Monday, April 30, 2007

Optimization of succinic acid production by E.coli

Amarjeet Singh, Michael D Lynch, and Ryan T. Gill. Chemical & Biological Engineering, University of Colorado, 1111 Engineering Drive, Campus Box 424, Boulder, CO 80309

Succinic acid has been identified as an important platform chemical and is one of the primary focuses of bio-refining efforts.  Many recombinant strains have been constructed for the biochemical production of succinate from biomass.  All of the recombinant strains, however, suffer from poor growth properties. One such recombinant E.coli strain, capable of producing succinic acid, that suffers from poor growth properties is NZN111.

We are aiming to improve the productivity of succinic acid fermentation by NZN111 strain by optimizing bacterial metabolism. We are using plasmid library based overexpression technique of bacterial genes and knockout library based deletion strategy to optimize bacterial growth. We have identified a set of genes, whose expression need to be turned up, and a set of genes that need to be deleted, to improve the growth and productivity of succinate formation. Using a combination of deletion and over-expression of the identified genes, succinate productivity of > 4g/l/hr was achieved.