Search Results (306)

This study evaluated the effects of tamarind (Tamarindus indica L.) pulp as a marinade on the physicochemical quality (marinade liquid uptake, water-holding capacity, cooking loss, proximate composition, water activity, pH, color, and texture), oxidative stability (lipid oxidation), microbiological characteristics (mesophilic aerobic counts, Enterobacteriaceae, Gram-positive cocci, and molds and yeasts), and sensory attributes of eye of round beef (M. semitendinosus). Three treatments were compared: non-marinated control (C), brine (B; 2.5% NaCl), and NaCl with tamarind pulp (BPT; 2.5% NaCl + tamarind pulp). Tamarind incorporation significantly reduced pH and water-holding capacity, resulting in lower moisture content and higher ash and carbohydrate levels. BPT samples exhibited increased lightness (L*) and yellowness (b*) and reduced redness (a*), reflecting pigment contribution and acid-induced structural modifications. Texture profile analysis showed lower hardness and chewiness in BPT throughout storage, demonstrating improved tenderness. Lipid oxidation increased in B but remained controlled in BPT, highlighting the antioxidant potential of tamarind pulp. Tamarind selectively improved the microbiological profile by inhibiting Enterobacteriaceae and reducing mesophilic aerobic bacteria, although it was less effective in controlling molds and yeasts. Sensory evaluation showed that B treatment received the highest scores for flavor and overall acceptability, while BPT was characterized by fruity, acidic, and sweet notes, resulting in a distinctive sensory profile without reducing acceptability relative to the control. Overall, tamarind pulp substantially modulated the quality characteristics of marinated eye of round beef, providing advantages in oxidative stability, microbial control, and texture while also reducing water-holding capacity, altering color, increasing mold and yeast growth, and producing a distinctive sensory profile. These findings highlight both the potential and the limitations of tamarind pulp as a natural ingredient for clean-label meat products. Full article

Bacterial disease is a major constraint on Magallana gigas larval production, yet hatchery microbiology has been characterised almost exclusively through the lens of Vibrio, and rarely across the whole production chain. We tracked bacterial communities throughout an entire larval rearing cycle at a commercial hatchery in northern China. A total of 78 samples were collected from the full production chain, from water intake to larvae. Bacterial communities were characterised using 16S rRNA (V4–V5) amplicon sequencing and culture-based isolation, with larvae sampled from three replicate tanks at six developmental stages. A protracted mortality event began at the D-veliger stage, with cumulative losses of roughly 40% before sinking ceased; ostreid herpesvirus 1 was not detected. The only taxon that rose above its healthy baseline during larval mortality was a single undescribed a single undescribed amplicon sequence variant (ASV) of the family Cryomorphaceae. Its relative abundance increased to a mean of 41% (with a tank-to-tank range of 33.7–51.6%) before disappearing once the mortality event concluded. No described species exceeds 92.2% 16S rRNA gene sequence identity to it, whereas its closest environmental relatives (97–98%) are, without exception, uncultured bacteria associated with marine invertebrates. It was an order of magnitude more abundant in larvae than in the surrounding water. Vibrio rose transiently at the onset of mortality but fell below its healthy-stage abundance while larvae were still dying. Tenacibaculum, by contrast, was the dominant genus of the rearing water yet was never recovered on Vibrio-selective medium and showed no association with mortality. Chlorination of the feed-room supply removed Tenacibaculum while leaving Vibrio uncontrolled. These findings reveal the limitations of the Vibrio-targeted, culture-based paradigm that has long dominated hatchery microbiology, as it overlooks both prevailing water-column organisms and mortality-linked taxa. Our results highlight the need for whole-community, culture-independent surveillance to better understand larval disease. Full article

