Separation of salvianic acid A from the fermentation broth of engineered Escherichia coli using macroporous resins

Salvianic acid A (also known as danshensu) is a plant-derived polyphenolic acid, and has a variety of physiological and pharmacological activities. Our laboratory previously constructed an unprecedented artificial biosynthetic pathway in Escherichia coli and established the fermentation process to produce salvianic acid A. Here, we developed an efficient method for separating salvianic acid A from the fermentation broth of engineered Escherichia coli by macroporous resins. Among ten tested macroporous resins, the static and dynamic adsorption/desorption experiments demonstrated that X5 resin was the best to separate salvianic acid A from fermentation broth. Other parameters during static and dynamic procedures were also investigated. Under the optimum separation conditions, the average adsorption capacity of SAA were 10.66 +/- 0.54 mg/g dry resin and the desorption ratio was 85.6 +/- 4.1%. The purity and recovery yield of salvianic acid A in the final dry product were 90.2 +/- 1.5 and 81.5 +/- 2.3%, respectively. The results show that adsorption separation with macroporous resin X5 was an efficient method to prepare salvianic acid A from fermentation broth. This work will benefit the development and application of plant-derived salvianic acid A and its derivatives.