Malting and brewery wastewaters present environmental and economic challenges to the brewing industry due to their high organic loads and variable nutrient content, with chemical oxygen demand (COD) values ranging from 328 to 4500 mg/L and 910 to 8926 mg/L, respectively. Conventional treatment methods are limited by high energy consumption, sludge generation, and most importantly, a lack of resource valorisation. This review critically examines the role of extracellular polymeric substances (EPS) as key functional enablers in microalgae-based treatment of these effluents. Microalgal EPS enhance pollutant removal through biosorption mechanisms, facilitate biomass harvesting via natural self-flocculation, and represent valuable bioproducts with applications in the food, pharmaceutical, and environmental sectors. Integrating these functions within a circular biorefinery framework offers a holistic strategy that shifts traditional linear treatment methods toward circular resource utilisation pathways. Key technical and economic barriers to implementation are also identified in this review, including process scale-up, low-energy EPS extraction, and market development for EPS products.
The global coffee industry generates millions of tons of biomass residues annually, including pulp, husk, silverskin, and spent coffee grounds (SCG). These residues are often underutilized or discarded, despite being rich in bioactive compounds, dietary fiber, and carbonaceous materials. Their underutilization represents a missed opportunity for sustainable valorization and resource efficiency. This review synthesizes recent advances in chemical, biochemical, and thermochemical approaches for coffee residue valorization. Unlike prior reviews that typically address a single residue type or application domain, this work makes three integrative contributions: it covers the full spectrum of waste streams-pulp, husk, silverskin, and SCG-across the entire processing chain; it bridges agricultural valorization and nanotechnological/material-based applications within a unified evaluative framework; and it embeds these assessments within system-level considerations including cascading biorefinery design, life cycle assessment, techno-economic analysis, and digital optimization. Green extraction techniques, biotransformation processes, and advanced materials processing are critically evaluated across these dimensions. Coffee residues can be effectively converted into functional ingredients, biostimulants, bioplastics, and carbon-based nanomaterials, but the environmental and economic ranking of competing valorization routes is highly sensitive to feedstock moisture, transport logistics, product portfolio diversification, and grid carbon intensity. Cascading biorefinery models can achieve over 85
Climate change is intensifying environmental constraints in arid and semi-arid regions, where agricultural systems face recurrent drought, soil degradation, salinity, nutrient depletion, and increasing biotic pressures. While perennial crops are increasingly recognized for their role in stabilizing agroecosystems, the mechanistic integration of plant functional traits, microbial symbioses, and agroecological practices remains insufficiently addressed, particularly in Crassulacean Acid Metabolism (CAM) species. Opuntia ficus-indica, a widely cultivated CAM perennial, represents a relevant model for understanding plant resilience under water-limited conditions due to its high water-use efficiency and stress-adaptive traits. This review addresses this gap by synthesizing current knowledge through a structured framework encompassing: (i) functional traits of perennial and CAM plants, (ii) responses of O. ficus-indica to major abiotic and biotic stresses, (iii) agroecological practices for stress mitigation, and (iv) the role of plant growth-promoting rhizobacteria (PGPR) and arbuscular mycorrhizal fungi (AMF) in enhancing plant resilience. Mechanistically, agroecological practices such as intercropping, organic amendments, soil conservation, and optimized water management improve soil quality and resource availability, thereby supporting plant adaptive responses. In parallel, PGPR and AMF enhance stress tolerance through complementary processes, including improved nutrient acquisition, modulation of phytohormonal balance, osmotic adjustment, ion homeostasis, and activation of antioxidant defense systems. By integrating plant functional ecology, microbial interactions, and agroecological strategies, this review proposes a conceptual framework that positions O. ficus-indica as a model CAM system for improving stress resilience. Such integrative approaches are particularly relevant for optimizing the performance and sustainability of CAM crops under multiple environmental constraints in arid and semi-arid regions.
