Porphyrin derivatives from a recombinant Escherichia coli grown on chemically defined medium

J Microbiol Biotechnol. 2012 Dec;22(12):1653-8. doi: 10.4014/jmb.1208.08054.

Abstract

We have reported previously that a recombinant Escherichia coli co-expresses aminolevulinic acid (ALA) synthase, an NADP-dependent malic enzyme, and a dicarboxylate transporter-produced heme, an iron-chelated porphyrin, in a succinate-containing complex medium. To develop an industrially plausible process, a chemically defined medium was formulated based on M9 minimal medium. Heme synthesis was enhanced by adding sodium bicarbonate, which strengthened the C4 metabolism required for the precursor metabolite, although a pH change discouraged cell growth. Increasing the medium pH buffering capacity (100mM phosphate buffer) and adding sodium bicarbonate enabled the recombinant E. coli to produce heme at rates 60% greater than those in M9 minimal medium. Adding growth factors (1 mg/l thiamin, 0.01 mg/l biotin, 5 mg/l nicotinic acid, 1 mg/l pantothenic acid, and 1.4 mg/l cobalamin) also induced positive heme production effects at levels twice of heme production in M9-based medium. Porphyrin derivatives and heme were found in the chemically defined medium, and their presence was confirmed by liquid chromatography/mass spectroscopy (LC/MS). The formulated medium allowed for the production of 0.6 microM heme, 29 microM ALA, 0.07 microM coproporphyrin I, 0.21 microM coproporphyrin III, and 0.23 microM uroporphyrin in a 3 L pH-controlled culture.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacteriological Techniques / methods*
  • Bioreactors / microbiology*
  • Chromatography, Liquid
  • Culture Media*
  • Escherichia coli / genetics
  • Escherichia coli / growth & development*
  • Escherichia coli / metabolism*
  • Hydrogen-Ion Concentration
  • Mass Spectrometry
  • Metabolic Networks and Pathways
  • Phosphates / chemistry
  • Porphyrins / analysis
  • Porphyrins / biosynthesis*
  • Porphyrins / chemistry
  • Porphyrins / metabolism
  • Sodium Bicarbonate / chemistry
  • Vitamins

Substances

  • Culture Media
  • Phosphates
  • Porphyrins
  • Vitamins
  • Sodium Bicarbonate