Oxygen sensitive global regulator, Anr, is involved in biosynthesis of poly-3-hydroxybutyrate (PHB) in Pseudomonas extremaustralis

TRIBELLI, P.M.; MÉNDEZ, B.S.; LÓPEZ, N.I.

JOURNAL OF MOLECULAR MICROBIOLOGY AND BIOTECHNOLOGY

KARGER

Lugar: Londres; Año: 2010 vol. 19 p. 180 - 188

1464-1801

We analyzed the influence of the redox global regulator Anron the accumulation of poly(3-hydroxybutyrate) (PHB) inPseudomonas extremaustralis . Anr regulates a set of genes inthe aerobic-anaerobic transition including genes involved innitrate reduction and arginine fermentation. An anr mutantwas constructed using PCR-based strategies. The wild-typestrain was able to grow in both microaerobic and anaerobicconditions using nitrate as the terminal electron acceptorwhile the mutant strain was unable to grow under anaerobicconditions. In bioreactor cultures, PHB content in the wildtypestrain was higher in microaerobic and anaerobic culturescompared with highly aerated cultures. The mutantstrain showed decreased PHB levels in both aerobic and microaerobicconditions compared with the wild-type strain.Inactivation of anr led to decreased expression of phaC andphaR genes as demonstrated in real-time RT-PCR experiments.Associated with the PHB gene region, two putativebinding sites for Anr were found that, in line with the phenotypeobserved in bioreactor cultures, suggest a role of thisregulator in PHB biosynthesis.