Microalgae-based systems are a versatile alternative for bioremediation due to their high photosynthetic efficiency and capacity to couple carbon capture with wastewater treatment and material circularity. However, large-scale application remains constrained by low biomass concentrations and high harvesting costs. These limitations have driven increased interest in microbial co-cultivation strategies inspired by natural ecosystems, where metabolic complementarity and cell aggregation enhance both biomass recovery and treatment performance. This review examines the state-of-the-art of fungal-microalgal symbiotic systems (FMSS) for wastewater bioremediation, with emphasis on emerging contaminants, such as heavy metals and antibiotics. FMSS improve pollutant removal through synergistic mechanisms operating at multiple levels, including extracellular adsorption mediated by extracellular polymeric substances (EPS), stress-induced EPS overproduction, and intracellular detoxification via glutathione-dependent redox transformations and enzymatic pathways. Fungal partners further enhance system performance by promoting biomass aggregation, improving harvesting efficiency, and enabling broader substrate degradation, while metabolic exchanges between partners stabilize photosynthesis, carbon assimilation, and stress resilience under toxic conditions. Recent developments in metabolic modulation, including strigolactone analogues, have further enhanced biomass productivity and removal efficiencies. Despite strong laboratory-scale performance, FMSS implementation is still limited by operational instability under high organic loads, biosafety concerns, and techno-economic constraints. Consequently, FMSS are most suitable as polishing units within wastewater treatment frameworks, aligning with circular bioeconomy principles through the recovery of high-value compounds within FMSS biomass. Overall, FMSS represent a multifunctional platform integrating contaminant removal and resource recovery at the interface of environmental remediation and sustainable biotechnology.
Anaerobic digestion (AD) of crop straw provides a promising route for converting abundant agricultural residues into methane and other value-added products. However, straw AD remains constrained by lignocellulosic recalcitrance, slow hydrolysis, uneven substrate accessibility, and the instability of multitrophic microbial interactions. This review synthesizes recent advances in straw AD by linking the major digestion stages, including hydrolysis, acidogenesis, acetogenesis, and methanogenesis, with the functional genes, microbial guilds, syntrophic interactions, and operational drivers that regulate process performance. Particular attention is given to straw-specific barriers, such as cellulose-hemicellulose-lignin associations, hydroxycinnamate cross-linking, particle heterogeneity, and limited enzyme–substrate contact. Multi-omics approaches are discussed as tools for connecting microbial composition, functional potential, gene expression, enzyme activity, and metabolic phenotypes, while their limitations in causal inference, data comparability, and functional validation are also examined. The review further highlights how omics-derived indicators, including hydrolytic enzyme modules, volatile fatty acid profiles, methanogenic markers, syntrophic partners, and stress-related functional signals, may support reactor diagnosis and operational control. Future progress in straw AD will depend on integrating genome-resolved multi-omics, targeted activity assays, perturbation experiments, and function-first cultivation to develop more reliable biomarkers, bioaugmentation strategies, and synthetic microbial communities for stable and predictable bioconversion.
Ammonia (NH3) emissions have become an increasingly significant issue in the livestock industry due to their negative impact on the environment and the emphasis on sustainable dairy production. A key principle in achieving source-oriented NH3 emission reduction is limiting urease activity in urine puddles. Optimizing floor management has been considered to be effective in limiting urease activity, thereby mitigating NH3 emissions. Given these considerations, this review synthesizes current knowledge by addressing four objectives: (1) describing the physicochemical mechanisms of NH3 release and its relationship to urease activity; (2) mapping the primary distribution of urease in dairy houses; (3) evaluating factors influencing urease activity, alongside methods to quantify their contributions; and (4) identifying effective floor management strategies to reduce urease activity and NH3 emissions. Urease, a ubiquitous microbial enzyme in nature, is primarily found in faeces and on floor surfaces within dairy houses. Based on Michaelis–Menten kinetics, the urease activity within a urine puddle is primarily governed by three key factors: maximum reaction rate, Michaelis constant, and the urea concentration in the puddle, which relate to the practical floor management strategies. Effective reduction of its activity in urine puddles requires integrated strategies combining optimized floor design, targeted disinfectant application, compatible manure handling practices, and scheduled cleaning protocols. A single-factor approach is insufficient to limit urease activity and achieve source-oriented NH3 emission reduction. This review provides a scientifically grounded and practical framework for implementing ammonia reduction strategies by diminishing urease activity in dairy housing systems.
