Study On Recovery Of Succinic Acid From Fermentation Broth Using Reactive Extraction And Aqueous Two-phase System

Succinic acid is one of important C4platform chemicals. As an alternative chemicalsynthesis, fermentative production of succinic acid is growing concern by the world. In thisstudy, in order to improve the recovery yield of succinic acid from fermentation broth, thereactive extraction (RE) and aqueous two-phase system (ATPS) were investigated to recoverysuccinic acid from fermentation broth.For reactive extraction, trioctylamine and octanol was used as extraction agent to extractsuccinic acid form fermentation broth. The pre-treatment of fermentation broth as well aspreparation of succinic acid diammoniumsalt using ammonia were investigated. Resultsshowed that the rate of succinic acid extraction from fermentation broth pre-treated by cationexchange resin reached91.3%, which was higher than that of by sulfuric acid. Ammonia wasan excellence re-extraction agent and the extractant (trioctylamine and octanol) could bereusable. When extractant was recycled five times, both average rates of extraction andre-extraction were90.4%and94.8%, respectively, indicating no obvious changes. Succinicacid diammonium salt with the purity of97.8%was obtained from strip liquor by ethanolprecipitation.For aqueous two-phase system (ATPS), various kinds of hydrophilic solvent andinorganic salts were used to extract succinic acid from fermentation broth. Theacetone/ammonium sulfate ATPS was investigated in details, including phase diagram, effectsof phase composition and pH on partitions, the removal of cells and proteins from thefermentation broth, as well as the recovery of ammonium sulfate. Under the optimizedconditions that the aqueous two-phase system was composed of35%(w/w) acetone and15%(w/w) ammonium sulfate, and pH of fermentation broth was regulated to2, the recovery ofsuccinic acid attained94.4%, the removal of glucose, cells and proteins were93.6%,98.1%and78.5%, respectively. Succinic acid with the purity of98.7%was get from acetonephase by concentration crystallization. The recovery of ammonium sulfate in the bottle phasereached95.9%when methanol was added to the salt-rich phase.For extraction succinic acid from fermentation broth by Actinobacillus succinogenes, therecovery rate of succinic acid diammonium salt was77.1%using RE, while the recovery rateof succinic acid was91.4%using ATPS. The above two methods have advantages of lowenergy consumption, less waste discharge and easy to enlarge in industry. The higher price ofsuccinic acid diammonium salt could indirectly reduce costs when RE was used to extraction.And ATPS, as a new method insuccinic acidextraction, has exploitation potential because ofsimple operation, higher recovery yield and no waste discharge.