Poly(3-hydroxybutyrate) synthesis from glycerol by a recombinant Escherichia coli arcA mutant in fed-batch microaerobic cultures

Pablo Ivan Nikel, M. Julia Pettinari, Miguel A. Galvagno, Beatriz S. Méndez

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Poly(3-hydroxybutyrate) (PHB) synthesis was analyzed under microaerobic conditions in a recombinant Escherichia coli arcA mutant using glycerol as the main carbon source. The effect of several additives was assessed in a semi-synthetic medium by the 'one-factor-at-a-time' technique. Casein amino acids (CAS) concentration was an important factor influencing both growth and PHB accumulation. Three factors exerting a statistically significant influence on PHB synthesis were selected by using a Plackett-Burman screening design [glycerol, CAS, and initial cell dry weight (CDW) concentrations] and then optimized through a Box-Wilson design. Under such optimized conditions (22.02 g l-1 glycerol, 1.78 g l-1 CAS, and 1.83 g l-1 inoculum) microaerobic batch cultures gave rise to 8.37 g l-1 CDW and 3.52 g l-1 PHB in 48 h (PHB content of 42%) in a benchtop bioreactor. Further improvements in microaerobic PHB accumulation were obtained in fed-batch cultures, in which glycerol was added to maintain its concentration above 5 g l-1. After 60 h, CDW and PHB concentration reached 21.17 and 10.81 g l-1, respectively, which results in a PHB content of 51%. Microaerobic fed-batch cultures allowed a 2.57-fold increase in volumetric productivity when compared with batch cultures.
Original languageEnglish
JournalApplied Microbiology and Biotechnology
Volume77
Issue number6
Pages (from-to)1337-1343
Number of pages7
ISSN0175-7598
DOIs
Publication statusPublished - 2008
Externally publishedYes

Keywords

  • Escherichia coli
  • arcA mutant
  • Fed-batch culture
  • Microaerobic cultivation
  • Poly(3-hydroxybutyrate)

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