Tetracycline (TC) and nitrate (NO-N) co-contamination poses significant threats to aquatic ecosystems. In this study, an effective strain, identified as Paracoccus denitrificans XW1, was isolated and immobilized on wheat straw biochar for simultaneous TC and NO-N removal. Results demonstrated a significant enhancement in TC and NO-N removal by biochar-immobilized XW1 (IB), with IB exhibiting 1.29 to 8.90-fold greater TC removal and 1.03 to 2.57-fold higher NO-N removal than free XW1 cells (FB) across varied environmental conditions. Mechanistic studies revealed that the enhanced TC removal was predominantly adsorption-dependent, whereas NO-N elimination was primarily driven by biochar-facilitated biodegradation. Over five reuse cycles, IB sustained enhanced NO-N removal (38.56% to 94.76%) but exhibited gradual TC decline (67.22% to 12.80%) from adsorption saturation, while FB rapidly lost TC degradation capacity within two cycles. Biochar promoted antioxidant enzyme production to mitigate oxidative stress induced by TC. Meanwhile, biochar stimulated extracellular polymeric substances (EPS) secretion, particularly humic acid-like substances, which concurrently enhanced TC adsorption and facilitated denitrification. Transcriptomics analyses further revealed that biochar upregulated genes associated with the tricarboxylic acid (TCA) cycle, ATP-binding cassette (ABC) transporters, and quorum sensing in XW1, consequently enhancing energy metabolism, enzymatic detoxification, and bacterial cooperation. This synergy enabled the efficient simultaneous bioremediation of TC and NO-N. This work provides a sustainable biochar-microbe agent for complex water remediation.

The production of epsilon-poly-l-lysine (ε-PL) in submerged fermentation (SmF) exhibits defects of high energy consumption, excessive wastewater production, and inefficient oxygen transfer. To address these challenges, we developed an efficient ε-PL production method based on a novel solid-state fermentation (SSF) strategy using lignocellulosic hydrolysates as substrates and zeolites as solid carriers. The maximum ε-PL titer was found to be 47.6 g/L with spores inoculation at an initial pH of 6.5 and a 90 % medium saturation rate after 7 days of cultivation using an atomizing feeding system, representing a 1.88-fold increase of ε-PL productivity over conventional SmF. The increase in production can be attributed to elevated transcription of key genes, enhanced enzyme activity, increased energy metabolism, and enriched precursor pools, which were facilitated by direct oxygen transfer to cells, in situ removal of ε-PL and inhibitors, and reduced NH toxicity. This SSF approach offers a novel method for industrial-scale ε-PL biosynthesis.

The development of microalgae-based biofuels has long been a research focus for achieving green and sustainable development. Chinese medicine residues, an abundant organic waste rich in cellulose, hemicellulose, lignin, proteins, polysaccharides, and microminerals, offer scalable feedstock. Here, their hydrolysate (HCMR) was used as an additional nutrient source for cultivating oil-producing algae. The hydrolysate promotes the growth and productivity of oil-producing algae such as Chlorococcum sp., Tribonema aequale, and Scenedesmus sp., while also indicating its feasibility for scaling up Scenedesmus sp. cultivation. The HCMR addition increased biomass by 1.58-fold and fatty‑acid content by 1.27‑fold relative to BG11 medium. Analysis of the fatty acid composition in Scenedesmus sp. confirmed that the addition of hydrolysate from Chinese medicine residues significantly increased the proportions of high-quality fatty acids, including palmitoleic acid (C16:1) and oleic acid (C18:1), while reducing the proportions of linoleic acid (C18:2) and α-linolenic acid (C18:3), thereby improving the cetane number and oxidative stability of the biodiesel. Metabolomics analysis reveals potential regulatory pathways by which HCMR enhances lipid accumulation in Scenedesmus sp., implicating transamination in glutamate metabolism and offering a sustainable route for utilizing similar organic waste as an additional source of nutrients in oil-producing microalgae cultivation.