Lignocellulosic biomass (LCB) is the world’s most abundant renewable carbon source, yet its potential to drive a circular bioeconomy remains largely untapped. Microbial electrochemical technologies (METs) offer a promising route for converting this complex feedstock into electricity or valuable chemicals. However, LCB-MET advancement is hindered by a fundamental challenge: LCB recalcitrance necessitates depolymerization, a process mismatched with the metabolic capabilities of most electroactive microorganisms (EAMs). While EAMs excel at oxidizing simple substrates, most lack the hydrolytic machinery to break down LCB, creating a critical performance bottleneck. Addressing this requires a multi-disciplinary approach. At the heart of the biological challenge lie two core paradigms,each drawing on microorganisms sourced from nature or artificially engineered: (i) specialized strains capable of both hydrolytic and electrogenic functions, or (ii) synthetic consortia establishing division of labor between fermentative microbes and EAMs. These strategies do not operate in a vacuum; their performance is constrained by materials and environment. To evaluate the progress and potential of these interdependent biological, material, and engineering strategies, this review examines the landscape of LCB utilization in METs. It synthesizes recent advances in coupling depolymerization with extracellular electron transfer, critically evaluate microbial players from pure strains and mixed communities to genetically modified organisms and synthetic consortia, and assesses the key operational parameters, challenges, and potential solutions that define this field. Moving beyond, the review provides graphic representations and statistical analyses of recent publications to establish quantitative performance benchmarks.
Accounting for the third-largest share of global nitrous oxide (N2O) emissions, paddy fields are a major source of this potent greenhouse gas, with emissions driven primarily by denitrification. N2O emissions may contribute to both ozone layer depletion and global warming, and pose substantial threats to public health and agricultural sustainability. Therefore, elucidating the microbial communities and their associated N2O emission pathways in paddy ecosystems is an urgent scientific priority. This manuscript identified the denitrifying microbial taxa responsible for N2O emissions across multiple taxonomic levels, from phylum to genus. Critically, while key genera such as Pseudomonas, Bacillus, and Paracoccus within the phyla Pseudomonadota and Actinomycetota are highlighted, these represented only the confirmed denitrifying members within their respective phyla. The underlying mechanisms of nitrogen loss mediated by the denitrifying microorganisms in paddy soils, along with the factors influencing nitrate removal and N2O flux, were carefully elucidated. A comparative analysis of both N2O emissions and denitrifying microbial community distribution in paddy fields across different countries and regions was presented. The relationships between specific microbial groups and N2O emission patterns were discussed. Based on these findings, this paper proposed targeted mitigation strategies aimed at suppressing the growth and activity of denitrifying microorganisms, including optimizing fertilizer application methods and improving irrigation technologies, to reduce N2O emissions. Future research directions in this field are also outlined. Collectively, this review intends to provide references for mitigating climate change and promoting sustainable agricultural development.
