LAUSR

Succinic acid is widely applied to chemical, pharmaceutical, food, and agricultural industries. With the rapid development of these industries, a great demand of succinic acid is required. The acid-tolerance and succinic acid production of Actinobacillus succinogenes strain were improved by using genome shuffling. Results showed that one modified strain AS-F32, with the best acid resistance and the highest succinic acid production, was obtained after 3 cycles of genome shuffling. The minimum growth pH of AS-F32 was 3.5, and the acid production and cell dry weight were 5.1 and 4.8 g/L in flask, improved 2.6 and 1.85 times over the start strain As-R2. Furthermore, the succinic acid yield of As-32 was 31.2 g/L and the dry cell weight was increased 44.4% by maintaining pH 4.8 with 7.0 M NH4OH in 5 L bioreactor, increased 1.1 times than the original strain As-R2.