The accumulation and persistence of plastic waste have made microbial plastic biodegradation an important topic in pollution control, environmental remediation, and sustainable materials management. This study combines a mini-review with bibliometric analysis to link mechanistic understanding with global research trends in microbial plastic biodegradation from 2000 to 2025. The mini-review summarizes polymer weathering and fragmentation, microbial colonization and biofilm formation, extracellular depolymerization or oxidative chain cleavage, uptake and intracellular catabolism of plastic-derived intermediates, physiological regulation, ecological interactions, and potential applications in bioremediation and upcycling. Bibliographic records were retrieved from the Web of Science Core Collection and analyzed using bibliometrix, VOSviewer, CiteSpace, and SCImago Graphica. A total of 2959 publications were identified. Publication output increased markedly, especially after 2018, reaching 617 publications in 2025; cumulative citations reached 31,373. China, India, and the United States were the leading contributors. Journal and keyword analyses showed strong links among environmental science, polymer science, microbiology, biotechnology, and engineering. Highly cited publications mainly focused on plastic biodegradability, biodegradable polymers, engineered PET depolymerization, polyethylene degradation, and microbial or enzymatic degradation mechanisms. Keyword evolution revealed a shift from material-oriented topics, including polymer blends, poly(vinyl alcohol), polyesters, morphology, mechanical properties, composites, and polyhydroxyalkanoates, toward degrading enzymes, cutinase-like enzymes, plastic-degrading strains, microbial colonization, fungi, and marine environmental degradation. Overall, microbial plastic biodegradation has evolved from material-centered biodegradability evaluation toward a mechanism-oriented and environment-oriented interdisciplinary field. Full article

This study investigated microbiologically influenced corrosion (MIC) and passive-film degradation of a Ti-15Mo-3Al-2.7Nb-0.25Si β titanium alloy exposed to Pseudomonas aeruginosa. The alloy comprised a continuous β-Ti matrix with dispersed α-Ti precipitates, and this α/β dual-phase microstructure provided a potential microstructural basis for spatial variations in passivation behavior among different microregions. During immersion, P. aeruginosa formed a heterogeneous biofilm of bacterial cells and extracellular polymeric substances, altering interfacial mass transfer, oxygen distribution, and local chemistry. Relative to the sterile control, the inoculated group showed increases in maximum pit depth from 2.4 to 4.1 μm and corrosion current density from 8.72 to 17.2 nA cm⁻², while the charge-transfer resistance decreased to 4.32 MΩ cm² after 14 d, confirming enhanced localized corrosion. Mott-Schottky and XPS analyses showed that the donor density increased from 1.07 × 10¹⁹ to 1.29 × 10¹⁹ cm⁻³ and the Ti⁴⁺ fraction decreased from 72.29% to 66.74% and the relative Ti⁰ fraction increased from 7.01% to 17.59%, reflecting increased defect accumulation within the film, impaired passive-film integrity, and reduced local protective capability. P. aeruginosa therefore increases the MIC susceptibility of this β titanium alloy by biofilm-induced interfacial microenvironmental heterogeneity. These findings support MIC assessment and integrated antifouling-anticorrosion surface design for marine β titanium alloys. Full article

Planktothrix species are among the most widespread bloom-forming cyanobacteria in freshwater ecosystems and are of particular concern because of their ability to produce cyanotoxins and form persistent harmful algal blooms (HABs). Among them, Planktothrix agardhii and Planktothrix rubescens are the most extensively studied species and are responsible for a large proportion of bloom events reported in European lakes. This review synthesizes current knowledge on the taxonomy, ecophysiology, toxin production, environmental drivers, species interactions, and management of Planktothrix blooms, with a particular focus on European freshwater ecosystems. The available evidence highlights marked ecological differences between the two dominant species. P. agardhii is primarily associated with shallow, eutrophic, and well-mixed lakes, whereas P. rubescens is typically found in deep, stratified, and relatively transparent water bodies, where it forms persistent metalimnetic populations. These contrasting ecological strategies influence bloom development, toxin dynamics, detection, and management. Nutrient availability, light climate, temperature, water column stability, and biological interactions all contribute to bloom establishment and persistence, while climate change is expected to further modify bloom frequency, duration, and geographic distribution. The review also examines current monitoring and mitigation approaches, highlighting the limitations of conventional surface-based surveys for detecting deep P. rubescens populations and emphasizing the need for integrated monitoring strategies combining depth-resolved sampling, molecular tools, and toxin analyses. Overall, understanding the ecological and physiological diversity of Planktothrix species is essential for improving risk assessment, developing effective management measures, and mitigating the impacts of cyanobacterial blooms in European freshwaters. Full article

