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Crop Biotech Update

Genetic Modification of Escherichia coli for Propionate Production

April 19, 2017

Propionate is used as an important preservative and important chemical intermediate for the synthesis of cellulose fibers, herbicides, perfumes, and pharmaceuticals. Biosynthetic propionate has mainly been produced by Propionibacterium, which has various limitations for industrial application.

Jing Li led a group of scientists from the Chinese Academy of Sciences and engineered Escherichia coli, combining a reduced TCA cycle with the native sleeping beauty mutase (Sbm) cycle to construct a fermentation pathway for anaerobic propionate production. The team overexpressed the Sbm operon in E. coli MG1655, yielding 0.24 g/L of propionate.

Genetic modification was also done to convert mixed fermentation products to succinate to increase precursors, thus, slightly increasing yield. Different types of promoters were also evaluated to maximize the Sbm operon. The constitutive promoter Pbba led to the highest titer of 2.34 g/L. Methylmalonyl CoA mutase from Methylobacterium extorquens AM1 was also added to strain T110 (pbba-Sbm) to enhance this process.

This study lays the groundwork for industrial propionate production using E. coli.

For more on this study, read the article in BMC Biotechnology.