RESEARCH ARTICLE
Microrespirometric Validation of a Two-stage Process for Polyhydroxyalkanoates Production from Peanut Oil and Propionate with Cupriavidus necator
Irazú Pérez-Camacho1, Norberto Chavarría-Hernández1, Ma del Rocío López-Cuellar1, Claudia Guerrero-Barajas2, Alberto Ordaz3, *
Article Information
Identifiers and Pagination:
Year: 2024Volume: 18
E-location ID: e18741231301420
Publisher ID: e18741231301420
DOI: 10.2174/0118741231301420240306092952
Article History:
Received Date: 30/12/2023Revision Received Date: 21/02/2024
Acceptance Date: 28/02/2024
Electronic publication date: 02/04/2024
Collection year: 2024
open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: https://creativecommons.org/licenses/by/4.0/legalcode. This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Abstract
Introduction
Poly(3-hydroxyalkanoates) (PHA) is a biodegradable polyester synthesized by various bacteria, including Cupriavidus necator. The composition of PHA is influenced by the type of microorganism, cultivation conditions, and carbon substrate. The selection of a carbon source is critical for PHA production, significantly impacting process costs. Therefore, the common goal is scalability, with the design and optimization of PHA production relying on experimental determination of constitutive parameters.
Methods
In this work, a two-stage process for PHA production was conducted in shaking flasks functioning as mini reactors with the bacteria Cupriavidus necator. During the first stage, fructose was used as the sole carbon source. Once fructose was exhausted, a second stage commenced with a new carbon source, either peanut oil or propionate, to enhance PHA production. Ex-situ pulse respirometry approach was employed during the two-stage process to follow the kinetics of substrate consumption.
Results
The results indicated that the use of peanut oil would be advantageous over propionate, resulting in 12.2% more biomass and 13.9% more PHA.
Conclusion
Additionally, the growth rate was 88.9% higher with peanut oil. The characterization by pulse respirometry applied in microreactors, i.e., micro respirometry, allowed for the performance of up to 216 biological experiments to determine four important kinetic and stoichiometric parameters, namely maximum oxygen uptake (rO2max), substrate affinity constant (KS), growth yield (YX/S), and substrate oxidation yield (YO2/S). The values of these parameters indicated that peanut oil would be the best carbon source to promote PHA production during the second stage. The implementation of the microrespirometry technique during the screening of carbon sources for PHA production provided reliable information within a short period and with significantly less experimental effort.
