Succinic acid (1,4-butanedioic acid, ) is important for the synthesis of some valuable chemical derivatives, which can be used in food and pharmaceutical products, solvents, biodegradable polymers, surfactants and detergents. Biological production of succinic acid has been investigated intensively due to its independence from petroleum, environmental benefit and CO2 sequestration during recent years. However, product inhibition during fermentation, complexity and the multistep of the downstream process and the high cost of bio-succinic acid limit the biotechnological production of succinic acid industrially. Besides, until now the purified succinic acid cannot fulfill the synthesis of poly (butylene succinate) (PBS).

Recently, Prof. XING Jianmin’s group in Institute of Process Engineering (IPE) developed a novel integrated process for biotechnological production of succinic acid which can be used for further PBS synthesis or chemical transformation. With this integrated system, product inhibition was alleviated by removing acids and replenishing fresh broth. High cell density maintain for a longer time from 75 to 130 h and succinic acid concentration increased from 53 to 73 g/L. In the developed separation process, succinic acid was crystallized at a recovery of 85–90%. The purity of the obtained succinic acid crystals reached 99.4% as found by HPLC and 1HNMR analysis. A crystallization experiment indicated that among by-products glucose had a negative effect on succinic acid crystallization. Poly (butylene succinate) (PBS) was synthesized using the purified succinic acid and 1H NMR analysis confirmed that the composition of the synthesized PBS is in agreement with that from petro-based succinic acid. The MW of the synthesized PBS reached up to 15,000 g/mol. The purity of succinic acid is good enough for PBS synthesis. So, this novel integrated process for biotechnological production of succinic acid might be adequate for industrial application.

The research was supported by the National High Technology Research and Development Program of China (863 Project, no. 2012AA101807, 2011AA02A203 and 2012AA022301). The results have been published on Bioresource Technology, Volume 156, March 2014, Pages 6–13