Anaerobic digestion (AD) is widely applied to stabilize wastewater sludge and recover energy, but it increasingly operates in the presence of emerging contaminants such as antibiotics, per- and polyfluoroalkyl substances (PFAS), and plastic particles including microplastics (MPs, < 5 mm) and nanoplastics (NPs, < 1 µm), collectively referred to as micro- and nano-plastics (MNPs) in the substrates. These highly persistent pollutants are routinely detected in wastewater treatment plants and often resist conventional removal, raising concerns about their long-term impacts on public health, ecosystems, and AD performance. On the other hand, full-scale digesters rarely operate under optimal conditions. Inhibitory levels of ammonia, sulfite, heavy metals, and toxic organics frequently induce systems into an “inhibited steady-state”, characterized by reduced biogas production and microbial activity, but without complete system failure. This review explores current knowledge on the fate, transformation, and removal of antibiotics, PFAS, and plastic particles (MPs and NPs) in AD, with a specific focus on these inhibited steady-state regimes. The impact of inhibition on microbial community structure and function, alterations in contaminant sorption and degradation pathways, and its influence on process stability are comprehensively discussed. Particular attention is given to prevention and mitigation strategies, including process optimization, pretreatment, the addition of sorbents and conductive materials, and combined treatment options. By explicitly accounting for realistic, non-ideal operating conditions, this work provides a framework for more accurate risk assessment and for designing robust, economically viable AD systems that can simultaneously manage complex contaminant mixtures while maintaining high treatment performance.
Critical elements underpin clean-energy, electronics and catalysis, yet conventional extraction from mine waste is chemically intensive, poorly selective, and increasingly infeasible as ore/waste grades decline. Bioleaching is gaining traction, but purification from leachates remains difficult, especially for chemically similar ions such as rare-earth elements (REE) and platinum group elements (PGE). Proteins offer an alternative: they recognise metals via programmable binding pockets and can be engineered for affinity, selectivity, and process compatibility. This review outlines coordination principles relevant to separation; compiles case studies for REE, gallium (Ga), rhodium (Rh) and arsenic (As); surveys discovery and engineering pipelines; compares protein deployment formats; and assesses challenges and routes to scale. Progress varies widely across elements. REE binding is comparatively mature: lanmodulin (LanM) and derivatives deliver high affinity and have enabled separation prototypes. Ga lags, with few binders reported to date. Rh remains poorly grounded in biology, with most evidence coming from interactions of synthetic organorhodium complexes with proteins rather than direct Rh-binders. The exception is As, where binding is well mapped, but mainly in the context of remediation rather than resource recovery. Scale is the main bottleneck: kilogram-scale production at acceptable cost is difficult, capacities often lag synthetic resins, and performance can decline in liquors with high ionic strength, competing ions, low pH, fouling, and repeated regeneration. Progress will require higher-capacity, longer-lived formats and expanded binder repertoires for underexamined elements such as Ga, Ge, Rh, Nb/Ta, In and Pd/Pt via speciation-aware discovery, engineering, and de novo or machine-learning design under mine-relevant conditions.
Concrete infrastructures function as anthropogenic biogeochemical ecosystems in which microbial communities interact with hydrated cement matrices across complex physicochemical gradients. While physical and chemical degradation pathways have been widely investigated, the contribution of environmentally derived microorganisms to long-term concrete performance remains comparatively under-integrated within durability frameworks. Microbial colonization, biofilm development, and metabolically driven transformations can substantially modify local pH, redox conditions, and mineral stability. In aggressive environments, such processes may accelerate deterioration through mechanisms such as microbially induced concrete corrosion (MICC), leading to matrix destabilization, reinforcement corrosion, and reduced service life. Conversely, controlled microbial activity offers emerging environmental biotechnological opportunities, including microbially induced calcium carbonate precipitation (MICP), bio-based self-healing, and microstructural refinement through biomineralization pathways. Recent advances in modelling highlight the potential to integrate microbial, chemical, and transport processes, although biological contributions remain poorly represented. This review synthesizes current knowledge on microbial-concrete interactions across diverse anthropogenic environments, including sewer networks, marine infrastructures, buildings and bridges, nuclear power plants, and deep geological repositories (DGR). Particular emphasis is placed on ecological selection processes, biogeochemical mechanisms driving material transformation, and biotechnological strategies aimed at monitoring, mitigating, or harnessing microbial activity within cementitious systems. By integrating environmental microbiology, geochemistry, materials science, and biotechnology, this work identifies unifying metabolic pathways, critical knowledge gaps, and future research directions for the development of more resilient and environmentally sustainable cement-based infrastructures.
