Argyro Tsipa

Environmental challenges continue to intensify globally, highlighting the urgent need to foster Environmental Citizenship (ECn) among younger generations, particularly within higher education. Despite increasing policy emphasis on sustainability education, limited cross-national evidence exists on how students translate environmental awareness into action. This study employs a quantitative, comparative design using survey data from 2,013 higher education students across seven countries (Croatia, Cyprus, France, Italy, Lebanon, Spain, and Sweden). Exploratory and confirmatory factor analyses were conducted to validate a reduced Environmental Citizenship Questionnaire (rECQ) and examine students’ motivations, competences, intentions, and behaviors. Results reveal a consistent pattern across countries: while students demonstrate high levels of environmental values (M = 3.54) and attitudes (M = 3.49), as well as strong intrinsic and extrinsic motivation (M ≈ 4.7), their engagement in past environmental actions remains notably low (M = 1.77). Competences and intentions are significantly higher than actual behaviors ( p <.001), indicating a substantial intention–action gap. Correlation analyses further show weak links between past actions and other ECn dimensions, while attitudes, values, and intentions are moderately to strongly interrelated. Cross-country differences highlight stronger motivation and engagement in Cyprus and Croatia, while contextual factors such as family influence play a key role in Lebanon. Overall, the validated 9-factor rECQ demonstrates robust cross-cultural applicability. The findings emphasize the need for higher education institutions to move beyond awareness-based approaches by integrating experiential, action-oriented learning and motivational support mechanisms to effectively translate environmental commitment into sustained behavioral engagement.

Oil bioremediation may be achievable via Pseudomonas spp. leading to low-cost biosurfactant (BSF) production, but the environmental impact is unclear. Here, we studied P. aeruginosa PA14 and PAO1; P. putida mt-2 and F1; and P. citronellolis 620C, P3B5, and SJTE-3, for their ability to degrade oily wastewater (OW), produce BSFs, and impact the model insect, Drosophila melanogaster . Biodegradation was > 86% by day 1 and > 93% by day 7, while BSF production was > 200 mg/L by day 1 and > 400 mg/L by day 7 for all strains. P. aeruginosa PAO1 and PA14 produce rhamnolipids and glycolipopeptides, respectively. P. putida mt-2 and F1 formed glycolipopeptides and glycolipids, respectively . P. citronellolis P3B5 and SJTE-3 yielded glycolipids, whereas 620C produced lipopeptides. Strikingly, Drosophila was mostly attracted to food contaminated with any of the P. aeruginosa strains or P. putida mt-2, which were the most virulent. To the contrary, Drosophila was repelled from food containing the low in virulence P. putida F1 or any of the P. citronellolis strains. All strains exhibited high ability to colonize Drosophila and disperse from fly to fly, but the colonization and contagion extend by P. aeruginosa strains were slightly higher. Moreover, the virulence of Pseudomonas spp. aligned with the toxicity of their BSFs. BSFs produced by P. aeruginosa were the most toxic, followed by P. putida and P. citronellolis , indicating a correlation between BSF toxicity and microbial origin. We concluded that P. citronellolis strains and their BSFs are relatively innocuous to the fly populations, yet highly potent in biodegrading OW. Key points: • >93% biodegradation of oily wastewater by all Pseudomonas spp. strains by day 7 • The virulence of Pseudomonas spp. aligns with the toxicity of their BSFs • P. citronellolis strains and their BSFs are more innocuous to Drosophila than those of P. putida and P. aeruginosa

Electro-bioremediation of wastewater is a novel, nature-based solution towards clean water, based on microbial electrochemical technologies (METs). Electro-bioremediation technologies for wastewater treatment, except enhanced bioremediation results and renewable energy generation, offer an unlocked opportunity for harvesting by-products and using them in other applications. This concept contributes to circularity, sustainability, and environmental compatibility, mitigating the impact of climate change. In addition, wastewater valorization and, thus, water resilience are possible thereby leading to protection of water resources. Compounds and metabolites naturally synthesized by the microorganisms involved in the wastewater electro-assisted biodegradation, can result in the enhancement of both extracellular electron transfer (EET) and bioremediation. Such microbial products are added-value, natural, non-toxic and biodegradable such as biosurfactants (BSFs) and polyhydroxyalkanoates (PHAs). In this chapter, the effect of the presence of BSFs and PHAs in MET during electro-bioremediation, as well as when fed with conventional substrates, are exhaustively evaluated. The significance of BSFs even when they are added exogenously is also examined. The major categories of by-products biosynthesis including organic acids, biopolymers, recovered heavy metals and phenazines such as pyocyanin during electro-bioremediation processes are also discussed. Consequently, a future direction in wastewater electro-bioremediation is proposed. Graphical Abstract

