradation efficiency of the two bacteria was similar after culture for 18 hours.