The cellulolytic system of Trichoderma reesei depends on β-glucosidases as central enzymes completing biomass hydrolysis and generating inducers such as sophorose. Three β-glucosidases from Aspergillus clavatus (AC), Penicillium oxalicum (PO) and Talaromyces stipitatus (TS) were expressed in Komagataella phaffii and characterized for parameters relevant to biomass conversion and inducer formation. PO and TS showed higher thermostability between 60 and 70 °C, whereas AC was inactivated above 50 °C. All variants were glucose inhibited, with AC least affected (K = 8.4 mM), followed by PO (K = 6 mM) and TS (K = 2.3 mM). Supplementation of Celluclast® with TS increased glucose release from cellulose and wheat straw and reached levels comparable to Cellic®CTec2 on wheat straw after 24 h. All enzymes catalyzed condensation reactions and produced up to 55 g/L disaccharides, with TS yielding the highest sophorose titers at 700 g/L glucose. Induction performance was assessed using T.reesei RUT-C30 cultivated with glucose, a TS derived disaccharide solution or steam-ex wheat straw hydrolysate. For each enzyme class, the highest activity across all conditions was defined as 100 %. The disaccharide solution generated the strongest cellulase response, while glucose yielded only 26 % BGL and 20 % CBH1 activity relative to these maxima, and hydrolysates produced intermediate levels of 65 % BGL and 24 % CBH1 activity while concurrently generating the highest hemicellulolytic activities, set to 100 %. Proteomics confirmed that the disaccharide solution upregulated core cellulases (EGL1 + 2.80, CBH1 + 1.66, EGL5 + 3.16), whereas hydrolysates enriched CBH2 (-2.02), GH11 xylanases (-3.27) and GH3 β-xylosidases (-6.45, -2.49).

In this study, we employ big-data analytics to perform a large-scale normalized comparison of microbial communities across varying influent characteristics, offering new insights into the community structure and functional responses of the anaerobic ammonium oxidation (anammox) process. We compiled 708 16S rRNA gene sequencing datasets of anammox-related consortia under five culturing conditions: natural environments, clean substrate, heavy metals (HMs) exposure, organics-amended medium, and antibiotic stress. Natural consortia exhibited the highest microbial diversity, whereas all artificially enriched consortia showed a marked simplification of community structure. Network analysis showed HMs/antibiotics sparsified microbial networks, weakening interspecies links; AnAOB homogenized under both stresses (Candidatus Kuenenia dominance) but shifted to Candidatus Brocadia under organics. By large-scale normalized analysis systematically characterizing the microbial community structures and core taxa variations under distinct feed regimes-particularly those of nitrogen-transformation groups-this study provides new insights into the ecological resilience and adaptability of anammox-related communities.

Per- or polyfluoroalkyl compounds (PFASs) are recognized as emerging contaminant, with perfluorooctane sulfonate (PFOS) being one of the most extensively utilized PFASs due to its great chemical stability. However, knowledge of the bio-chemical behavior, the toxicity of PFOS and its mechanisms of interfacial binding to microorganisms remain inadequately validated. In this study, the biotoxicity of PFOS and its molecular interfacial adsorption mechanism in anaerobic digestion were investigated. The results showed that the tightly bound EPS (TB-EPS) of anaerobic microorganisms could defend against the biotoxicity of PFOS to some extent by physical adsorption and chemical binding, the exposure to PFOS might produce a greater disturbance to methanogenic archaea. With the increase of PFOS, acid-producing bacteria (APB) and methanogenic archaea showed different resistance to PFOS, suppressing cumulative methane production by up to 91.64 %. On the contrary, APBs were more tolerant, and fatty acids accumulated up to 2194.27 mg/L. Metagenomics analysis further confirmed that functional genes associated with fatty acid biosynthesis (fas, FAS2, fabK, etc.) were significantly enriched (approximately 85.29 %) whereas the relative abundance of genes associated with methanogenesis (acs, comA, mcrB, etc.) were decreased (up to 65.96 %). Molecular docking results suggested a potential route for PFOS cellular entry, as it was observed to bind to the substrate-binding protein of the ATP-binding cassette (ABC) transporter and interact with key functional enzymes, which led to the inhibition of methanogens. This study provides novel insights into the molecular blocking mechanism by which PFOS disrupts carbon metabolic flux through the selective inhibition of methanogenic archaea, rather than through a general suppression of acidogenic bacteria.

The aim of this study was to investigate the mechanisms of in situ-synthesized iron sulfide nanoparticles (bio-FeS NPs) on the dissemination of antibiotic resistance genes (ARGs) in anaerobic microbial consortia. The absolute abundance of plasmid RP4-associated extracellular ARGs (eARGs) decreased by more than 10 copies/ng DNA in the anaerobic consortia containing in situ-formed bio-FeS NPs (AnBR-FeS NPs). Mechanistic analysis revealed that the inhibitory effect was related to the absence of a significant correlation between functional bacteria such as Nitratidesulfovibrio in AnBR-FeS NPs and Escherichia carrying the RP4 plasmid, as well as a 2.21-fold increase in calcium/magnesium adenosine triphosphatase and a 1.86-fold reduction in reactive oxygen species levels. Notably, co-occurrence analysis indicated that bio-FeS NPs preferentially maintained cellular homeostasis, reducing the dependence of ARG propagation on mobile genetic elements. This study provides new insights into the role of in situ nanominerals in suppressing ARG dissemination in anaerobic wastewater treatment systems.

