Effect of periplasmic nitrate reductase on diauxic lag of Paracoccus pantotrophus

Biotechnol Prog. Jul-Aug 2009;25(4):973-9. doi: 10.1002/btpr.176.


Paracoccus pantotrophus expresses two nitrate reductases-membrane bound nitrate reductase (Nar) and periplasmic nitrate reductase (Nap). In growth experiments with two denitrifying species (Paracoccus pantotrophus and Alcaligenes eutrophus) that have both Nap and Nar and two species (Pseudomonas denitrificans and Pseudomonas fluorescens) with Nar only, it was found that diauxic lag is shorter for bacteria that express Nap. In P. pantotrophus, napEDABC encodes the periplasmic nitrate reductase. To analyze the effect of Nap on diauxic lag, the nap operon was deleted from P. pantotrophus. The growth experiments with nap(-) mutant resulted in increased diauxic lag when switched from aerobic to anoxic respiration, suggesting Nap is responsible for shorter lags and helps in adaptation to anoxic metabolism after transition from aerobic conditions.

MeSH terms

  • Aerobiosis
  • Anaerobiosis
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Nitrate Reductase / genetics
  • Nitrate Reductase / metabolism*
  • Paracoccus pantotrophus / enzymology*
  • Paracoccus pantotrophus / genetics
  • Paracoccus pantotrophus / growth & development*
  • Periplasmic Proteins / genetics
  • Periplasmic Proteins / metabolism*


  • Bacterial Proteins
  • Periplasmic Proteins
  • Nitrate Reductase