In the present study, the potential of Pseudomonas citronellolis 620C strain was evaluated, for the first time, to generate electricity in a standard, double chamber microbial fuel cell (MFC), with oily wastewater (OW) being the fuel at 43.625 mg/L initial chemical oxygen demand (COD). Both electrochemical and physicochemical results suggested that this P. citronellolis strain utilized efficiently the OW substrate and generated electricity in the MFC setup reaching 0.05 mW/m² maximum power. COD removal was remarkable reaching 83.6 ± 0.1%, while qualitative and quantitative gas chromatography/mass spectrometry (GC/MS) analysis of the OW total petroleum and polycyclic aromatic hydrocarbons, and fatty acids revealed high degradation capacity. It was also determined that P. citronellolis 620C produced pyocyanin as electron shuttle in the anodic MFC chamber. To the authors’ best knowledge, this is the first study showing (phenazine-based) pyocyanin production from a species other than P. aeruginosa and, also, the first time that P. citronellolis 620C has been shown to produce electricity in a MFC. The production of pyocyanin, in combination with the formation of biofilm in the MFC anode, as observed with scanning electron microscopy (SEM) analysis, makes this P. citronellolis strain an attractive and promising candidate for wider MFC applications.

Microbial fuel cells (MFC) are an emerging technology for waste, wastewater and polluted soil treatment. In this manuscript, pollutants that can be treated using MFC systems producing energy are presented. Furthermore, the applicability of MFC in environmental monitoring is described. Common microbial species used, release of genome sequences, and gene regulation mechanisms, are discussed. However, although scaling-up is the key to improving MFC systems, it is still a difficult challenge. Mathematical models for MFCs are used for their design, control and optimization. Such models representing the system are presented here. In such comprehensive models, microbial growth kinetic approaches are essential to designing and predicting a biosystem. The empirical and unstructured Monod and Monod-type models, which are traditionally used, are also described here. Understanding and modelling of the gene regulatory network could be a solution for enhancing knowledge and designing more efficient MFC processes, useful for scaling it up. An advanced bio-based modelling concept connecting gene regulation modelling of specific metabolic pathways to microbial growth kinetic models is presented here; it enables a more accurate prediction and estimation of substrate biodegradation, microbial growth kinetics, and necessary gene and enzyme expression. The gene and enzyme expression prediction can also be used in synthetic and systems biology for process optimization. Moreover, various MFC applications as a bioreactor and bioremediator, and in soil pollutant removal and monitoring, are explored.

A Pseudomonas citronellolis strain was isolated from drilling waste (DW). This strain utilizes DW as the sole energy and carbon source to produce biosurfactants (BSs). The BS produced was thermally stable, amorphous and includes a peptide structure. FeSO₄, FeCl₃ and Fe(NO₃)₃ were supplemented at various concentration levels to assess possible enhancement of BS production and DW biodegradation. The limit concentration of Fe compounds between the increase in BS formation and microbial toxicity was 0.1 mM. FeCl₃ enhanced DW biodegradation and more than doubled the BS formation yield, determining an optimization strategy for BS production. The BS was then partially purified and used against several Gram-negative and positive multi-drug resistant bacteria (such as Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli spp, Acinetobacter baumaniii, Enterococcus faecalis spp, Streptococcus pneumoniae, Staphylococcus aureus, Salmonella enterica). The minimum inhibitory concentration was defined at a range of 0.25 to 10 mg/mL. The antimicrobial properties of the partially purified BS established its effectiveness and suggested a down-stream processing cost reduction, as no additional purification steps were necessary. The study could lead to a sustainable low-cost bioprocess towards a circular bioeconomy because waste, a non-expensive substrate, is used; while the BS holds great potential as a novel compound with antibiotic and disinfectant-like action, following toxicity testing with human cells.