Engineering a branch of the UDP‐precursor biosynthesis pathway enhances the production of capsular polysaccharide in Escherichia coli O5:K4:H4. Issue 8 (24th July 2015)

• Record Type: Journal Article
• Authors: Cimini, Donatella; Carlino, Elisabetta; Giovane, Alfonso; Argenzio, Ottavia; Dello Iacono, Ileana; De Rosa, Mario; Schiraldi, Chiara
• Is Part Of: Biotechnology journal. Volume 10:Issue 8(2015:Aug.)
• Page Start: 1307
• Page End: 1315
• Publication Date: 2015-07-24
• Subjects: Biotechnology -- Periodicals; 660.605
• DOI: 10.1002/biot.201400602
• Languages: English
• ISSNs: 1860-6768

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p> <italic>Escherichia coli</italic> K4 produces a capsule with a chemical structure that resembles chondroitin, a molecule with established chondro protective properties. The endogenous genes <italic>pgm</italic> and <italic>galU</italic> are involved in the biosynthesis of UDP‐glucose which is a critical intermediate in carbohydrate metabolism and biochemical precursor of UDP‐glucuronic acid. Together with UDP‐<italic>N</italic>‐acetylgalactosamine, UDP‐glucuronic acid is used as sugar donor for capsule biosynthesis. The aim of the study was to evaluate how a change in the pathways leading to UDP‐glucuronic acid biosynthesis affected capsular polysaccharide production. One additional copy of <italic>pgm</italic> and <italic>galU</italic> was introduced in <italic>E. coli</italic> K4 and in the previously described recombinant strain EcK4r3. A microbioreactor was used to analyse strain performance with parallel batch experiments, demonstrating increased polysaccharide concentrations and providing data that are comparable to those obtained in larger fermenters. Further experiments on a glutamine enriched medium showed an additional 45% increase of capsule production, maybe indicating the need to balance both branches leading to polymer biosynthesis in order to maximize yields. In the effort towards the establishment of a feasible bio‐chondroitin production process this study provides information on how the availability of sugar precursors impacts polysaccharide biosynthesis in <italic>E. coli</italic> K4, a complex unexplored aspect of a multifaceted process.</p> </abstract>