耐铵型产琥珀酸放线杆菌的选育

以Actinobacillus succinogenes NJ113为出发菌株,经硫酸二乙酯(DES)诱变,在含8～20 g/L硫酸铵平板中筛选到一株耐铵型突变株YZ25,该菌株在含8 g/L硫酸铵培养基中厌氧发酵,琥珀酸产量达32.68 g/L,比出发菌提高了180.5%,对葡萄糖收率达65.4%,副产物乙酸、甲酸产量分别下降3.5%、28.7%,琥珀酸/乙酸比值由0.63提高到2.5。在7.5 L发酵罐中,用氨水调节pH分批实验,发酵34 h琥珀酸产量达27.13 g/L,较出发菌株提高了85.3%。

Breeding of NH4+-tolerant mutants of Actinobacillus succinogenes for succinic acid production

The succinic acid producing strain Actinobacillus succinogenes NJll3 was selected as the parent strain. After DES treatments, a NH4^＋ -tolerant mutant YZ25 was obtained in medium containing 8--20 g/L （NH4）2O4. When fermentation was conducted in anaerobic bottles containing 8 g/L （NH4）2SO4, the succinic acid concentration of mutant YZ25 reached 32.68 g/L, which was increased by 180.5 % compared with that of the parent strain. The yield of succinic acid was 65.4%, and by-product formic acid and acetic acid concentration was decreased by 3.5% and 28.7%, respectively. And the mass ratio of succinic acid/acetic acid increased from 0.63 to 2.5. When NH4OH was used to control the culture pH of batch fermentation for 34 h in a 7.5 L stirred bioreactor, the succinic acid concentration（27.13 g/L） was increased by 85.3 %.