Engineering of Escherichia coli for high-level production of styrene from glucose

Abstract

In the past few decades, global styrene production has been increasing due to styrene’s diverse use as the main building-block for various industrial styrene-derived polymers. Conventionally, the industrial supply for styrene has solely relied on the chemical synthesis from ethylbenzene. As an alternative strategy, biosynthesis of styrene has been demonstrated in various models including E. coli. However, previous studies have mostly focused on the pathway construction itself, or optimizing the culture conditions in order to deal with the end-product’s toxicity, leading to a relatively poor productivity. This work aimed to increase the production of styrene towards an applicable level in industry. In order to provide maximum flux towards the synthesis pathway, high-trans-cinnamic acid producer, obtained based on metabolic engineering, was applied. Also, production system was optimized by regulating enzyme expression levels an optimizing the culture media. From this, 1.9 g/L of styrene was produced from flask cultures. Finally, fed-batch cultures performed and optimized in order to further enhance the production titer. As a result, a maximum titer of 5.26 g/L was achieved by fed-batch cultures.