Fucoxanthin was purified and quantified from the marine diatom Navicula salinicola, identified using genetic markers. The enzymatic inhibitory activities and cytotoxic effects of the extracts and purified pigment were evaluated in vitro, while enzyme inhibition was further examined in silico. Cultivation under moderate light intensity supported efficient biomass production (0.46 ± 0.02 g L⁻1 day⁻1) and enhanced fucoxanthin accumulation (9.42 ± 0.08 mg g⁻1 ash-free dry weight). Fucoxanthin productivity reached a maximum of 4.33 ± 0.02 mg L⁻1 day⁻1 under these conditions, reflecting an optimal balance between biomass production and intracellular pigment accumulation. HPLC–MS analysis confirmed that the extract was rich in xanthophylls, with fucoxanthin as the predominant compound. Centrifugal partition chromatography enabled effective fractionation of the extract, yielding fucoxanthin with a recovery of 7.46 ± 0.10 mg g⁻1 ash-free dry weight and a purity of 91

Microplastics (MPs) are well-recognized as vectors for microbial colonization, forming complex biofilms known as the plastisphere. In this study, we investigated the colonization of four common plastic polymers, namely Linear Low Density Polyethylene (LLDPE), Polyethylene Terephthalate (PET), Polystyrene (PS), and Polyvinyl Chloride (PVC) with an average size range of 3.2-4.1 mm by marine microorganisms under natural shallow coastal water column conditions (∼2 m depth) near the fishing port of Gabès, in southeastern Tunisia (Gulf of Gabès, southern Mediterranean Sea). Biofilms were monitored over 7, 30, and 90 days using 16S rRNA gene amplicon sequencing to assess the simultaneous effect of exposure time and polymer type. Temporal succession emerged as the dominant driver of plastisphere composition, with PERMANOVA revealing that exposure time explained 58% of the total community variance (p = 0.001), while polymer type accounted for 15% (p = 0.001). Distance-based redundancy analysis (db-RDA) further demonstrated that this successional trajectory was closely associated with seasonal environmental shifts. Proteobacteria, Campylobacterota, Bacteroidota, and Actinobacteriota dominated the plastisphere, with Rhodobacteraceae, Saprospiraceae, and Flavobacteriaceae consistently established throughout. Putative hydrocarbonoclastic and plastic-associated taxa were detected at different stages of biofilm development, alongside organisms promoting biofilm cohesion. PET supported the most diverse biofilm, harboring approximately 2400 ASVs, including nearly 900 unique ASVs, after three months of exposure, whereas PVC hosted the most distinct microbial communities.

Coral reefs in the Arabian Gulf are exposed to extreme temperatures and salinities, resulting in some of the highest coral bleaching and mortality rates worldwide. Preserving heat-tolerant Symbiodiniaceae is therefore an urgent priority to sustain coral resilience and support emerging restoration and assisted-evolution strategies. Existing cryopreservation protocols for Symbiodinium are technically demanding, costly, and may compromise long-term cell viability, limiting their applicability in resource-constrained settings. This study reports the molecular taxonomic identification, growth characteristics, and long-term performance of a Symbiodinium sp. Clade A strain isolated from the brain coral Platygyra daedalea under a simple, non-cryogenic preservation regime. Under controlled laboratory conditions (40 ps mu, 26 degrees C, 130 mu mol photons m- 2 s-1, 12:12 h light:dark), the strain exhibited a high maximum growth rate of 0.50 +/- 0.03 day- 1, indicating strong physiological performance in the Arabian (Persian) Gulf conditions. To evaluate a non-cryogenic preservation approach, cultures were stored under continuous light or complete darkness for 1, 3, and 6 months. Light-based storage consistently supported post-preservation recovery, maintaining culturability and higher growth rates across all time points, whereas dark storage resulted in pronounced declines in growth and viability, particularly after 6 months, when cell viability was up to 12-fold lower than control conditions. Prolonged storage was also associated with an extended lag phase during post-incubation recovery, proportional to storage duration. These results demonstrate that lightbased, non-cryogenic storage provides an effective, low-cost alternative to conventional cryopreservation for Symbiodinium sp. Clade A and offers a practical tool for long-term maintenance of symbiont cultures to strengthen ex situ in coral conservation, potential symbiont banking, and restoration initiatives in thermally extreme reef systems.

