title: Shikimic acid production by a modified strain of E. coli (W3110.shik1) under phosphate-limited and carbon-limited conditions.
abstract: Shikimic acid is one of several industrially interesting chiral starting materials formed in the aromatic amino acid pathway of plants and microorganisms. In this study, the physiology of a shikimic acid producing strain of Escherichia coli (derived from W3110) deleted in aroL (shikimic acid kinase II gene), was compared to that of a corresponding control strain (W3110) under carbon- and phosphate-limited conditions. For the shikimic acid producing strain (referred to as W3110.shik1), phosphate limitation resulted in a higher yield of shikimic acid (0.059 +/- 0.012 vs. 0.024 +/- 0.005 c-mol/c-mol) and a lower yield of by-products from the shikimate pathway, when compared to carbon-limited condition. The yield of the by-product 3-dehydroshikimic acid (DHS) decreased from 0.076 +/- 0.028 to 0.022 +/- 0.001 c-mol/c-mol. Several other by-products were only detected under carbon-limited conditions. The latter group included 3-dehydroquinic acid (0.021 +/- 0.021 c-mol/c-mol), quinic acid (0.012 +/- 0.005 c-mol/c-mol), and gallic acid (0.002 +/- 0.001 c-mol/c-mol). For both strains, more acetate was produced under phosphate than the carbon-limited case. Considerable cell lysis was found for both strains but was higher for W3110.shik1, and increased for both strains under phosphate limitation. The advantages of the latter condition in terms of an increased shikimic acid yield was thus counteracted by an increased cell lysis, which may make downstream processing more difficult.
authors.affiliation: Department of Chemical Engineering, Lund University, P.O. Box 124, 221 00 Lund, Sweden. Louise.Johansson@chemeng.lth.se
authors.forename: Louise
authors.initials: L
authors.lastname: Johansson
authors.forename: Anna
authors.initials: A
authors.lastname: Lindskog
authors.forename: Gustav
authors.initials: G
authors.lastname: Silfversparre
authors.forename: Christian
authors.initials: C
authors.lastname: Cimander
authors.forename: Kristian Fog
authors.initials: KF
authors.lastname: Nielsen
authors.forename: Gunnar
authors.initials: G
authors.lastname: Lidén
mesh_terms: D019149:Bioreactors / Q000382:microbiology*; D002244:Carbon / Q000378:metabolism*; D018929:Cell Culture Techniques / Q000379:methods*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D024861:Genetic Enhancement / Q000379:methods; D010710:Phosphates / Q000378:metabolism*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics / Q000378:metabolism*; D015202:Protein Engineering / Q000379:methods; D012765:Shikimic Acid / Q000378:metabolism*; D013045:Species Specificity
chemical_list: D010710:Phosphates; D012765:Shikimic Acid; D002244:Carbon; D017853:Phosphotransferases (Alcohol Group Acceptor); C022642:shikimate kinase