Increased riboflavin production by knockout of 6-phosphofructokinase I and blocking the Entner-Doudoroff pathway in Escherichia coli.

Abstract

To construct an Escherichia coli strain capable of producing riboflavin with high titer and yield. A low copy number plasmid pLS01 containing a riboflavin operon under the control of a constitutive promoter was constructed and introduced into Escherichia coli MG1655. Subsequently, the pfkA, edd and ead genes were disrupted, and the resulting strain LS02T produced 667mg riboflavin/l in MSY medium supplied with 10g glucose/l in flask cultivation. In a fed-batch process, riboflavin production of the strain reached 10.4g/l with a yield of 56.8mg riboflavin/g glucose. To our knowledge, this is the first report of engineered E. coli strains that can produce more than 10g riboflavin/l in fed-batch cultivation, indicating that E. coli has potential for riboflavin production.