Ornamental aquarium keeping collectively involves millions of freshwater, marine, and reef systems in which fish, corals, invertebrates, biofilters, microbial communities, and human husbandry practices are closely interconnected. In these domestic aquatic animal systems, preventive and curative treatments may include antimicrobials, antiparasitics, antiseptics, oxidizing agents, copper-based products, dips, and commercial formulations targeting microbial proliferations or visible system deterioration. Many interventions occur without veterinary diagnosis, microbiological confirmation, standardized dosing, active-ingredient transparency, or post-treatment monitoring. This raises concerns for aquatic animal health and welfare, as whole-system treatments may affect not only the intended pathogen or pest but also non-target organisms, biofilter communities, animal-associated microbiota, and water quality stability. Digital communities and online platforms can rapidly circulate empirical treatment protocols, although they may also provide opportunities for stewardship education and improved husbandry guidance. Current evidence does not support interpreting ornamental aquaria as major independent drivers of antimicrobial resistance. The more defensible concern is stewardship: biologically active compounds may be used repeatedly and empirically in animal systems without diagnosis, professional guidance, or systematic monitoring. This Perspective argues that ornamental aquaria should be recognized as an overlooked interface between aquatic animal health, welfare, antimicrobial stewardship, and One Health. It proposes a research and communication agenda focused on treatment transparency, diagnosis, prevention, biofilter protection, and responsible care practices. Full article

Marine algal viruses exhibit a high level of diversity, and closely related viruses targeting the same algal host species can stably coexist. Here we report an example of a single virus–host system concealing hidden complexity. We discovered two double stranded (ds) DNA viruses infecting the Arctic picophytoplankter Micromonas polaris coexisting in culture for over a decade. Genomic sequencing of the lysate originally characterized as MpoV-44T revealed that it comprises two distinct prasinoviruses with ~203–204 kb genomes (MpoV-44T.A and MpoV-44T.B), of which conserved regions only accounted for 36% (the nucleotide level). The viruses were subsequently separated and compared at both genomic and phenotypic levels. In dual infection studies using a single host strain under nutrient-replete conditions, MpoV-44T.A outcompeted MpoV-44T.B. Yet MpoV-44T.B-like viruses were more abundant than MpoV-44T.A-like ones in natural Arctic metagenomes. This apparent paradox may be explained by differences in host strain specificity and/or possible resilience to nutrient stress by MpoV-44T.B, which we hypothesize based on genomic data. This work unveils hidden virus diversity, illustrating that the dynamics of viral coexistence are not always easily predictable, and underscores the importance of studying the underlying mechanisms at play. Full article

