Wastewater treatment and biosynthesis from Pseudomonas citronellolis in microbial electrochemical technologies: Part A
Wastewater treatment and biosynthesis from Pseudomonas citronellolis in microbial electrochemical technologies: Part A
Despite the potential of microbial electrochemical technologies (METs) in wastewater treatment, their performance under discontinuous or low-maintenance conditions remains underexplored. In this study, we evaluated
the electro-bioremediation potential of Pseudomonas citronellolis 620C in dual-chamber microbial fuel cells
(MFCs) treating oily wastewater rich in complex compounds (>43,000 mg/L Chemical Oxygen Demand, COD).
During a 28-day fed-batch operation (Cycle 1), including a 7-day intentional feed interruption to simulate realworld constraints, the system achieved >92 % COD removal, 94.8 % total petroleum hydrocarbon (TPH)
removal, 98.1 % naphthalene degradation, and 74.5 % fatty acid reduction, while sustaining power output.
Physicochemical analyses confirmed the biosynthesis of added-value metabolites such as polyhydroxyalkanoate (PHA) monomers, a lipopeptide biosurfactant (BSF), and the redox mediator pyocyanin that
contributed to electro-assisted oily wastewater degradation. Electricity generation during starvation was likely
supported by intracellular PHA consumption, highlighting their role as energy reserves, along with residual oily
wastewater oxidation due to the high initial COD. Notably, the BSF composition under MFC conditions differed
from that produced aerobically.
Over a four-month starvation period, power output remained relatively stable (0.006 mW). Upon re-feeding
(Cycle 2) under identical conditions as Cycle 1, electrochemical activity and biodegradation performance
were fully restored, achieving 95.2 % COD removal and a peak power output of 0.01 mW. These findings
demonstrate that P. citronellolis 620C is a remarkably resilient platform for oily wastewater remediation with
concomitant bioproduct synthesis under discontinuous MET operation, effectively transitioning between active,
growth-supporting metabolism and survival-oriented states
Lipopeptide biosurfactant, Long-term starvation recovery, Oily wastewater treatment, Polyhydroxyalkanoates, Resilience
Varnava, Constantina K.
62233e63-5d71-4c7b-8ae4-54e9152d5273
Ieropoulos, Ioannis
6c580270-3e08-430a-9f49-7fbe869daf13
Leontidis, Epameinondas
603bbc19-b099-4d6b-b542-5ab0a6aecdfc
Tsipa, Argyro
b642bb29-53c9-4cf4-8c0d-139584b8a5ab
25 December 2025
Varnava, Constantina K.
62233e63-5d71-4c7b-8ae4-54e9152d5273
Ieropoulos, Ioannis
6c580270-3e08-430a-9f49-7fbe869daf13
Leontidis, Epameinondas
603bbc19-b099-4d6b-b542-5ab0a6aecdfc
Tsipa, Argyro
b642bb29-53c9-4cf4-8c0d-139584b8a5ab
Varnava, Constantina K., Ieropoulos, Ioannis, Leontidis, Epameinondas and Tsipa, Argyro
(2025)
Wastewater treatment and biosynthesis from Pseudomonas citronellolis in microbial electrochemical technologies: Part A.
Sustainable Energy Technologies and Assessments, 84, [104720].
(doi:10.1016/j.seta.2025.104720).
Abstract
Despite the potential of microbial electrochemical technologies (METs) in wastewater treatment, their performance under discontinuous or low-maintenance conditions remains underexplored. In this study, we evaluated
the electro-bioremediation potential of Pseudomonas citronellolis 620C in dual-chamber microbial fuel cells
(MFCs) treating oily wastewater rich in complex compounds (>43,000 mg/L Chemical Oxygen Demand, COD).
During a 28-day fed-batch operation (Cycle 1), including a 7-day intentional feed interruption to simulate realworld constraints, the system achieved >92 % COD removal, 94.8 % total petroleum hydrocarbon (TPH)
removal, 98.1 % naphthalene degradation, and 74.5 % fatty acid reduction, while sustaining power output.
Physicochemical analyses confirmed the biosynthesis of added-value metabolites such as polyhydroxyalkanoate (PHA) monomers, a lipopeptide biosurfactant (BSF), and the redox mediator pyocyanin that
contributed to electro-assisted oily wastewater degradation. Electricity generation during starvation was likely
supported by intracellular PHA consumption, highlighting their role as energy reserves, along with residual oily
wastewater oxidation due to the high initial COD. Notably, the BSF composition under MFC conditions differed
from that produced aerobically.
Over a four-month starvation period, power output remained relatively stable (0.006 mW). Upon re-feeding
(Cycle 2) under identical conditions as Cycle 1, electrochemical activity and biodegradation performance
were fully restored, achieving 95.2 % COD removal and a peak power output of 0.01 mW. These findings
demonstrate that P. citronellolis 620C is a remarkably resilient platform for oily wastewater remediation with
concomitant bioproduct synthesis under discontinuous MET operation, effectively transitioning between active,
growth-supporting metabolism and survival-oriented states
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Accepted/In Press date: 22 November 2025
e-pub ahead of print date: 30 November 2025
Published date: 25 December 2025
Additional Information:
Publisher Copyright:
© 2025 Elsevier Ltd.
Keywords:
Lipopeptide biosurfactant, Long-term starvation recovery, Oily wastewater treatment, Polyhydroxyalkanoates, Resilience
Identifiers
Local EPrints ID: 507458
URI: http://eprints.soton.ac.uk/id/eprint/507458
ISSN: 2213-1388
PURE UUID: 3763e775-ad26-4c32-a409-f147aa630fa3
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Date deposited: 09 Dec 2025 17:54
Last modified: 13 Dec 2025 02:59
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Contributors
Author:
Constantina K. Varnava
Author:
Epameinondas Leontidis
Author:
Argyro Tsipa
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