Iron (Fe) oxides and natural organic matter (NOM) are ubiquitous and reactive components in various environmental systems, significantly influencing the fate and transport of contaminants. While Fe oxides typically sequester these contaminants, their reductive dissolution is a critical process that leads to remobilization, posing renewed environmental risks. This review synthesizes the current understanding of how NOM influences the reductive dissolution of Fe oxides. We summarize the mechanisms by which NOM drives this process: (1) acting as an electron donor and electron shuttle to accelerate reduction, (2) altering the morphology and size of Fe oxides, and (3) complexing with Fe(II) and Fe(III) to facilitate reduction. We further examine the biogeochemical dynamics of critical toxic oxyanions, specifically arsenic (As) and chromium (Cr), during the interaction of Fe oxides and NOM under reducing conditions. We highlight that NOM drives Fe oxide reduction and the concurrent reductive release of As, while directly reducing Cr, a process amplified by Fe oxides. Furthermore, NOM regulates the subsequent immobilization of As and Cr into secondary phases by retarding Fe oxide transformations. Together with competitive adsorption and complexation within the ternary system, these interconnected processes intricately control the biogeochemical cycling of As and Cr. Overall, this review provides a more profound understanding of Fe cycling and the associated fate of typical oxyanion contaminants in response to NOM, offering a theoretical basis for effective environmental remediation and management.
Natural cable bacteria and engineered bio-electrochemical snorkels enable centimeter-scale long-distance electron transfer (LDET) and have been shown to markedly enhance attenuation of polycyclic aromatic hydrocarbons (PAHs) in freshwater sediment. While the mechanisms of cable bacteria are well understood, those by which snorkel enhances attenuation of PAHs remain poorly defined. Because dissolved organic matter (DOM) binds the majority of PAHs in freshwater sediment, the transformation and eventual attenuation of PAHs is theoretically governed by DOM dynamics. Our previous studies preliminarily indicate that the snorkel alters DOM in its photo-chemical and electro-chemical characteristics. Inspired by those findings, this manuscript further reviews current knowledge on how DOM influences transformation of PAHs, summarizes the key DOM attributes involved in transformation of PAHs, analyzes how snorkel modulates these critical DOM attributes, and finally outlines four pathways by which snorkel enhances attenuation of PAHs. Although substantial work is required to validate these proposed pathways and to quantify their respective contributions, this mini-review significantly extends current limited studies including our own and provides the first in-depth analysis of how bacterial LDET enhances attenuation of PAHs, which can guide future sediment remediation strategies that leverage snorkel or other emerging electroactive bacteria-based technologies.
Wastewater treatment allows for water reuse and recycling yet produces waste by-products such as biosolids which require sustainable management. Biosolids have been repurposed for soil nutrient amendment in agricultural and land rehabilitation settings. However, biosolids contain microplastics and other micropollutants which negatively affect soil, animal, and human health and contaminate surrounding environments. The most prevalent microplastics in biosolids are synthetic microfibres made from polyester, polyethylene terephthalate (PET) and nylon that are released during clothes laundering and become concentrated in sewage sludges and biosolids during wastewater treatment. Microbes isolated from various environments, including plastic waste dumping sites, garbage dumps, soils, bodies of water, and marine environments, have demonstrated the ability to degrade polyester, PET and nylon, making them promising candidates for the biodegradation of these materials. This review discusses current literature on the microplastics and microbes present in biosolids, along with microbes documented to degrade plastics that are used in microfibre production. Additionally, recommendations are made to explore biosolids-associated microbes for microplastics biodegradation, aiming to minimise soil microplastic contamination to ensure the sustainable application of biosolids as well as alternative uses for biosolids.
