STUDY ON HIGH-DENSITY CULTURE OF AMMONIUM-RESISTANT N_2-FIXING BACTERIUM KLEBSIELLA OXYTOCA / 微生物学通报

ABSTRACT

Based on the physiological properties of ammonium-resistant N2-fixingbacterium ( Klebsiella oxytoca NG13/pMC73A), the fermentation technology of it was studied. The basic medium of high-density culture was established, with glucose as carbon source coupled with appropriate nitrogen source and inorganic salts. At the middle and late phase of culture, glucose and ammonia were added to supply carbon source and nitrogen source, stabilizing the pHat 6.5 ~ 6.8. Optimal level of dissolved oxygen was kept by controlling aeration and stirring rate. Bacterium number of Klebsiella oxytoca NG13/pMC73A reached 600 ~ 700 x 10s cfu/mL at the end of culture. Compared with previous technology, bacterium number was increased by more than ten-fold with a comparable culture period.