Caroline Andriantsiferana

Two pigmented bacteria strains were isolated from the Mediterranean Sea. Phylogenetic analysis revealed that both strains are affiliated with Winograsdskyella schleiferi Z215. However, in contrast to this reference strain, they can assimilate additional carbon sources such as d ‐mannose, l ‐arabinose, d ‐mannitol, and citrate. Zeaxanthin was identified as the major carotenoid produced by both strains, predominantly in the all‐trans configuration. Carotenoid biosynthesis kinetics revealed that pigment production commenced at the early stages of growth, with maximal yields reached between 48 and 56 h (between 1 and 1.3 mg L ⁻¹ ). Specific production yields were 0.7 and 0.9 mg g ⁻¹ for the two strains, respectively. Total carotenoid production was influenced by incubation temperature in both strains. Overall, these findings expand the scientific knowledge on carotenoid‐producing marine bacteria and highlight the potential of these newly isolated strains as promising candidates for zeaxanthin biotechnological production for a wide range of novel applications ranging from feed additives to treatments for macular degeneration and melanoma.

The contamination of aquatic ecosystems by the micropollutants in wastewater discharges is currently a critical issue. Therefore, the development of novel treatment processes and materials is essential to ensure the availability of safe water. The present study aims to develop a photocatalytic material composed of silver nanoparticles (Ag-NPs)-doped TiO₂ supported on a Pyrex^® plate (TiO₂@Ag-NPs) exhibiting catalytic activity under visible irradiation (λ > 400 nm). The effects of Ag-NPs doping on the TiO₂ matrix, the resistance of the coating at the catalyst/substrate interface, and the photocatalytic degradation efficiency of the photocatalyst for a micropollutant (diuron) of the pesticide family were studied. The photocatalyst was characterised using X-ray diffraction, scanning electron microscopy, ultraviolet–visible spectrophotometry, and scratch tests. The solution concentrations were monitored using high-performance liquid chromatography and total organic carbon analyses. A 32% diuron removal was achieved using photocatalytic TiO₂@Ag-NPs under visible irradiation, whereas undoped TiO₂ showed no activity. Furthermore, the effects of the nanoparticle growth mode on the photocatalytic activity of TiO₂@Ag-NPs were explored. The presence of a TiO₂ sublayer ensured the adhesion of the coating and promoted the dispersion of nanoparticles within the matrix. It ensured chemical continuity (TiO₂@Ag-NPs/Pyrex^®), reduced the bandgap, and decreased electron–hole pair recombination.

By 2030, the global deficit in freshwater resources is projected to reach 40%, in direct correlation with global population growth. To cope with this increase in demand, the Sustainable Development Goals outlined by the United Nations, specifically goal No. 6 of the 2030 agenda, have identified wastewater as a new resource. Indeed, the reuse of wastewater offers three primary advantages: (i) Reused wastewater can serve as an alternative to water from natural reserves, particularly in sensitive geographical areas experiencing water stress. (ii) Wastewater reuse limits the discharge of treated water into the natural environment, which is often a source of pollution, thus helping preserve ecosystems. (iii) Wastewater reuse also facilitates the extraction of valuable compounds, such as fertilisers and precious metals, along with energy generation. This review focuses on various uses of water and the global reuse of treated wastewater from wastewater treatment plants (WWTPs). The focus then shifts to pesticides, exploring the origins of these emerging contaminants and their impacts on aquatic environments. An in-depth analysis of diuron follows, examining its origin, toxicity and regulation and the performance of existing advanced treatments to produce safe water from WWTP effluents.