The valorization of biodegradable plastics into high-value chemicals offers a sustainable pathway for plastic waste management. In this study, catalytic pyrolysis of poly(3-hydroxybutyrate) (PHB), a representative bioplastic, was systematically investigated over ZSM-5 zeolites with varying degrees of mesoporosity, aiming to maximize the BTEX yield. Catalyst characterization confirmed that mesopore introduction increased external surface area and accessibility of acid sites, while relatively reducing strong Brønsted acidity. Catalytic performance was evaluated, as well as the effects of different pyrolysis atmospheres (N, CO, CH) and catalyst-to-feed (C/F) ratios (1/10, 1/6, 1/3). Compared with non-catalytic pyrolysis, ZSM-5 significantly reduced oxygenates in the oil and promoted the formation of aromatic hydrocarbons. Among the mesoporous catalysts, MEHZ-1 delivered the highest selectivity, producing 56.44 % BTEX (benzene, toluene, ethylbenzene, and xylenes) in N atmosphere. Under CH co-feeding, MEHZ-1 achieved a further increase to 68.20 % BTEX, accompanied by a dramatic decrease in oxygenates from 33.10 % to 23.18 % compared to N atmosphere. Gas and oil analysis revealed that the mesoporous MEHZ-1 facilitated deoxygenation, mainly decarboxylation, and propene oligomerization that contributes to generating aromatics. Increasing the C/F ratio also enriched BTEX at the expense of oxygenates. Overall, the synergy of mesoporosity and optimized Brønsted and Lewis acidity in MEHZ-1, combined with CH, most effectively promoted aromatic hydrocarbon production. These findings highlight the potential of tailored mesoporous zeolites for efficient bioplastic upgrading into valuable aromatics, supporting sustainable chemical recycling within a circular economy framework.

Azithromycin (AZ), a broad-spectrum antibiotic, is commonly found in aquatic habitats. This study investigated two microalgae-microbial fuel cell (m-MFC) configurations, A-AZ-MFC (AZ in the anode) and C-AZ-MFC (AZ in the cathode), which were run in fed-batch mode under open- and closed-circuit conditions (10-200 mg/L AZ). AZ removal increased from 43 % in an open circuit to 83 % when the circuit was closed in A-AZ-MFC and from 68 % to 84 % in C-AZ-MFC. While both A-AZ-MFC and C-AZ-MFC achieved comparable AZ degradation (83-84 %), A-AZ-MFC demonstrated superior electrochemical output (Power density: 275 mW/m; Net energy recovery: 0.11 kWh/kg COD; Coulombic efficiency: 26 %) and higher microbial tolerance (IC = 77.02 mg/L), indicating effective electron transfer and steady biofilm activity. Both designs achieved successful detoxification, as evidenced by comparable transformation product profiles and lower effluent toxicity. These findings demonstrate m-MFCs, especially anode-optimized systems, as sustainable platforms for the removal of antibiotics and the production of bioenergy.

The current study developed a mycelium lignocellulosic biocomposite (MLB) from rice husk and tangerine peel and evaluated its potential for resource recovery through anaerobic digestion (AD) under different temperatures. The MLB was cultivated with G. lucidum without the use of synthetic binders. Several substrate-to-water ratios were examined, with a 1:2 ratio yielding the most favorable material properties. After production, the MLB was subjected to AD at 36 °C and 55 °C using two operational strategies: mono-digestion and co-digestion with sewage sludge (SL). Under mesophilic co-digestion, methane yields reached 284 mL CH/g∙VS, accompanied by efficient conversion of volatile fatty acids (VFAs) to methane. However, thermophilic operation enriched heat-adapted consortia but led to VFA accumulation and reduced methane production. These results highlight a substrate-dependent temperature effect: thermophilic conditions enhance sludge biodegradation but do not sufficiently overcome the recalcitrance of MLB, whereas mesophilic co-digestion promotes syntrophic interactions and achieves higher conversion to methane.