Recent geological, hydrochemical, and mineralogical studies performed on hypersaline salt flats have given insights into similar geo-morphologic features on Mars. These salt-encrusted depressions are widely spread across the Earth, where they are characterized by high salt concentrations, intense UV radiation, high evaporation, and low precipitation. Their surfaces are completely dry in summer; intermittent flooding occurs in winter turning them into transitory hypersaline lakes. Thanks to new approaches such as culture-dependent, culture-independent, and metagenomic-based methods, it is important to study microbial life under polyextreme conditions and understand what lives in these dynamic ecosystems and how they function. Regarding these particular features, new halophilic microorganisms have been isolated from some salt flats and identified as excellent producers of primary and secondary metabolites and granules such as halocins, enzymes, carotenoids, polyhydroxyalkanoates, and exopolysaccharides. Additionally, halophilic microorganisms are implemented in heavy metal bioremediation and hypersaline wastewater treatment. As a result, there is a growing interest in the distribution of halophilic microorganisms around the world that can be looked upon as good models to develop sustainable biotechnological processes for all fields. This review provides insights into diversity, ecology, metabolism, and genomics of halophiles in hypersaline salt flats worldwide as well as their potential uses in biotechnology.

This work focused on the biotreatment of wastewater and contaminated soil in a used oil recycling plant located in Bizerte. A continuous stirred tank reactor (CSTR) and a trickling filter (TF) were used to treat stripped and collected wastewater, respectively. The CSTR was started up and stabilized for 90 days. Over the following 170 days, the operational organic loading rates of the TF and the CSTR were around 1,200 and 3,000 mg chemical oxygen demand (COD) L-1 day(-1), respectively. The treatment efficiency was 94% for total petroleum hydrocarbons, 89.5% for COD, 83.34% for biological oxygen demand (BOD5), and 91.25% for phenol. Treated industrial wastewater from the TF was used for bioaugmentation (BA) of contaminated soil. The assessment of the soil took 24 weeks to complete. The effectiveness of the soil BA strategy was confirmed by monitoring phenolic compounds, aliphatic and polycyclic aromatic hydrocarbons, heavy metals, and germination index. The biodegradation rate of contaminants was improved and the time required for their removal was reduced. The soil bacterial communities were dominated by species of the genera Mycobacterium, Proteiniphilum, Nocardioides, Luteimicrobium, and Azospirillum, which were identified as hydrocarbon and phenol-degrading bacteria.

The aim of the present study is to investigate the adsorption of dissolved organic matter in olive mill wastewater (OMW) onto biochar as a pretreatment step within an eco-friendly OMW management process. Firstly, the adsorption kinetics and adsorption isotherm were studied. Then, an experimental design was used in a sequential approach in order to evaluate the effects of factors that potentially influence the adsorption efficiency. Results showed that the OMW adsorption kinetics were governed by a pseudo-first-order model, while Freundlich and Redlich–Peterson models described the isotherm data well. It was also demonstrated that linear fitting is a limited method when applied to kinetics and isotherm modeling. Alternatively, nonlinear fitting is recommended for the appropriate modeling of adsorption data. Experimental design results showed that the organic matter removal percentage and biochar uptake capacity were oppositely sensitive to OMW concentration and biochar mass. Organic matter removal reached a maximum value of 28

In the field of innovative challenges, it is essential to incorporate microorganisms into agricultural practices that promote and improve plant growth and health, particularly under conditions of salinity stress. This work elucidated the response of two Opuntia ficus-indica cultivars (spiny, Gialla and spineless, Rossa) inoculated inland with a coastal cactus rhizospheric soil (Opuntia littoralis) under NaCl treatment. The two cultivars reacted differently to salinity stress. The cladodes and roots of the Rossa cultivar were sensitive to salinity and accumulated both Na+ and Cl-. In contrast, the Gialla cultivar showed Na+ exclusion from the cladodes and root growth was unaffected by salinity. The diversity, richness, and correlation networks of root compartments bacterial communities were mainly determined while the cactus cultivar was subjected to salinity stress. Different subsets of key soil bacteria taxa were selected by the root systems of each cultivar after exposure to salinity. Our results highlight the importance of the rhizosphere of endemic coastal plants in improving plant resistance to salinity stress, particularly in the spiny cultivar compared to the spineless cultivar. The microbiome networks provide solid evidence that each cultivar adapts its bacterial community composition and interactions in response to salinity.