Pesticides are emerging contaminants that pose various risks to human health and aquatic ecosystems. In this work, diuron was considered as a contaminant model to investigate the influence of the back-side illumination mode (BSI) on the photocatalytic activity of TiO₂ coatings grown on Pyrex plates by metal–organic chemical vapour deposition (MOCVD). A photoreactor working in recirculation mode was irradiated at 365 nm with ultraviolet A (UVA) light-emitting diodes in BSI. The degradation of diuron and its transformation products was analysed by high-performance liquid chromatography, ion chromatography, and total organic carbon analysis. The coatings were characterised by X-ray diffraction analysis and scanning electron microscopy. Five coatings containing 3, 7, 10, 12 and 27 mg of TiO₂ exhibited different morphology, crystallinity, thickness and photocatalytic activities. The morphology and crystallinity of the coatings had no significant influence on their photocatalytic activity, unlike their mass and thickness. TiO₂ contents less than 10 mg limit the photocatalytic activity, whereas those greater than 15 mg are inefficient in the BSI because of their thickness. The maximum efficiency was achieved for coatings of thickness 1.8 and 2 µm with TiO₂ contents of 10 and 12 mg, revealing that the photocatalyst thickness controls the photocatalytic efficiency in the BSI.

This work reports the performance of a sequential adsorption/photocatalysis process using activated carbon fibers with deposited TiO2 for the elimination of the antibiotic ciprofloxacin (CIP) in water. A commercial activated carbon fiber (ACF10) was selected as the support, and a TiO2 coating was synthesized using Metal Organic Chemical Vapor Deposition (MOCVD). Experiments were carried out using a photocatalytic reactor irradiated with monochromatic LEDs (365nm). Two different processes have been studied: adsorption/photolysis and adsorption/photocatalysis. The objective was to completely remove the CIP and to evaluate the efficiency of the treatment by following the formation/elimination of aromatic transformation products (ATPs), aliphatic acids, fluoride, and the TOC in the liquid phase. The adsorption kinetic of the CIP by ACF10 was rather slow (71% of CIP adsorbed by 24 h and total adsorption by 20 days). A good fit between the external diffusion limitation model and the experimental curve (kext = 0.0056 h-1) showed an external transfer limitation due to a tight weave of fibers. For the adsorption/photolysis process, a significant decrease of the concentration was achieved (95% after 6 h of irradiation), but ten different ATPs were detected in the liquid phase. To eliminate CIP, 24 h of adsorption and 6 h of irradiation were then necessary, but most of the ATPs remained in solution (total treatment duration: 72 h). With ACF10-TiO2, the same ATPs were present in solution and were eliminated after the 6 h irradiation step (total treatment duration: 30 h). At the end of the treatment, several non-toxic aliphatic acids were found to be present, showing the higher efficiency of this sequential process. The presence of a significant amount of fluorine in the liquid phase suggests some surface photochemical reactions of the adsorbed molecules (CIP and transformation products) and a partial regeneration of the composite material.

Fluoroquinolones are extensively used in medicine due to their antimicrobial activity. Their presence in water inhibits microorganism activity in conventional wastewater treatment plants. This study aims to evaluate the technical feasibility of applying heterogeneous catalytic ozonation to eliminate ciprofloxacin (CIP) as a representative of fluoroquinolone antibiotics normally present in municipal wastewater discharges. Experiments were conducted in a semi-batch stirred slurry reactor, using 0.7 L of 100 mg L⁻¹ CIP aqueous solution, at pH 3 and 30 °C. Experimental results show that single ozonation can easily oxidise CIP molecules (68%) within the first 5 min, leading to the generation of refractory oxidation by-products. However, when heterogeneous catalytic ozonation is applied using iron oxide supported on MFI synthetic zeolite, total degradation of CIP is observed at 5 min and a higher mineralisation rate is obtained. A novel sequential process is developed for CIP mineralisation. In a first step, a flash single ozonation is applied and CIP molecules are broken down. Then, a catalytic ozonation step is conducted by adding the Fe/MFI catalyst into the reactor. As a result of catalyst addition, 44% of Total Organic Carbon (TOC) is eliminated within the first 15 min, compared to single ozonation where only 13% of TOC removal is reached in the same time. The application of this sequential process to a real wastewater effluent spiked with CIP leads to 52% of TOC removal.