Microbiologically induced concrete corrosion (MICC) poses a severe challenge to the long-term durability of infrastructure, particularly in sewer networks and marine environments, which is driven by microbial metabolic activities that attack cement hydrates (Ca(OH)₂, C-S-H) mainly caused by biogenic sulfuric acid (from sulfur-oxidizing bacteria) or organic acids (from fungi), converting them into expansive gypsum and ettringite, and then cause cracking and spalling. This article reviews advances in mechanisms, key microorganisms, and protection strategies of MICC to enhance our understanding of MICC and provide a guideline for effective protection. The corrosion mechanisms differ by environment: sewers exhibit three-stage pH-driven succession, marine biofilms can either accelerate or inhibit corrosion, while fungi dominate in agricultural and historical settings. Core functional microorganisms involved in MICC include sulfur-oxidizing bacteria (SOB), sulfate-reducing bacteria (SRB), and acid-producing fungi (AF), following pH-dependent succession, while indicator microorganisms for protection efficacy include typical SOB, SRB, and AF that are involved in MICC, as well as general antimicrobial indicator strains (e.g., Escherichia coli and Staphylococcus aureus) which are used only to assess broad antimicrobial activity and do not represent MICC-specific resistance. Multi-scale deterioration proceeds from microstructural decalcification and pore coarsening to macroscopic mass loss and compressive strength reduction. Protection strategies are categorized into: (i) corrosion-resistant materials (e.g., calcium aluminate cement and alkali-activated materials), (ii) antimicrobial additives (e.g., nano-ZnO and Cu₂O), (iii) surface coatings (e.g., superhydrophobic coatings and electrodeposited Cu/Cu₂O layers), and (iv) ecological regulation. However, significant gaps remain between laboratory efficacy and field performance, highlighting the need for long-term validation, multi-scale characterization, intelligent responsive materials, eco-compatible protection systems, and standardized microbial exposure systems. Full article

This case study investigates the rapid through-wall perforation of newly installed hot-dip galvanized (HDG) fire sprinkler pipes in a coastal Mediterranean environment. Failure occurred along the internal waterline of horizontal sections within a short service period. Forensic analysis—comprising metallography, SEM, and EDS—identified a synergistic atmospheric–aqueous corrosion mechanism. Marine aerosol exposure during pre-service storage led to significant chloride enrichment and localized depletion of the 40–50 μm zinc coating, initiating early-stage pitting. Upon commissioning, stagnant water established oxygen concentration gradients and differential-aeration cells, driving localized anodic dissolution. Additionally, sulfate-reducing bacteria (SRB) contributed to accelerated degradation through microbiologically influenced corrosion (MIC), as suggested by sulfur-bearing tubercles. The findings demonstrate that standard galvanizing thickness alone does not ensure longevity in high-salinity environments if atmospheric “preconditioning” occurs. These results underscore the necessity of shielding internal pipe surfaces during storage and construction to prevent premature failure. This case study informs predictive maintenance and material selection for stagnant-water systems in coastal regions. Full article

We evaluated the antimicrobial and antioxidant capabilities of a bacteriocin purified from a recently identified marine Lactococcus lactis (L. lactis) NAN6399 strain, a lactic acid bacterium recovered from Mediterranean coastal waters near Alexandria, Egypt, and identified by combined API 50 CHL phenotypic profiling and 16S rRNA gene sequencing. Bacteriocin purification was achieved by sequential ammonium sulfate precipitation and reverse-phase high-performance liquid chromatography (RP-HPLC). The purified bioactive fraction had an approximate molecular weight of 20 kDa by SDS-PAGE and a 106-amino-acid N-terminal sequence that, upon BLAST alignment, returned 98.1% overall identity to the Lactococcin 972 family bacteriocin AAK06118.1 from L. lactis IL1403, with divergence confined exclusively to the terminal two C-terminal residues. This sequence is structurally and functionally distinct from canonical Lcn972 (L. lactis IPLA 972): the two peptides share an identical 25-residue signal peptide but diverge entirely in their mature bioactive domains, which exhibit only 9.1% sequence identity. Canonical Lcn972 operates through Lipid II-mediated septum disruption and inhibits only Lactococcus species; the NAN6399 peptide, correctly designated as a novel member of the Lcn972-like peptide family, demonstrated broad-spectrum antimicrobial efficacy against multiple indicator organisms (Staphylococcus aureus, Salmonella typhimurium, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Enterococcus faecalis), producing inhibition zones of up to 30 mm and minimum inhibitory concentration (MIC) values as low as 1.25 μg/mL against S. aureus. Antioxidant capacity was assessed using the DPPH radical scavenging assay, with the purified preparation achieving 73.14 ± 0.34% inhibition. Collectively, these data establish L. lactis NAN6399 as the producer of a bifunctional Lcn972-family bacteriocin with both antimicrobial and antioxidant potential, provide the first experimental characterization of the antimicrobial activity of this Lcn972-family branch, and highlight marine LAB as a productive reservoir for novel bioactive peptide discovery. Full article