The Kraft pulping industry produces significant amounts of lignin-rich black liquor, a largely underutilized renewable resource. We report a scalable method to synthesize lignin-derived graphene quantum dots from raw eucalyptus kraft black liquor (EL-GQDs) through sequential acid oxidation and hydrothermal carbonization. Structural and surface analyses confirm the formation of graphitic nanostructures with oxygen- and nitrogen-rich functional groups, exhibiting strong visible fluorescence, good aqueous dispersibility, and high photostability, with uniform morphology and lattice fringes characteristic of crystalline GQDs. The bioimaging potential of EL-GQDs was tested using Nile tilapia testicular cells in vitro and in vivo, achieving efficient cell labeling with low toxicity. Labeled cells remained viable and localized within the gonads up to 30 days post-transplantation. These results demonstrate that EL-GQDs are biocompatible, photostable, and sustainable nanoprobes suitable for long-term cell tracking in aquatic reproductive research. Further studies on uptake pathways, cross-species application, and long-term biosafety are needed to advance this technology.

2,3-Butanediol, an important platform chemical, possesses extensive applications in chemical engineering, pharmaceuticals, and materials science. To address the challenges of resource depletion and environmental impact associated with conventional petroleum-based synthesis, this study focuses on the sustainable production of 2,3-BDO via microbial fermentation. Aureobasidium melanogenum TSYW-58 was employed as the chassis for metabolic engineering. In previous work, genes responsible for the biosynthesis of pullulan, polymalic acid, melanin, and liamocin were deleted, yielding strain PPLM-8, characterized by high gluconic acid titer and reduced by-product formation. Building upon this platform, genes encoding α-acetolactate synthase and α-acetolactate decarboxylase from Bacillus subtilis were heterologously expressed, along with the endogenous butanediol dehydrogenase, leading to the successful construction of strain P8AC-4. This strain is capable of efficient 2,3-BDO production with minimal by-products. Shake-flask fermentation yielded 43.21 ± 1.23 g/L of 2,3-BDO, with a stereoisomer composition of 77.07 % meso- and 22.93 % (R,R)-isomer. Fermentation kinetic analysis in a 5 L bioreactor revealed that 2,3-BDO biosynthesis is tightly coupled with the logarithmic growth phase of the microorganism. By leveraging this metabolic trait, growth-inhibiting components present in untreated straw hydrolysate and molasses were employed to modulate fungal growth rates. Notably, cultivation with untreated molasses as the carbon source effectively extended the product synthesis phase, achieving a 2,3-BDO concentration of 110.37 ± 4.43 g/L in batch culture, representing a 155.42 % increase compared to that obtained with the glucose-based medium. These findings offer an efficient and cost-effective biomanufacturing strategy for the industrial-scale production of 2,3-BDO, contributing to the advancement of sustainable chemical synthesis.

Biomass pyrolysis is a promising thermochemical pathway for producing renewable fuels and chemicals, yet its optimization remains challenging due to the complex interactions among feedstock properties, operating conditions, and reactor configurations. Artificial intelligence (AI), particularly machine learning (ML), is emerging as a powerful tool to improve predictive modelling and mechanistic understanding of pyrolysis. This review critically examines four pyrolysis regimes (slow, intermediate, fast, and flash) and advanced strategies such as co-pyrolysis, catalytic enhancement, and microwave heating, before discussing how ML algorithms are reshaping data-driven modelling. Supervised models, including random forests (RF), extreme gradient boosting (XGBoost), and artificial neural networks (ANNs), have achieved high accuracy in predicting product yields, while unsupervised and reinforcement learning approaches reveal hidden trends and enable adaptive process control. Furthermore, explainable AI frameworks (XAI), such as Shapley Additive Explanations (SHAP) and partial dependence plots (PDP), provide mechanistic insights that bridge data with reaction pathways. By combining AI with reactor optimization and mechanistic explanation, this field offers a pathway to efficient and scalable pyrolysis systems. Finally, we outline research gaps and future directions, emphasising the need for interpretable and generalisable models that can guide large-scale deployment.

