Biodegradation Performance Research Articles

Design improvements to enhance mechanical performance of a locking compression plate as a biodegradable implant plate: a finite element analysis

Mg alloy is one of the most suitable biodegradable materials for making modern LCP. This is due to the osseointegration property, low elastic modulus, the presence in the human bone, and the excellent biodegradable nature. But it lacks much-needed strength compared to conventional (Ti, SS alloys) implants due to low strength of biodegradable (Mg, Zn alloys) materials. The problem can be solved by either biodegradable material development or by design improvement of existing LCP. Improving the design is a better way to improve the LCP. This paper aims to improve the design of existing LCP through the addition of features and their implications by analysing the stress distribution across the plates for improved biodegradable implant mechanical performance. Various designs have been developed and each has certain advantages over conventional LCP which ACT and 4PBT have been demonstrated via the FEM. They are best suited for femur bone fracture treatment replacing conventional metal alloys LCP. The CTLCP, SLCP, and SELCP have improved performance at stress concentration regions while STLCP especially has 36.74% less stress generation than conventional LCP along with excellent biodegradable performance. The designs are discussed in detail to analyse the effect of added features in conventional LCP.

Biodegradation of insecticides: oligonucleotide insecticides and double-stranded RNA biocontrols paving the way for eco-innovation

Each new class of insecticides that emerged during the development of plant protection gradually found the most suitable group of insect pests for application. At the same time, for each individual insecticide, a balance was sought between its effectiveness, on the one hand, and its safety for non-target organisms and the ecosystem as a whole, on the other hand. Neonicotinoids, diamides and pyrethroids, as effective control agents, dominate the insecticide market, but do not have outstanding performance in selectivity and biodegradation. The biodegradation of insecticides is one of the most important indicators, representing what will be said about the hidden costs for the resulting harvest paid by the environment and human health. Oligonucleotide insecticides (contact unmodified antisense DNA (CUAD) biotechnology, or ‘genetic zipper’ method) and RNA biocontrols (double-stranded RNA technology) as natural polymers and the next-generation classes of insecticides possess unique characteristics in fast biodegradation and high selectivity in action. While current chemical insecticides require days, months and even years for biodegradation by bacteria and fungi, oligonucleotide insecticides and RNA biocontrols are substantially biodegraded within hours in the presence of nucleases. Nucleic acid-based insecticides have the potential to complement the existing insecticide market and set an eco-precedent for crop protection products where the effectiveness of the insecticide will be determined by its safety for non-target organisms, and other factors being equal, the choice of a particular control agent will be determined by its biodegradability. It should be noted that not a single class of insecticides that once appeared has completely disappeared; rather, it has occupied its niche, gradually declining under the pressure of new classes of insecticides. At the same time, the common trend in plant protection is towards use of insecticides with higher biodegradability, which gives hope for a safer future of the planet.

Valorization of paper-mill sludge laden with 2-chlorotoluene using hydroxyapatite@biochar nanocomposite to enrich methanogenic community: A techno-economic approach

While several studies have investigated the anaerobic digestion of paper-mill sludge (PMS), this technology suffers from nutrient insufficiency, inhibition by aromatic compounds, and low bio-CH4 yield. Hence, PMS was anaerobically co-digested with chicken manure (CM) and supplemented by hydroxyapatite@biochar (HAP@BC) nanocomposite for enhancing 2-chlorotoluene degradation and enriching the methanogenic archaea. Multiple continuous stirred tank reactors (CSTRs) were operated at 12.6 h hydraulic retention time (HRT), using PMS (R1), CM (R2), PMS + CM (R3), PMS + CM+100 mg HAP/L (R4), and PMS + CM+100 mg HAP@BC/L (R5). The maximum bio-CH4 yield of 147.5 ± 9.1 mL/g COD and 2-chlorotoluene removal of 91.2 ± 6.8 % were obtained from R5, experiencing a sufficient C/N ratio of 14.7 and the highest activities of acidogenesis (42.0 %), acetogenesis (37.9 %), and methanogenesis (42.1 %). The abundances of Euryarchaeota, Bacteroidota, and Chloroflexi at the phylum level, and Pseudomonas, and Bacillus at the genus level could highly contribute to the dechlorination mechanism and acetate transformation into CH4. This biomass-to-bioenergy project (10 m3/d capacity) could benefit from pollution reduction, biogas recovery, and carbon credit, giving 5.6 yr payback-period, 3503 USD net present value, and 12.1 % internal rate of return. Because R5 exhibited an efficient techno-economic anaerobic biodegradation performance, future studies are required to optimize its HRT condition and HAP@BC dosage.