This work focused on the biotreatment of wastewater and contaminated soil in a used oil recycling plant located in Bizerte. A Continuous Stirred Tank Reactor (CSTR) and a Trickling Filter (TF) were used to treat stripped and collected wastewater, respectively. The CSTR was started up and stabilized for 90 days. Over the following 170 days, the operational organic loading rates (OLR) of the TF and the CSTR were around 1200 and 3000 mg chemical oxygen demand (COD) L -1 day -1 , respectively. The treatment efficiency was 94% for total petroleum hydrocarbons (TPH), 89.5% for COD, 83.34% for biological oxygen demand (BOD 5 ) and 91.25% for phenol. Treated industrial wastewater from the TF was used for bioaugmentation (BA) of contaminated soil. The BA strategy was compared with natural attenuation (NA) based on the use of tap water. The assessment of the soil took 24 weeks to complete. The effectiveness of the soil bioaugmentation strategy was confirmed by monitoring of phenolic compounds, aliphatic and polycyclic aromatic hydrocarbons (AH and PAH), heavy metals and germination index (GI). The biodegradation rate of contaminants was improved and the time required for their removal was reduced. The soil bacterial communities were dominated by species of the genera Mycobacterium , Proteiniphilum, Nocardioides, Luteimicrobium and Azospirillum , which were identified as hydrocarbon and phenol degrading bacteria. The bioremediation of polluted soils by the treated industrial effluents seems to be an interesting approach for the conservation of water and soil resources.

Polyhydroxyalkanoates (PHAs), green alternatives to petroleum-derived plastics, possess desired features that make them preferred for various applications. Poly(3-hydroxybutyrate) (PHB), one of the most known representative of PHAs, could be synthesized by haloarchaeal species but their production amounts are relatively low compared to those of poly(3-hydroxybutyrate-co-hydroxyvalerate) (PHBV) obtained by haloarchaea. This is the first report describing an overproduction of PHB by a wild-type halophilic archaeon isolated from southern Tunisia, Chott El Jerid. According to the 16S rRNA gene sequence analysis, the isolate CEJ40-10 was affiliated with the species of the genus Haloarcula (97.5

The current research work attempted to investigate, for the first time, the impact of biochar addition, on anaerobic digestion of olive mill wastewater with different initial chemical oxygen demand loads in batch cultures (10 g/L, 15 g/L, and 20 g/L). Methane yields were compared by applying one-way analysis of variance (ANOVA) followed by post-hoc Tukey’s analysis. The results demonstrated that adding at 5 g/L biochar to olive mill wastewater with an initial chemical oxygen demand load of 20 g/L increased methane yield by 97.8% and mitigated volatile fatty acid accumulation compared to the control batch. According to the results of microbial community succession revealed by the Illumina amplicon sequencing, biochar supplementation significantly increased diversity of the microbial community and improved the abundance of potential genera involved in direct interspecies electron transfer, including Methanothrix and Methanosarcina. Consequently, biochar can be a promising alternative in terms of the recovery of metabolic activity during anaerobic digestion of olive mill wastewater at a large scale.

In the context of climate change leading to water scarcity for many people in the world, the treatment of municipal wastewater becomes a necessity. However, the reuse of this water requires secondary and tertiary treatment processes to reduce or eliminate a load of dissolved organic matter and various emerging contaminants. Microalgae have shown hitherto high potential applications of wastewater bioremediation thanks to their ecological plasticity and ability to remediate several pollutants and exhaust gases from industrial processes. However, this requires appropriate cultivation systems allowing their integration into wastewater treatment plants at appropriate insertion costs. This review aims to present different open and closed systems currently used in the treatment of municipal wastewater by microalgae. It provides an exhaustive approach to wastewater treatment systems using microalgae, integrating the most suitable used microalgae species and the main pollutants present in the treatment plants, with an emphasis on emerging contaminants. The remediation mechanisms as well as the capacity to sequester exhaust gases were also described. The review examines constraints and future perspectives of microalgae cultivation systems in this line of research.

Recently, the use of microalgae in the treatment of olive mill wastewater as a safe method for reducing pollutants has gained more attention. However, the contribution of such by-product to the improvement of the pharmacological properties addressing the health benefits of Scenedesmus sp., as a cosmetic remedy or food ingredient, is not sufficiently available. To address this issue, Scenedesmus sp. was cultivated in BG11 medium enriched or not with 20