Ammonia-oxidizing archaea (AOA) in wastewater systems remain underexplored for their roles in nitrogen removal and nitrous oxide (NO) production. This study investigated ammonia oxidation and NO production by a wastewater-derived AOA enrichment (>42 % Candidatus Nitrosocosmicus, cultivated using antibiotics) under varying oxygen and substrate (organic carbon, nitrite) availabilities. NO production was first precisely quantified by retracting the portion (49-56 %) consumed by endogenous denitrification. Biomass-specific NO production (5.08 × 10 to 2.38 × 10 μmol N/10 copies, 0.4-21 % O) were 90-97 % lower than that of ammonia-oxidizing bacteria. The negative correlation between NO production and oxygen in AOA was driven by hybrid formation and abiotic hydroxylamine oxidation. Candidatus Nitrosocosmicus was inhibited by exogenous nitrite as free nitrous acid at 0.11-0.15 μM, whereas organic carbon alleviated inhibition via heterotrophic nitrite reduction, elevating NO emission factors to 0.77-1.09 % in ammonium- and nitrite-amended cultures (0.4-4.2 % O). The findings will help updating NO quantitative statistics and developing carbon-neutral nitrogen removal process.

As a core platform molecule in biomass conversion, furfural requires accurate prediction of its pyrolysis behavior for the practical application of furan-based alternative fuels. However, existing pyrolysis models are inadequate for describing its thermal decomposition, as many kinetic parameters estimated via the analogical method introduce significant uncertainty. This study employs quantum chemical calculations based on Transition State Theory (TST) and Rice Ramsperger Kassel Marcus (RRKM) theory to systematically investigate hydrogen-abstraction, hydrogen-addition, and unimolecular reactions in furfural pyrolysis, with reaction rates calculated over 500-2500 K. Results show that the analogical method overestimates the rates of hydrogen-abstraction and hydrogen-addition reactions at low temperatures. Simulation validation was conducted using a Perfectly Stirred Reactor (PSR). Mole fraction comparison analysis confirms the improved model more accurately reproduces the variation trends and magnitudes of experimental data. Sensitivity analysis indicates that the modified model corrects the potential overestimation of the contribution of addition pathways in the original model.

Greenhouse gases (GHGs) emission from composting was a major concern, however it is still unpredictable due to the complex characteristics of organic waste and differentiated composting conditions. In order to raise the predictability of GHGs emissions from composting, 501 filed-monitoring based datasets of methane and nitrous oxide effluxes and five influential factors were collected from seven decentralized composting sites in China, and then explainable machine learning method was applied for predicting their GHGs emissions. It was found that methane and nitrous oxide effluxes varied between 2.57 × 10∼32.41 mg (CH)·m·min and 1.98 × 10∼2.27 mg(NO)·m·min, while Adapt Boosting and Gradient Boosting model can achieve the highest predicting accuracy. Pile temperature and C/N ratio were the key drivers for methane and nitrous oxide emissions. The lifecycle GHGs emission factors suggested herein were 4.5 %∼15.0 % of those in IPCC average defaults. This work provides an innovative approach to understand and control GHGs emission from composting.

Stress-resistant heterotrophic nitrification-aerobic denitrification (HN-AD) strains can efficiently remove nitrogen from wastewater with high ammonia, high acidity, high salinity, low temperature, and heavy metals. This study systematically reviews the nitrogen removal characteristics, application performance, metabolic mechanisms and future prospects of stress-resistant HN-AD strains. As a result, (1) Stress-resistant HN-AD strains have gained growing interest, especially multi-stress-resistant strains. (2) HN-AD genera Acinetobacter (resistant to high ammonia and low temperature) and Pseudomonas (resistant to high ammonia and salinity) can improve bioreactors' tolerance, requiring further engineering applications. (3) Stress-resistant HN-AD strains resist stress via three mechanisms: upregulating nitrogen metabolism genes, enhancing membrane transport, and modulating signaling molecules, which results in enhanced bioreactor performance. (4) Screening multi-stress-resistant strains should remain a priority, focusing on large-scale application, conductive material immobilization, colonization and genetic mechanism verification, and life cycle/economic analysis. This study provides vital references for HN-AD strain screening and applications under extreme conditions.

Ternary deep eutectic solvents (tDES) are tunable, multifunctional green solvents that offer clearer advantages over binary deep eutectic solvents (bDES) for selective lignocellulosic biomass fractionation. By adding a third component, tDES allow better control of polarity, acidity, and viscosity, which improves delignification, hemicellulose removal, and lignin stabilization. Key factors include reducing lignin condensation using polyols and Lewis acids, which stabilize reactive lignin intermediates, undesired CC bond formation and repolymerization during fractionation. This helps preserve β-O-4 linkages and yields lighter, lower-molecular-weight lignin that is more suitable for downstream depolymerization and valorization. Moreover, downstream routes to lignin nanoparticles and catalytic depolymerization are outlined, along with emerging "polymerizable" tDES or eutectogels that couple pretreatment with the fabrication of ion-conducting, 3D-printable soft materials. Finally, sustainability is assessed through recyclability, solvent recovery, toxicity, and life-cycle metrics, although challenges remain in high-viscosity mass transfer, component screening and standards, potential metal salt ecotoxicity, and scale-up and techno-economics. This review will inspire more investigation into the use of tDESs towards a sustainable future.

