The purity of sialic acid, which is hydrolyzed from polysialic acid broth produced by Escherichia coli, was low and required to be further purified for commercial application.

• 摘要大肠杆菌发酵得到聚唾液酸，经酸水解后得到的唾液酸单体纯度较低，需进一步分离和纯化。