Ochratoxin A (OTA) is a mycotoxin produced by several species of Aspergillus and Penicillium that contaminate food and feed raw materials. To reduce OTA contamination, we first tested in vitro, actinobacterial strains as potential biocontrol agents and afterward, through a physical decontamination method using activated carbon fibers (ACFs). Actinobacterial strains were screened for their ability to reduce OTA in solid co-culture with A. carbonarius, which is the major OTA-producing species in European vineyards. Four strains showed a high affinity for removing OTA (67%–83%) with no significant effect on fungal growth (acOTApks, acOTAnrps, acOTAhal) by RT-qPCR showing a drastic reduction in all genes (7–15 times). Second, the ability of these strains to degrade OTA was assessed in vitro on ISP2 solid medium supplemented with OTA (100 µg/L). Two strains reduced OTA to undetectable levels. As for the physical method, high adsorption rates were obtained for ACFs at 0.8 g/L with a 50% adsorption of OTA in red wine by AC15 and 52% in grape juice by AC20 within 24 h. These promising methods could be complementarily applied toward reducing OTA contamination in food chains, which promotes food safety and quality.

For several decades, it has been known that ozone emissions are harmful to humans, plants, and animals. Heterogeneous catalytic decomposition is an efficient process for removing ozone from air. This study examines the effect of the zeolite's framework and pore width on efficiency for decomposing gaseous ozone. Four highly hydrophobic zeolites are used: a large cavity zeolite (Faujasite/H‐FAU), a medium pore zeolite with parallel channel (Mordenite/H‐MOR), and two medium pore zeolites with interconnected channels (H‐ZSM‐5/H‐MFI and Na‐ZSM‐5/Na‐MFI). Experiments were conducted in fixed‐bed flow reactors loaded with zeolite at ambient conditions (20 °C and 101 kPa). Zeolite surfaces were analyzed during the experiments in order to understand the influence of physical and chemical surface properties on the ozone decomposition mechanism. A higher amount of ozone is eliminated using H‐MOR, compared with the zeolite samples H‐FAU, H‐MFI, and Na‐MFI. Pore width and micropore framework size distribution (channel and cages) appear to be key factors. A narrow channel or cage, slightly larger than the ozone molecule size, seems to promote ozone interactions with Lewis acid sites. Fourier transform infrared spectroscopy shows that Lewis acid sites (LAS), located on the walls of zeolite pores, decompose ozone. This leads to the formation of atomic oxygen species that could react with another ozone molecule to form dioxygen. Hence, LAS are regenerated, ready to decompose another ozone molecule once more.

The present study aimed to prepare catalysts of Fe- and Cu-loaded zeolite via ion-exchange technique using dilute solutions of metal nitrate precursors followed by calcination at 600°C in the air for 4 h. Commercial zeolite ZSM-5 with specific surface area of 400 m²/g and diameter particle of 1.2–2 mm was used as a parent support. The prepared catalysts were characterized by Fourier transform infrared spectroscopy analysis. The IR absorbed bands of Cu-ZSM-5 and Fe-ZSM-5 revealed a shift in the frequency and a reduction in the intensity framework. This indicates that both catalysts have a significant change in the number of the zeolite structure bonds. The catalytic activity of the prepared materials compared to the parent zeolite was evaluated for the catalytic ozone decomposition. The ozone stream of the initial concentration (13 g/m³) with air flow rate (Q) of 0.18 m³/h was passed through a glass jacket column reactor filled with a fixed bed of 40 g zeolites. It was showed that the ozone removal efficiency by Cu-ZSM-5 and Fe-ZSM-5 was obviously higher than that found with the parent ZSM-5. In terms of O₃ removal efficiency, zeolite samples could be ranked as follows: Fe-ZSM-5 > Cu-ZSM-5> parent ZSM-5. The results revealed about 90% O₃ removal efficiency for Fe-ZSM-5 and 70% for Cu-ZSM-5 as compared to nearly 40% for the parent zeolite. Consequently, the incorporation of Fe and Cu metals onto the zeolite surface plays a key role for enhancing the gaseous ozone elimination.