The Escherichia coli CitT transporter can be used as a succinate exporter for succinate production

Abstract

Escherichia coli strain, whose gene is one of the subunits of succinate dehydrogenase (sdhA), and gene of the transcriptional repressor of isocitrate lyase (iclR) were disrupted, accumulated 6.6 times as much intracellular succinate as the wild-type MG1655 strain in aerobic growth, but succinate was not found in the culture medium. E. coli citT gene that encodes a citrate transporter was cloned under the control of the lacI promoter in pBR322-based plasmid and the above strain was transformed. This transformant, grown under aerobic condition in M9-tryptone medium with citrate, accumulated succinate in the medium while no succinate was found in the medium without citrate. CitT was active as a succinate transporter for 168 h by changing the culture medium or for 24 h in fed-batch culture. This study suggests that the CitT transporter functions as a succinate exporter in E. coli for succinate production in the presence of citrate.

Construction of an Escherichia coli Strain Capable of Utilizing Steamed Rice as the Sole Carbon and Energy Source by Extracellular Expression of Amylase and Its Use for the Production of Putrescine

“…Escherichia coli has been used to produce a variety of useful substances. Recently, attempts have been made to make E. coli produce chemicals that are conventionally produced from petroleum, such as cadaverine [1,2], succinate [3,4], butanol [5][6][7], adipic acid [8,9], propanol [10,11], ethanol [12][13][14] and methane [15]. E. coli requires some carbon sources, such as sugars, to grow.…”