Production of Poly-3-Hydroxybutyrate (P3HB) with Ultra-High Molecular Weight (UHMW) by Mutant Strains of Azotobacter vinelandii Under Microaerophilic Conditions

Elsa Gómez-Hernández, Holjes Salgado-Lugo, Daniel Segura, Andrés García, ALVARO ENRIQUE DIAZ BARRERA, Carlos Peña

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Poly-3-hydroxybutyrate (P3HB) is a biopolymer, which presents characteristics similar to those of plastics derived from the petrochemical industry. The thermomechanical properties and biodegradability of P3HB are influenced by its molecular weight (MW). The aim of the present study was to evaluate the changes of the molecular weight of P3HB as a function of oxygen transfer rate (OTR) in the cultures using two strains of Azotobacter vinelandii, a wild-type strain OP, and PhbZ1 mutant with a P3HB depolymerase inactivated. Both strains were grown in a bioreactor under different OTR conditions. An inverse relationship was found between the average molecular weight of P3HB and the OTRmax, obtaining a polymer with a maximal MW (8000–10,000 kDa) from the cultures developed at OTRmax of 5 mmol L−1 h−1 using both strains, with respect to the cultures conducted at 8 and 11 mmol L−1 h−1, which produced a P3HB between 4000 and 5000 kDa. The increase in MW of P3HB was related to the activity of enzymes involved in the synthesis and depolymerization. Overall, our results show that it is possible to modulate the average molecular weight of P3HB by manipulating oxygen transfer conditions with both strains (OP and PhbZ1 mutant) of A. vinelandii.

Original languageEnglish
Pages (from-to)79-95
Number of pages17
JournalApplied Biochemistry and Biotechnology
Volume193
Issue number1
DOIs
StatePublished - Jan 2021
Externally publishedYes

Keywords

  • Acetoacetyl-CoA reductase
  • Azotobacter vinelandii
  • Biodegradability
  • Biopolymer
  • P3HB synthase
  • Poly-3-hydroxybutyrate
  • β-ketothiolase

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