Enhanced degradation performance toward para-nitrophenol of adapted immobilized microbial community on coconut coir

Nitrophenol pollutants, including para-nitrophenol (p-NP), are known for their harmful environmental impact due to their persistence, toxicity, and widespread distribution in water sources. While biodegradation generally offers a more effective removal of organic pollutants compared to chemical or physical methods, degrading persistent and toxic compounds like p-NP remains challenging. In this study, a microbial community derived from food processing wastewater was immobilized on coconut coir and adapted to p-NP before being employed for p-NP biodegradation. The spectroscopic analysis demonstrates the effective biodegradation performance of the adapted microbial community, achieving 99% degradation of 50 mg L⁻1 p-NP in 38 min and 250 mg L⁻1 p-NP in 4.65 h. The degradation ability of immobilized cells was determined across a broad range of stirring speeds, temperatures, pH levels, and p-NP solution volumes. Complete mineralization of p-NP was confirmed by chemical oxygen demand (COD) measurements of the treated solution and in-situ CO2 generation. Notably, the p-NP degradation performance of the adapted immobilized microbial community remained stable for the first 40 days, with only a slight decrease observed after 47 days of cold preservation at 4 °C. An average p-NP degradation rate of 0.75 mg L⁻1 min⁻1 was maintained over 54 consecutive runs. Significant alterations in microbial diversity were identified through 16S metabarcoding analysis. The unadapted microbial community comprised a diverse range of genera, while the adapted community showed reduced diversity with an enrichment of specific genera known for p-NP degradation, such as unidentified members of the Micrococcaceae family, Paenarthrobacter spp., and Zoogloea spp.

Degradable polyvinyl alcohol/chitosan@carnauba wax superhydrophobic composite membrane for water-in-oil emulsion separation and heavy metal adsorption

At present, many oil-water separation membranes are being developed to purify oily wastewater. However, oily wastewater often contains heavy metal, which are often difficult to dispose during separation. Furthermore, most of the oil-water separation membranes cannot be degraded after scrap, producing pollution to environment. Herein, the polyvinyl alcohol/chitosan@carnauba wax (PCGCW) membrane with heavy metal adsorption and biodegradation performance was acquired by electrospinning and spraying process. The acquired PCGCW membrane had excellent mechanical properties after crosslinking glutaraldehyde (GA). Furthermore, the composite membrane had excellent superhydrophobic property (WCA = 154°) with a rolling angle of 2°, due to the introduction of carnauba wax. Exhilaratingly, for emulsions with surfactant, it had a high separation flux with 19,217 L·m−2·h−1·bar−1 and splendid an oil purity over 99.9 %. Besides, the efficiency of oil purity and separation flux remained stable even after 10 separations. In addition, the PCGCW membrane had the ability to adsorb heavy metals with adsorption capacity of 51–106 mg/g for Cu2+, Fe3+, Co2+ ions. Foremost, the superhydrophobic PCGCW membrane was biodegradable, with degrading 29.76 % within 40 days. The prepared composite membrane had the advantages of low cost, high separation flux, great repeatability, adsorbable heavy metals and degradability, which had a vast application prospect.

Determination of biodegradation performance for fabricated by MEW Chitosan/PCL composite stents with in vitro tests

Today, biodegradable implants have begun to become a serious alternative to permanent implant groups. Especially the development of polymer material technology can be an alternative to metallic medical instruments. An innovative manufacturing method for the fabricated of these polymeric implants is melt electrowriting (MEW). This innovative method, which emerged as a result of studies on the production quality of additive manufacturing technology, is used in products with smaller and more complex geometries, such as stents. It is anticipated that this method, which is particularly convenient for patient-specific implant models, will have an important place in the implant production market in the future. Within the framework of this perspective, in this study, a study was conducted on the polycarbolactone group using the MEW method. In order to improve the biodegradability character, biodegradability experiments of chitosan-doped stents were conducted in vitro. The degradation character of the samples subjected to immersion corrosion in two different media for 1, 7, 14 and 21 days was examined based on residual mass. It has been determined that chitosan reinforcement has a buffering effect and plays a retarding role on the degradation time.