A study was carried out on the sequential treatment of young high-strength landfill leachate using an aluminium electrode in a batch electrochemical cell reactor as a pretreatment, followed by a packed-bed upflow anaerobic filter (PBUAF) as a treatment method. Two landfill-simulating reactors, made of iron sheets having sizes of 1 m × 1 m × 1.1 m (Length × Width × Height), were operated under varying hydrological conditions where one was operated without rain (S1) and another with simulated rain (S2). The reactors were loaded with 450 kg of municipal solid waste, comprised of 51 % wet and 49 % dry fractions, typical of Indian waste. Electrocoagulation was performed as a pretreatment process with aluminium electrodes for 10 min, and it achieved 40-50 % removal efficiency, which preconditioned the leachate to be treated further by biological means. The pretreated leachate, supplemented with de-oiled rice bran (DORB), was introduced to the PBUAF. The PBUAF was able to achieve substantial pollutant removal, attaining 93.9 % of Chemical Oxygen Demand (COD), 97.46 % of Total Organic Carbon (TOC), and 94.24 % of Total Kjeldahl Nitrogen (TKN), in addition to other recalcitrant pollutants at an optimized organic loading rate (OLR) of 5.107 g COD/L/day and a hydraulic retention time of 8 days. Kinetic analysis indicated that the Stover-Kincannon and Monod models were highly consistent with experimental data. The Electrocoagulation-PBUAF hybrid system effectively removed persistent organic pollutants, including naphthalene, phenols, benzene derivatives, halogenated compounds, alcohols, and phthalates, demonstrating its capacity to treat both prevalent and resistant pollutants efficiently.

The specific recognition capability of Candida rugosa lipase presents a green approach for separating conjugated linoleic acid (CLA) isomers. However, its limited selectivity and poor operational stability have impeded its industrial applications. This study established a novel system based on mesoporous silica (MS)-immobilized lipase for selective esterification in a non-aqueous phase, enabling the efficient enrichment of CLA isomers. By functionalizing the MS surface and optimizing immobilization parameters, a lipase loading capacity of 89.61 ± 1.21 mg·g was achieved. Subsequent optimization of the esterification conditions significantly enhanced the catalytic efficiency and selectivity of the immobilized lipase. A two-stage selective esterification process, with ethanol as the acyl acceptor, produced c9, t11-CLA with a relative purity of 87.05 % (33.02 % recovery) and t10, c12-CLA with a relative purity of 89.83 % (35.96 % recovery). This study provides a sustainable and scalable approach for the green production of high-value CLA isomers, with potential applications in functional foods and nutritional health products.

Leachate produced during the composting of the organic fraction of municipal solid waste (OFMSW) is highly concentrated and acidic (chemical oxygen demand (COD) -125 g/L, pH 3-5). Its recalcitrant nature necessitates long hydraulic retention times for effective digestion, which, in turn, leads to high organic loads and, consequently, large reactor footprints. This study evaluated the treatment performance, bioenergy potential, and microbial ecology of the Anaerobic Biomass Biofilm Reactor (ABBR) for ultra-high strength leachate treatment. The reactor employed lignocellulosic wastes such as coir, ridge gourd, and dried acacia leaves as natural biofilm supports. Operated over 180 days with a gradually increasing organic loading rate from 1.1 to 11.2 kg COD/m/d, the reactor achieved 92.9 % COD removal and a methane yield of 0.357 NL/g COD removed at the maximum loading rate. Moreover, the reactor also exhibited exceptionally high space utilization efficiency (3.5-4 L CH/L/d), highlighting its enhanced volumetric productivity and effectiveness in treating high-strength leachate. Metagenomic analysis revealed a diverse microbial community, with Methanospirillum (3 %) and Methanosaeta (2.6 %) identified as dominant archaea contributing to methanogenesis. The high moisture content of OFMSW, coupled with tropical climatic conditions, leads to rapid fermentation and the generation of large volumes of leachate. Therefore, the ABBR represents a sustainable and high-rate alternative to conventional anaerobic systems, enabling efficient leachate treatment and enhanced bioenergy recovery in windrow composting facilities.