Production of Polyhydroxybutyrate by Genetically Modified Pseudomonas sp. phDV1: A Comparative Study of Utilizing Wine Industry Waste as a Carbon Source

Athina Drakonaki; Eirini Mathioudaki; Ermis Dionysios Geladas; Eleni Konsolaki; Nikolaos Vitsaxakis; Nikos Chaniotakis; Hao Xie; Georgios Tsiotis

doi:10.3390/microorganisms11061592

Production of Polyhydroxybutyrate by Genetically Modified Pseudomonas sp. phDV1: A Comparative Study of Utilizing Wine Industry Waste as a Carbon Source

Microorganisms. 2023 Jun 15;11(6):1592. doi: 10.3390/microorganisms11061592.

Authors

Athina Drakonaki¹, Eirini Mathioudaki¹, Ermis Dionysios Geladas¹, Eleni Konsolaki¹, Nikolaos Vitsaxakis¹, Nikos Chaniotakis¹, Hao Xie², Georgios Tsiotis¹

Affiliations

¹ Department of Chemistry, University of Crete, GR-70013 Voutes, Greece.
² Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, D-60438 Frankfurt am Main, Germany.

Abstract

Pseudomonas sp. phDV1 is a polyhydroxyalkanoate (PHA) producer. The presence of the endogenous PHA depolymerase (phaZ) responsible for the degradation of the intracellular PHA is one of the main shortages in the bacterial production of PHA. Further, the production of PHA can be affected by the regulatory protein phaR, which is important in accumulating different PHA-associated proteins. PHA depolymerase phaZ and phaR knockout mutants of Pseudomonas sp. phDV1 were successfully constructed. We investigate the PHA production from 4.25 mM phenol and grape pomace of the mutants and the wild type. The production was screened by fluorescence microscopy, and the PHA production was quantified by HPLC chromatography. The PHA is composed of Polydroxybutyrate (PHB), as confirmed by ¹H-nuclear magnetic resonance analysis. The wildtype strain produces approximately 280 μg PHB after 48 h in grape pomace, while the phaZ knockout mutant produces 310 μg PHB after 72 h in the presence of phenol per gram of cells, respectively. The ability of the phaZ mutant to synthesize high levels of PHB in the presence of monocyclic aromatic compounds may open the possibility of reducing the costs of industrial PHB production.

Keywords: PHB; Pseudomonas sp. strain phDV1; phaR knockout; phaZ knockout; polyhydroxyalkanoates.

Grants and funding

This research has been co-financed by the European Regional Development Fund of the European Union and Greek National Funds through the Operational Program Competitiveness, Entrepreneurships, and Innovation, under the call RESEARCH-CREATE-INNOVATE (project code: T2EDK-00523).