Agroforestry (AF) is a promising land-use system to mitigate water deficiency, particularly in semi-arid areas. However, the belowground microbes associated with crops below trees remain seldom addressed. This study aimed at elucidating the effects of olive AF system intercropped with durum wheat (Dw), barely (Ba), chickpea (Cp), or faba bean (Fb) on crops biomass and their soil-rhizosphere microbial networks as compared to conventional full sun cropping (SC) under rainfed conditions. To test the hypothesis, we compared the prokaryotic and the fungal communities inhabiting the rhizosphere of two cereals and legumes grown either in AF or SC. We determined the most suitable annual crop species in AF under low-rainfed conditions. Moreover, to deepen our understanding of the rhizosphere network dynamics of annual crops under AF and SC systems, we characterized the microbial hubs that are most likely responsible for modifying the microbial community structure and the variability of crop biomass of each species. Herein, we found that cereals produced significantly more above-ground biomass than legumes following in descending order: Ba > Dw > Cp > Fb, suggesting that crop species play a significant role in improving soil water use and that cereals are well-suited to rainfed conditions within both types of agrosystems. The type of agrosystem shapes crop microbiomes with the only marginal influence of host selection. However, more relevant was to unveil those crops recruits specific bacterial and fungal taxa from the olive-belowground communities. Of the selected soil physicochemical properties, organic matter was the principal driver in shaping the soil microbial structure in the AF system. The co-occurrence network analyses indicated that the AF system generates higher ecological stability than the SC system under stressful climate conditions. Furthermore, legumes' rhizosphere microbiome possessed a higher resilient capacity than cereals. We also identified different fungal keystones involved in litter decomposition and drought tolerance within AF systems facing the water-scarce condition and promoting crop production within the SC system. Overall, we showed that AF reduces cereal and legume rhizosphere microbial diversity, enhances network complexity, and leads to more stable beneficial microbial communities, especially in severe drought, thus providing more accurate predictions to preserve soil diversity under unfavorable environmental conditions.

Surface seawater, collected from three fishing harbors during different seasons of the years 2015, 2016 and 2017, were assessed for physico-chemical analyses. Results showed that seawater was mainly polluted by hydrocarbons and some heavy metals. Microbial communities' composition and abundance in the studied harbors were performed using molecular approaches. SSCP analysis indicated the presence of Bacteria, Archaea and Eucarya, with dominance of the bacterial domain. Illumina Miseq analysis revealed that the majority of the sequences were affiliated with Bacteria whereas Archaea were detected at low relative abundance. The bacterial community, dominated by Proteobacteria, Bacteroidetes, Planctomycetes, Cyanobacteria, Firmicutes, Actinobacteria and Chloroflexi phyla, are known to be involved in a variety of biodegradation/biotransformation processes including hydrocarbons degradation and heavy metals resistance. The main objectives of this study are to assess, for the first time, the organic/inorganic pollution in surface seawater of Kerkennah Islands harbors, and to explore the potential of next generation marine microbiome monitoring to achieve the planning coastal managing strategies worldwide.

Anaerobic digestion is an attractive approach for the management of organic fraction of municipal solid waste (OFMSW) and for the recovery of energy from this waste. A semi-continuous digestion of OFMSW was conducted on stirred reactor under mesophilic condition. Three organic loading rates (OLRs) were tested throughout the anaerobic process (1.36, 2.5 and 3.5 g VS/L.d). The achieved results showed that biogas yield decreased with the increase of OLR. Thus, the highest average of biogas yield, 0.51 L/g VS, was recorded at low OLR (OLR1:1.36 gVS/L.d). Likewise, optimal VS removal, pH, VFA and alkalinity were obtained at OLR1 compared to the other tested OLR. During the anaerobic digestion, the dynamic of microbial community was also assessed by the high-throughput sequencing technology. Firmicutes, Bacteroidetes and Proteobacteria were the dominant phyla during the digestion process. This could be related to their roles in hydrolysis of different OFMSW compounds, as well as in acidogenesis and acetogenesis steps. Regarding Archaeal population, the relative abundance of the Methanoculleus genus declined, while Methanosarcina increased over time. This indicated that acetotrophic and hydrogenotrophic pathways were used for methane production.

The beneficial effect of compost and compost tea on plant growth and protection is mainly associated with the microbial diversity and the presence of bacteria with plant growth–promoting effect. PGPR are considered as eco-friendly bio-fertilizers that may reduce the use of chemical pesticides and fertilizers. Three composts (AT, A10, and A30) were previously prepared from industrial wastes (olive mill wastewater, olive pomace, coffee ground, and phosphogypsum). In the present study, we isolated three bacterial strains from the compost teas. The phylogenetic identification of these bacterial strains (B.AT, B.A10, and B.A30) showed that they correspond to Serratia liquefaciens (B.AT and B.A10) and Achromobacter spanius (B.A30) species. A further characterization of the PGPR traits of these bacteria showed that they produce siderophore, exopolysaccharides, and IAA. Their effect on potato plant growth, yields, and tuber quality was performed under field culture conditions. Results showed that these strains can be characterized as PGPR, the best effect on potato plant growth was observed with Serratia liquefaciens (B.AT), the best yield and tuber quality was observed with Serratia liquefaciens (B.A10) while bacterial treatment with Achromobacter spanius (B.A30) is a Cd-tolerant PGPR.

