Study On Recovery Process Of Succinic Acid From Fermentation Broth

Succinic acid is a kind of chemical materials widely used in the food,pharmaceutical,biodegradable material,and fine chemical fields.With the energy and environment issues being more and more emergent,succinic acid from microorganism borth is a potential resource for replacing petrochemical reserve.However,producing succinic acid with high purify but low cost from fermentation broth is an important issue to be resolved.This study is focused on the technology of isolation and purification of succinic acid from fermentation broth of Escherichia coli NZN111.1.Pretreatment of the fermentation broth.The cells and particles in fermentation broth were removed by centrifugation.Then the pH was adjusted to 6.8 and decolorizated by 3.5%(w/v)activated carbon for 40 min with an agitation speed of250 rpm at 30?C.The results showed that the decoloration rate is 98.08% and loss rate of succinic acid 3.02%.2.Isolation of succinic acid by urea-succinic acid cocrystallization from borth.Control variable method was used to optimize the mass ratio of urea to succinic acid,time,temperature and pH.The results showed that the optimal conditions were as follows: mass ratio of urea to succinic acid is 3.2:1,temperature 4 ? C and crystallization time 12 h which gave the recovery of succinic acid 92.5% containing no acetic acid,pyruvic acid,glucose,protein and other impurities.The effects of alcohols on the isolation of succinic acid from cocrystallization products were also inverstigated and methanol was selected for the extraction solution.Finally the extracts was isolated and purified by column chromatography of strong acid cation exchange resin(732 type)and purified succinic acid was obtained(>99% in purification).3.Isolation and purification of succinic acid by cooling crystallization.Cooling crystallization was adapted to reduce the consume of urea prior to the cocrystallization.The results indicated that the recovery and the purification of succinic acid is 73.4% and 99.05%,respectively,at the condition of pH 2,temperature 8 ? C and time of crystallization 4h.The subsequent condiction of cocrystallization was as follows: ratio of urea to succinic acid is 4:1,pH 2,and the time of crystallization 18 h at 4?C which gave a recovery of succinic acid 97.34% and reduced dramatically the consume of urea.4.The synthesis of succinimide.The results indicated that the rate of urea to succinic acid was adjusted to 1:2,4.2% phosphite,reaction 6 h at 195 ?C,the yeild of succinimide is 80%.The mentioned technology can avoid the process of co-crystallization of succinic acid-urea and greatly reduced the consume of methanol and water.