Optimization of nitrogen feeding strategies for improving polyhydroxybutyrate production from biogas by Methylocystis parvus str. OBBP in a stirred tank reactor

Yadira Rodríguez; Silvia García; Rebeca Pérez; Raquel Lebrero; Raúl Muñoz

doi:10.1016/j.chemosphere.2022.134443

Optimization of nitrogen feeding strategies for improving polyhydroxybutyrate production from biogas by Methylocystis parvus str. OBBP in a stirred tank reactor

Chemosphere. 2022 Jul:299:134443. doi: 10.1016/j.chemosphere.2022.134443. Epub 2022 Mar 29.

Authors

Yadira Rodríguez¹, Silvia García², Rebeca Pérez³, Raquel Lebrero⁴, Raúl Muñoz⁵

Affiliations

¹ Department of Chemical Engineering and Environmental Technology, School of Industrial Engineering, University of Valladolid, Dr. Mergelina, s/n, 47011, Valladolid, Spain; Institute of Sustainable Processes, Dr. Mergelina, s/n, 47011, Valladolid, Spain. Electronic address: yadira.rodriguez@uva.es.
² Department of Chemical Engineering and Environmental Technology, School of Industrial Engineering, University of Valladolid, Dr. Mergelina, s/n, 47011, Valladolid, Spain; Institute of Sustainable Processes, Dr. Mergelina, s/n, 47011, Valladolid, Spain. Electronic address: silviamaria.garcia@alumnos.uva.es.
³ Department of Chemical Engineering and Environmental Technology, School of Industrial Engineering, University of Valladolid, Dr. Mergelina, s/n, 47011, Valladolid, Spain; Institute of Sustainable Processes, Dr. Mergelina, s/n, 47011, Valladolid, Spain. Electronic address: rebeca.perez@iq.uva.es.
⁴ Department of Chemical Engineering and Environmental Technology, School of Industrial Engineering, University of Valladolid, Dr. Mergelina, s/n, 47011, Valladolid, Spain; Institute of Sustainable Processes, Dr. Mergelina, s/n, 47011, Valladolid, Spain. Electronic address: raquel.lebrero@iq.uva.es.
⁵ Department of Chemical Engineering and Environmental Technology, School of Industrial Engineering, University of Valladolid, Dr. Mergelina, s/n, 47011, Valladolid, Spain; Institute of Sustainable Processes, Dr. Mergelina, s/n, 47011, Valladolid, Spain. Electronic address: mutora@iq.uva.es.

PMID: 35364084
DOI: 10.1016/j.chemosphere.2022.134443

Abstract

The design of efficient cultivation strategies to produce bioplastics from biogas is crucial for the implementation of this biorefinery process. In this work, biogas-based polyhydroxybutyrate (PHB) production and CH₄ biodegradation performance was investigated for the first time in a stirred tank bioreactor inoculated with Methylocystis parvus str. OBBP. Decreasing nitrogen loading rates in continuous mode and alternating feast:famine regimes of 24 h-cycles, and alternating feast:famine regimes of 24 h:24 h and 24 h:48 h were tested. Continuous N feeding did not support an effective PHB production despite the occurrence of nitrogen limiting conditions. Feast-famine cycles of 24 h:24 h (with 50% stoichiometric nitrogen supply) supported the maximum PHB production (20 g-PHB m^-3 d^-1) without compromising the CH₄-elimination capacity (25 g m^-3 h^-1) of the system. Feast:famine ratios ≤1:2 entailed the deterioration of process performance at stoichiometric nitrogen inputs ≤60%.

Keywords: Bioplastics; Biorefinery concept; Feeding regime; Methane oxidation; Methanotrophic bacteria; Polyhydroxyalkanoate production.

MeSH terms

Biofuels*
Bioreactors
Methane / metabolism
Methylocystaceae* / metabolism
Nitrogen / metabolism

Substances

Biofuels
Nitrogen
Methane

Supplementary concepts

Methylocystis parvus