Phosphite is a reduced inorganic phosphorus species increasingly reported in aquatic environments but often overlooked in conventional dissolved reactive phosphorus monitoring. Owing to its high solubility and redox lability, Phi can function as a transient, speciation-sensitive P pool and a substrate for microbial metabolism, thereby linking phosphorus availability to redox dynamics and potentially influencing eutrophication-relevant nutrient fluxes. Here, we synthesize current evidence on the occurrence, environmental partitioning, and transformation of Phi across various aquatic environments, and waters impacted by industrial wastewater and agricultural inputs. We first summarize recent methodological advances facilitating robust quantification of Phi at environmentally relevant concentrations. We then synthesize current knowledge of Phi biogeochemical cycling across freshwater systems, sediment and soil matrices, and marine environments, collating reported distribution patterns and disentangling the key environmental drivers governing Phi persistence and turnover dynamics. Furthermore, we delineate the core chemical and microbial transformation pathways of Phi in aquatic environments, encompassing anabolic phosphite oxidation, dissimilatory phosphite oxidation, and abiotic/engineered oxidation processes (e.g., UV/H2O2, Fenton-like reactions, PMS-based oxidation, and electrochemical methods). Additionally, we address the ecological and biogeochemical implications of Phi cycling for eutrophication mitigation, microbial community assembly, and aquatic ecosystem stability. Finally, we emphasized and elaborate on the priorities of future research endeavors. This work provides an in-depth and holistic understanding of the intricate phosphorus cycling processes, laying a robust scientific foundation for the design and implementation of efficient and sustainable phosphorus management strategies tailored to diverse aquatic environments.
Improved sewage sludge dewaterability saves costs in biosolids transport and disposal, making reliable dewaterability assessment essential for both research and full-scale process evaluation. However, laboratory-based indexes commonly used to predict dewatering performance often show limited correspondence with full-scale results. Nonetheless, indexes such as capillary suction time (CST), sedimentation and centrifugation methods, specific resistance to filtration (SRF), and mixed dead-end techniques show biases when trying to resemble full-scale results. In our present article, we pose that lack of predictability originates from overlooking all the phenomena involved in the dewatering process. Four critical phenomena are identified to occur during dewaterability: (1) mixing of sludge and conditioner; (2) suspension destabilisation; (3) flocs formation, and (4) compression and expression. By systematically evaluating widely used laboratory indexes this review shows that these methods capture only part of the dewatering process and generally fail to represent the compression and expression stages that ultimately determine the ultimate achievable solids concentration. The analysis highlights sludge compressibility as a critical factor limiting the predictive capacity of conventional indexes. Based on this synthesis, centrifugation, dead-end filtration, and combined centrifugation–filtration approaches are identified as more suitable methods for laboratory-scale assessment because they better represent the compression behaviour of sludge. The review provides a conceptual framework linking dewatering phenomena with experimental assessment methods, supporting the development of improved evaluation strategies and facilitating the testing of emerging, environmentally friendly conditioning technologies.
Lignocellulosic biomass is a renewable carbon source that could help replacing fossil carbon feedstocks which cause many ecological concerns. However, to improve its bioconversion, the complex microstructure and chemistry of biomass needs thorough characterization. Emerging techniques like Fluorescence Lifetime Imaging Microscopy are particularly promising and this review aims to cover all aspects related to the use of lifetime microscopy for lignocellulosic biomass analysis. First, the mechanisms involved in fluorescence emission and atomistic properties influencing fluorescence lifetime are detailed. Then the three main instrumentations of lifetime microscopy are compared and the decay fitting function of fluorescence lifetime is presented. Numerous examples exposing the relevance of fluorescence lifetime imaging microscopy for biomass analysis are provided. Lifetime microscopy allows for cellulose, hemicelluloses, and lignins differential localization and syringyl / guaiacyl lignin ratio mapping. Fluorescence lifetime imaging microscopy can also provide insights on the effects of pretreatment and hydrolysis on the microstructure and chemistry of lignocellulosic biomass. Additionally, lifetime microscopy can inform on growth conditions like geographical origin or reaction wood formation as a response to gravitropic perturbations. Also, Förster Resonance Energy Transfer, being able to explore lignocellulosic biomass’s interactions with molecular probes, can be based on fluorescence imaging as well. Finally, other fluorescence-lifetime-related techniques having the potential to be implemented on lignocellulosic biomass are discussed.
