In this work

the semi-continuous succinic acid fermentation by Actinobacillus succinogenes CGMCC1593 from cane molasses with a novel two-stage and two-stream system was studied

in order to increase the succinic acid productivity.The fermentation conditions of the first stage

such as initial sugar concentration

medium addition volume

and time interval of each loading were optimized.Under the optimized condition the maximum succinic acid productivity (2.38 g·L-1·h-1) was increased by 111% and 114% compared with those obtained in batch and fed batch fermentation

respectively.In addition

the maximum succinic acid concentration (46.0 g·L-1)increased by 12.9% compared with that in batch fermentation

and reached a compatible level of that obtained in fed batch fermentation (36 h

48.8 g·L-1).This process was operated stably for 39 circles without any decreases in both succinic acid concentration and productivity.During the 39 operation circles

the fermentation time of each batch (stage 1 and stage 2)

the average succinic acid concentration

succinic acid productivity

succinic acid yield

and sugar conversion rate were 21—24 h

43.5 g·L-1

2.07 g·L-1·h-1

0.79 g·g-1

and 96.4%

respectively.