Juglone (5-hydroxy-1,4-naphthalenedione), a natural compound derived from walnut husks, was investigated as a sustainable dual-function antibacterial agent and corrosion inhibitor for Q235 steel in sulfate-reducing bacteria (SRB)-containing seawater. Juglone was synthesized via an improved one-pot method, and its performance was evaluated through antibacterial assays, weight loss measurements, surface characterization (SEM, XPS, XRD), and electrochemical techniques (EIS, PDP). Juglone exhibited potent antibacterial activity against Desulfovibrio sp., with a minimum inhibitory concentration (MIC) of 40 mg/L. At 20 mg/L (0.5 MIC) and 40 mg/L (1 MIC), it effectively suppressed bacterial growth and metabolism, mitigating corrosion. At 80 mg/L (2 MIC), a dual-action mechanism was observed: strong antibacterial effect combined with chemical reaction with H₂S, a corrosive SRB metabolite, forming a protective thiol-containing film on the steel surface. This reduced the corrosion current density from 3.16 × 10⁻⁵ A/cm² to 7.94 × 10⁻⁷ A/cm², achieving an inhibition efficiency of 97.5%. Juglone represents a promising green alternative to conventional toxic antibacterial agents, aligning with circular economy principles. Full article

Oyster aquaculture offers promising opportunities for diversifying marine production in the Romanian Black Sea, where favorable environmental conditions and recent regulatory developments support shellfish farming. This study aimed to generate baseline data for the cultivation of the Pacific oyster, Magallana gigas, through an in situ experimental trial conducted off Mamaia Bay, Romania. A 50 m experimental long-line system was deployed at 13.5 m depth, and triploid oysters were cultured for one year at two depth horizons (3 m and 6 m). The growth performance, meat yield, Condition Index, microbiological quality, environmental parameters, and epibiotic communities were monitored monthly. Cultivation depth significantly influenced oyster growth, with individuals reared at 6 m consistently achieving a greater wet weight and shell length than those at 3 m. Growth rates peaked during spring, and meat yield values indicated good commercial quality. Environmental monitoring showed strong seasonal variability, with high summer temperatures and reduced dissolved oxygen associated with increased mortality. Microbiological analyses revealed higher bacterial loads during warm months. The Condition Index classified the oysters as generally “fine” to occasionally “special”. Overall, the results demonstrate that Black Sea conditions can support successful cultivation of M. gigas, although seasonal environmental stress and epibiosis require appropriate farm management. Full article

Freshwater scarcity is a major global issue faced by various regions, and the most common portable water sources globally are estuaries, canals, dams, lakes, and rivers. Existing water resources function as the best sinks for the frequent release of effluents from industrial and residential activities. This common practice often results in water pollution, a deterioration in marine biodiversity, and possible health risks for human populations. This study employed standard analytical methods in assessing the physicochemical and microbial characteristics of water samples collected from the Sundays River estuary in Eastern Cape Province (ECP), South Africa (SA). Microbiological assessment revealed that during the spring season, presumptive Escherichia coli (E. coli) colony counts were 1 cfu/100 mL, while total coliforms (TCs) and fecal coliforms (FCs) were recorded at 42.67 cfu/100 mL and 1 cfu/100 mL, respectively. In the summer season, fecal coliform (FC) counts reached 3.5 cfu/100 mL, while Enterococcus levels were higher, ranging up to 77.75 cfu/100 mL. Furthermore, the average standards of physicochemical parameters assessed in water obtained from both spring and summer seasons ranged as follows: pH (8.71–9.31), temperature (20.98–22.21 °C), turbidity (10–35.55 FNU), total alkalinity (22.25–94.00 mg/L), oxidation–reduction potential (ORP) (8.05–151.6 mV), electrical conductivity (EC) (13,915–40,260 uS/cm), salinity (8.07–25.78 psu), dissolved oxygen (DO) (6.79–7.39 mg/L), total dissolved solids (TDSs) (6960.6–20,125 mg/L), and biochemical oxygen demand (BOD) (0.11–2.94 mg/L). The levels of TDS, EC, turbidity, and salinity in the Sundays River estuary water exceeded the World Health Organization (WHO) guidelines of 2017, rendering the water unfit for even recreational purposes. Additionally, the bacterial levels identified in this study were above the values set by the South Africa Department of Water Affairs (SA-DWAF). The identified microorganisms are perceived as essential indicators of fecal contamination and have the potential to multiply in the environment. Possible pollution may be a result of various municipal effluents consistently discharged into the waterbody. Full article