Phosphorus recovery and sustainable nutrient management are increasingly important for agricultural and industrial systems as global phosphate reserves decline. The disruption of the global phosphorus cycle, driven by fertilizer overuse and wastewater discharge, has intensified eutrophication and ecosystem degradation. In biological systems, inorganic phosphate fuels the very essence of life, forming the energetic basis of cellular function. However, fluctuating environmental phosphate conditions compel cells to store this element in the form of polyphosphate inside specialized organelles like acidocalcisomes. Polyphosphate homeostasis varies across microorganisms. Herein, by focusing on yeast and microalgae, this review follows the path of phosphate from its extracellular uptake by high and low affinity transporters (e.g., Pho89 and Pho90 yeast phosphate transporters; and PTA and PTC families of microalgal phosphate transporters) until its polymerization by Vacuolar Transporter Chaperone complex complex, which represents a functionally comparable polyphosphate synthesis mechanism in these two microbial taxa. Despite extensive research, a comparative overview linking molecular mechanisms to environmental bioprocess performance remains limited. Here, we bridge this gap by synthesizing mechanistic, physiological, and ecological insights to assess the potential of both groups as sustainable phosphorus recovery systems. This review synthesizes multi-omics analyses, structural studies, metabolic modeling approaches, and genome engineering strategies to advance understanding of microbial polyphosphate metabolism and its relevance for phosphorus recovery. Collectively, this review identifies key opportunities for leveraging microbial polyphosphate metabolism to advance environmentally resilient and resource-efficient phosphorus recovery technologies.
The escalating environmental cost of global plastic production is driven by a fundamental misalignment: the complexity of modern polymer chemistry has outpaced the capability of linear waste management infrastructure. Addressing this crisis requires moving beyond fragmented mechanical and thermal solutions to a fully integrated industrial framework that synchronises material innovation with biological discovery. This review articulates a strategic roadmap to transition from a linear disposal model to a robust bio-industrial circular economy, with a predominant focus on the deployment of emerging bio-catalytic and bio-hybrid processing systems. We distinguish between the dual goals of resource recovery (circularity) and safe mineralisation (environmental resilience). Four interdependent pillars essential for this transition are identified: (1) Material design, where “design for degradation” is embedded at the molecular level; (2) Bio-hybrid processing, which supersedes single-mode recycling by synergising biological selectivity with physicochemical throughput (e.g., chemo-biological and photochemical-biological coupling) to handle mixed waste streams; (3) Digital logistics, utilising the “Internet of materials” to enable high-resolution sorting and decentralised processing; and (4) Adaptive policy, where standards are co-developed to verify system compatibility and increased stakeholder engagement. A “paradigm shift” is necessary to align these domains. Only by integrating the material, the process, the data, and the policy can plastic waste be transformed from an environmental liability into a predictable, high-value bio-industrial resource.
Harmful algal blooms (HABs) are one of such unprecedented issues that significantly disturb both freshwater and seawater and have posed a severe risk to human health, ecological security, and socio-economic growth. The present review primarily emphases on the significant development on the extenuation of HABs using photocatalytic nano-architectonics. The sources and types of numerous algal toxins, their ecological influences, and health risk assessment are discussed. Further, the potential of various advanced functional photocatalytic nano-architectonics such as MOFs, TiO2-based metal composites, carbon nitrides, COFs, graphene-based materials, zeolitic imidazolate frameworks, porous coordination networks, hybrid composite materials involving self-assembled metal ions/clusters with bridging organic ligands, biochar, etc., for HABs inhibition is explored. Furthermore, the plausible mechanisms of photocatalysts for the obliteration of HAB cells, along with numerous factors affecting the photocatalytic algal inactivation, are also covered. Finally, the review summarizes the discussion on the limitations, challenges, future perspectives, and solutions for further research in this research area.