Use of pseudomonas fluorecens isolated from the Serra de Ouro Branco State Park/Minas Gerais - Brazil in the biodegradation of residual automotive lubricating oils

About 2% of the oil consumed worldwide is related to the production of automotive and industrial lubricating oils. The pollution derived from these oils in aquatic and terrestrial environments is responsible for several ecological and social problems due to their toxic, mutagenic, and carcinogenic properties. Thus, studies related to bioremediation are of importance, and the use of biological treatments, such as biodegradation, is a viable and effective alternative for the treatment of these compounds. The present study aimed to evaluate the biodegradation performance of residual automotive lubricating oils using the lipases Pseudomonas fluorecens obtained in bioprospecting carried out in the Serra do Ouro Branco State Park, Minas Gerais. Through the colorimetric method using the redox indicator 2.6-dichlorophenol-indophenol (DCPIP), the biodegradability of residual oils was monitored. The results obtained demonstrated the potential of the selected bacteria, since they degraded approximately 61.74 to 83.8 % of the waste studied.

Biochar modification accelerates soil atrazine biodegradation by altering bacterial communities, degradation-related genes and metabolic pathways

Atrazine is one of the most used herbicides, posing non-neglectable threats to ecosystem and human health. This work studied the performance and mechanisms of surface-modified biochar in accelerating atrazine biodegradation by exploring the changes in atrazine metabolites, bacterial communities and atrazine degradation-related genes. Among different types of biochar, nano-hydroxyapatite modified biochar achieved the highest degradation efficiency (85.13 %), mainly attributing to the increasing pH, soil organic matter, soil humus, and some enriched indigenous bacterial families of Bradyrhizobiaceae, Rhodospirillaceae, Methylophilaceae, Micrococcaceae, and Xanthobacteraceae. The abundance of 4 key atrazine degradation-related genes (atzA, atzB, atzC and triA) increased after biochar amendment, boosting both dechlorination and dealkylation pathways in atrazine metabolism. Our findings evidenced that biochar amendment could accelerate atrazine biodegradation by altering soil physicochemical properties, microbial composition and atrazine degradation pathways, providing clues for improving atrazine biodegradation performance at contaminated sites.

Biobased Polybutyrolactam Nanofiber with Excellent Biodegradability and Cell Growth for Sustainable Healthcare Textiles.

The white pollution caused by unsustainable materials is a significant challenge around the globe. Here, a novel and fully biobased polybutyrolactam (PBY) nanofiber membrane was fabricated via the electrospinning method. As-spun PBY nanofiber membranes have good thermal stability, high porosity of up to 71.94%, and excellent wetting behavior. The biodegradability in soil, UV aging irradiation, and seawater was investigated. The PBY nanofiber membrane is almost completely degraded in the soil within 80 days, showing excellent degradability. More interestingly, γ-aminobutyric acid, as a healthcare agent with intrinsic hypotensive, tranquilizing, diuretic, and antidiabetic efficacy, can be detected in the degradation intermediates. In addition, the PBY nanofiber membrane also exhibits antibacterial ability against Escherichia coli. As a fully biomass-derived material, the PBY membrane has excellent biodegradable performance in various environments as well as negligible cytotoxicity and commendable cell proliferation. Our PBY nanofiber membrane shows great potential as biodegradable packaging and in vitro healthcare materials.