Probiotics or direct-fed microbials (DFM) have proven strong potential for improving aquaculture sustainability. This study aims to evaluate the effects of dietary supplementation with the DFM Bacillus amyloliquefaciens US573 on growth performance, intestinal morphology, and gut microbiota (GM) of European sea bass. For this purpose, healthy fish were divided into two feeding trials in triplicate of 25 fish in each tank. The fish were fed with a control basal diet or a DFM-supplemented diet for 42 days. Results showed that, while no significant effects on growth performance were observed, the length and abundance of villi were higher in the DFM-fed group. The benefic effects of DFM supplementation included also the absence of cysts formation and the increase in number of goblet cells playing essential role in immune response. Through DNA metabarcoding analysis of GM, 5 phyla and 14 major genera were identified. At day 42, the main microbiome changes in response to B. amyloliquefaciens US573 addition included the significant decrease in abundance of Actinobacteria phylum that perfectly correlates with a decrease in Nocardia genus representatives which represent serious threat in marine and freshwater fish. On the contrary, an obvious dominance of Betaproteobacteria associated with the abundance in Variovorax genus members, known for their ability to metabolize numerous substrates, was recorded. Interestingly, Firmicutes, particularly species affiliated to the genus Sporosarcina with recent promising probiotic potential, were identified as the most abundant. These results suggest that B. amyloliquefaciens US573 can be effectively recommended as health-promoting DFM in European sea bass farming.

The electro-Fenton (EF) disintegration using iron electrodes was performed for the pretreatment of waste activated sludge (WAS). The effect of this electro-chemical pretreatment on anaerobic digestion (AD) performance and microbial population structure was studied. An improvement of biodegradability and bioaccessibility of organic matter was demonstrated. AD of pretreated WAS in an up-flow anaerobic sludge blanket reactor (UASB) resulted to an increase of biogas production by 60 % compared to control reactor without disintegration. PCR-DGGE and real-time qPCR analyses showed that the high abundance of bacteria and the coexistence of Coprothermobacter in the UASB digestate fed with disintegrated sample established a stable bacterial association which is in line with the AD performance. Besides, the increased number of methanogens along the process allowed the improvement of methane production in comparison to control reactor.

BACKGROUND The three-phase extraction process of olive oil produces highly contaminated wastewater (OMW). The elimination of this toxic by-product is an important environmental issue that requires the development of an appropriate management solution. The cultivation of microalgae using OMW as growth medium was therefore studied using single (the culture medium was formed by 0% to 80% ultrafiltered olive mill wastewater (OMUF) or OMW added to BG11) and two-stage strategies (microalgae were firstly cultivated in the BG11 medium. In the second stage, 40% and 80% of OMUF and OMW were added to the culture). In this work, biodegradation of OMW and subsequent extraction of lipid and antioxidant molecules was investigated as an ecofriendly method for the bioremediation and valorization of OMW. RESULTS For two-stage cultivation, OMUF and OMW stress enhanced the intracellular amount of polyphenol accumulated in Scenedesmus sp. and exhibited the highest 2, 2-diphenyl-1- picrylhydrazyl radical (DPPH) and 2,2'-azino-bis (3-ethylbenzoline-6-sulfonate) radical (ABTS) scavenging ability compared with single-stage cultivation. Moreover, the lipid profile is dominated by polyunsaturated acids. In the single-stage cultivation, the Ch a, Ch b, carotenoid, carbohydrate and lipid content of 2.57, 7.4, 1.69, 368, and 644 g kg(-1) were observed in 40% OMUF added culture, respectively, along with high biomass productivity and 58% of polyphenol removal. Moreover, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that the biomass of Scenedesmus sp. cultured on 40% OMUF did not show any toxic effect, making it an efficient strategy. CONCLUSION The results indicate that Scenedesmus sp. is a promising microalga for the biotreatment of OMW and the extraction of bioactive metabolites. (c) 2021 Society of Chemical Industry.