Release and Purification of Poly(3-hydroxybutyrate) P(3HB) via the Combined Use of an Autolytic Strain of Azotobacter vinelandii OP-PhbP3+ and Non-Halogenated Solvents
Year: 2025
Type: article
Abstract: P(3HB) is a biodegradable and biocompatible polymer, which can replace petroleum-derived plastics. Previous studies have shown that Azotobacter vinelandii strain OP-PhbP3+, which overexpresses the phasin protein PhbP3, produces high concentrations of P(3HB) and undergoes early autolysis, facilitating polymer release. The aim of the present study was to evaluate the performance of this strain for P(3HB) production in 3 L bioreactors and assess the feasibility of a simplified recovery process. After 36 h of cultivation, rapid cell lysis was observed, resulting in a ~50% decrease in the protein content of the cell dry weight, without reducing P(3HB) concentration, which reached 4.6 g L−1. Flow cytometry analysis revealed significant morphological changes during cultivation, which was consistent with the strain’s lytic behavior. The biomass recovered at 36 h was washed with SDS, obtaining a yield of 92.5% (respect to P(3HB) initial) and a purity of 97.6%. An alternative extraction procedure using the non-halogenated solvent cyclohexanone (CYC) resulted in an even higher yield of 97.8% with a purity of 99.3% of P(3HB). Notably, the weight average molecular weight of the polymer remained stable at 8000 kDa during the entire process. Overall, the combination of PhbP3 over-expression and environmentally friendly solvents, such as CYC, enabled efficient P(3HB) production with high yield and purity while preserving polymer quality.
Source: Fermentation
Authors: Joshua Valencia, Daniel Segura, Claudia Aguirre-Zapata, Enrique Galindo, Carlos Peña
Institution: Universidad Nacional Autónoma de México
Language: English
Subfield: Biomaterials
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,534
OpenAlex ID: W4414769023