The correlation between fouling-driven corrosion and magnetic Barkhausen noise (MBN) in AH36 naval steel was investigated under real Mediterranean seawater conditions over a 12-month immersion period. A custom-designed MBN analyzer was used to monitor four MBN parameters at monthly intervals: RMS amplitude (MBN_RMS), peak amplitude (MBN_peak), peak field position (MBN_{peak pos.}), and full width at half maximum (MBN_FWHM). Complementary characterization included pit morphology analysis, X-ray diffraction (XRD) of corrosion products, and quantitative biofouling community profiling. Three distinct MBN evolution regimes were identified, corresponding to active pitting (T₀–T₃), transitional oxide formation (T₃–T₆), and mature corrosion equilibrium (T₆–T₁₂). Over the full exposure period, MBN_RMS decreased by 50.4% and MBN_{peak pos.} increased by 83.3%, consistent with domain wall pinning at pit stress concentrations and electromagnetic shielding by paramagnetic corrosion product layers (γ-FeOOH, β-FeOOH, α-FeOOH). Pearson correlation analysis revealed near-unity relationships between MBN_RMS and maximum pit depth (r = −0.982, p < 0.01), supporting its potential use as a quantitative non-destructive indicator of corrosion severity under comparable exposure conditions. Biofouling, particularly sulfate-reducing bacteria (SRB)-dominated communities and biogenic iron sulfides (mackinawite, greigite), was identified as a statistically significant secondary correlate of MBN signal intensity (r = −0.944 vs. SRB fraction). A composite diagnostic threshold of (MBN_RMS × MBN_peak)/MBN_FWHM ≈ 0.015 effectively discriminated active pitting from passive rusting. These findings provide a physically grounded framework for multiparametric MBN analysis as a non-destructive condition monitoring tool, with the caveat that the reported correlations are descriptive and require independent validation before deployment in regulatory inspection protocols. Full article

Fish waste disposal poses significant environmental and economic challenges, limiting sustainability in the marine food industry. Hence, sustainable valorization strategies are needed to enhance resource recovery while minimizing waste. As an approach, this study aimed to evaluate the potential of converting chum salmon (Oncorhynchus keta) head (CSH) waste into a high-value peptone for microbiological applications. Various proteolytic enzymes were screened for CSH hydrolysis, among which Protamex achieved the highest hydrolysis and recovery rates. The resulting chum salmon head peptone (CSHP) exhibited favorable characteristics, including a low average molecular mass (557 Da) and a high amino nitrogen content (4.9%), outperforming commercial animal (AP) and vegetable (VP) peptones. To assess its biotechnological potential, CSHP was evaluated as a nitrogen source for recombinant protein production and supported higher expression of human superoxide dismutase (hSOD) and human growth hormone (hGH) in Escherichia coli BL21(DE3), compared with AP, VP, and Luria–Bertani (LB) media. Furthermore, life cycle assessment revealed a substantially lower carbon footprint for CSHP production than that of conventional peptone sources. These findings suggest that CSHP is a reliable and sustainable alternative to traditional peptones, offering both therapeutic and industrial applications while contributing to marine waste reduction and circular bioeconomy strategies. Full article