Metabolic evolution of <i>Escherichia coli </i>strains that produce organic acids

摘要

This invention relates to the metabolic evolution of a microbial organism previously optimized for producing an organic acid in commercially significant quantities under fermentative conditions using a hexose sugar as sole source of carbon in a minimal mineral medium. As a result of this metabolic evolution, the microbial organism acquires the ability to use pentose sugars derived from cellulosic materials for its growth while retaining the original growth kinetics, the rate of organic acid production and the ability to use hexose sugars as a source of carbon. This invention also discloses the genetic change in the microorganism that confers the ability to use both the hexose and pentose sugars simultaneously in the production of commercially significant quantities of organic acids.

主权项

1. An isolated Escherichia coli bacterial cell comprising a mutation in galactose symporter (galP) gene, wherein said bacterial cell comprises at least one mutation that decreases the activity of PEP-dependent phosphotransferase system and utilizes C5 and C6 sugars simultaneously to produce an industrially useful chemical and said mutation in GalP gene comprises replacement of a glycine residue at position 297 with aspartic acid residue.