通过在发酵培养基中添加不同的外源营养物质及巨大芽孢杆菌的培养上清液,研究其对氧化葡萄糖酸杆菌生长及产2-酮基-L-古龙酸(2-KGA)的影响.结果表明,添加适量的谷氨酸单钠(MSG)、腺苷三磷酸(ATP)、含氮碱基、二氢叶酸和巨大芽孢杆菌的培养上清液都能够促进菌体增殖并提高2-KGA产量,而且2-KGA产量与生物量呈正相关.巨大芽孢杆菌的培养上清液促进菌体生长和产2-KGA的作用远大于以上各种外源营养物质.添加培养36 h的巨大芽孢杆菌胞外液后,氧化葡萄糖酸杆菌的菌落数和2-KGA产量分别是对照的13.39倍和8.81倍,而添加外源营养物质中促进作用最大的二氢叶酸后仅为对照的4.12倍和2.97倍.这表明,2-KGA产量的增加主要是通过促进氧化葡萄糖酸杆菌的菌体增殖实现,巨大芽孢杆菌的培养上清液促进氧化葡萄糖酸杆菌生长和产酸的机制不同于其他外源营养物质,可能是通过某种生物活性物质提高氧化葡萄糖酸杆菌菌群密度来实现.%The effect of several exogenous nutrient substances on the growth and 2-keto-L-gulonic acid (2-KGA) production of Cluconobacter oxydans was studied. It was found that additions of appropriate amount of monosodium glutamate (MSG), adenosine 5'-triphosphate (ATP), nitrogenous bases, dihydrofolic acid and the supernatant of Bacillus megaterium could promote the cell proliferation and 2-KGA production of G. Oxydans, and its biomass was positively correlated with the production of 2-KGA. The growth promoting effect on G. Oxydans by the supernatant of B. Megaterium was most significant among the exogenous nutrient substances mentioned above. After adding the supernatant of B. Megaterium cultured for 36h in the fermentation medium, the biomass concentration and 2-KGA production of G. Oxydans were 13.39 and 8.81 times higher than the control, respectively; while after adding dihydrofolic acid, which had the greatest promoting effect among the exogenous substances, the biomass concentration and 2-KGA production of G. Oxydans were only 4.12 and 2.97 times higher than the control, respectively. It suggests that the highly accumulation of 2-KGA might be due to the vigorous growth of G. Oxydans. The mechanism is different between the supernatant of B. Megaterium and the exogenous substances to the growth and the 2-KGA production of G. Oxydans, and the supernatant of B. Megaterium might contain some bioactive substances which increase the mass density of G. Oxydans.
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