Resting for viability: Gordonia polyisoprenivorans ZM27, a robust generalist for petroleum bioremediation under hypersaline stress

The intrinsic issue associated with the application of microbes for practical pollution remediation involves maintaining the expected activity of engaged strains or consortiums as effectively as that noted under laboratory conditions. Faced with various stress factors, degraders with dormancy ability are more likely to survive and exhibit degradation activity. In this study, a hydrocarbonoclastic and halotolerant strain, Gordonia polyisoprenivorans ZM27, was isolated via stimulation with resuscitation-promoting factor (Rpf). Long-term exposure to dual stresses of 10% NaCl and starvation induced ZM27 to enter a viable but nonculturable (VBNC)-like state, and ZM27 cells could be resuscitated upon Rpf stimulation. Notable changes in both morphological and physiological characteristics between VBNC-like ZM27 cells and resuscitated cells confirmed the response to Rpf and their robust resistance against harsh environments. Whole-genome sequencing and analysis indicated ZM27 could be a generalist degrader with dormancy ability. Subsequently, VBNC-like ZM27 was applied in a soil microcosm experiment to investigate the practical application potential under harsh conditions. VBNC-like ZM27 combined with Rpf stimulation exhibited the most effective biodegradation performance, and the initial n-hexadecane content (1000 mg kg−1) decreased by 63.29% after 14-day incubation. Based on 16S rRNA amplicon sequencing and analysis, Gordonia exhibited a positive response to Rpf stimulation. The relative abundance of genus Gordonia was negatively correlated with that of Alcanivorax, a genus of obligate hydrocarbon degrader with the greatest abundance during soil incubation. Based on the degradation profile and community analysis, generalist Gordonia may be more efficient in hydrocarbon degradation than specialist Alcanivorax under harsh conditions. The characteristics of ZM27, including its sustainable culturability under long-term stress, response to Rpf and robust performance in soil microcosms, are valuable for the remediation of petroleum pollution under stressful conditions. Our work validated the importance of dormancy and highlighted the underestimated role of low-activity degraders in petroleum remediation.

Syzgium cumini seed/poly vinyl alcohol based water resistant biodegradable nano-cellulose composite reinforced with zinc oxide and silver oxide nanoparticles for improved mechanical properties

The current work explored a comparative study of biodegradable jamun seed/polyvinyl alcohol (JS) nanocomposites reinforced with varying concentrations of ZnO and Ag2O nano-fillers. The effect of spherical shaped ZnO and Ag2O nanoparticles (NPs) on the on structure, morphology, swelling and solubility, crystallinity and mechanical properties together with biodegradation performance of the composite films was fully studied. SEM results showed uniform distribution of ZnO and Ag2O nanofillers into the JS matrix and dense or compact nanocomposite films were formed. JS-ZnO and JS-Ag2O nanocomposites with 0.5 wt% ZnO and Ag2O content showed maximum crystallinity i.e. 11.3 and 9.58 %, respectively, as determined by XRD. When compared to the virgin JS film (8.41 MPa), the resultant JS-ZnO-0.5 and JS-Ag2O-0.5 nanocomposites showed significantly enhanced tensile strength (35.7 MPa, 29.2 MPa), elongation at break (15.42 %, 14.62 %) and Young's modulus (141 MPa, 126 MPa), respectively. Also, reduced swelling (120.4 % and 116.1 %) and solubility ratio (17.45 % and 18.42 %) was observed for JS-ZnO-0.5 and JS-Ag2O-0.5 nanocomposites, respectively. Biodegradation results showed that maximum degradation (88 %) was achieved for the JS film within 180 days of soil burial whereas JS-ZnO-0.1 and JS-Ag2O-0.1 nanocomposites showed 78 % and 72 % degradation within 180 days, respectively.

Mechanical and degradation properties of degradable cover materials for sugarcane leaves

Mulch was prepared using composted sugarcane leaves, with polyvinyl alcohol and cationic starch as adhesives, through compression molding. The study aimed to investigate the effects of different adhesives on the mechanical properties, thermal oxidative degradation performance, and biodegradability of the covering materials. The results indicated that, when the adhesive dosage was consistent, cover material A, which utilized polyvinyl alcohol as the adhesive, exhibited higher tensile strength and elongation at break compared to cover material B, which employed a blend of polyvinyl alcohol and cationic starch. Specifically, at an adhesive dosage of 20%, cover material A achieved a tensile strength of 0.46 MPa and an elongation at break of 7.72%, representing the highest values among all experimental groups. There was minimal disparity in the thermal oxidative degradation performance between materials prepared with either adhesive; however, a higher quantity of adhesive led to decreased biodegradability performance. After being buried in soil for 120 days, the degradation exceeded 40% for both materials, resulting in loss of their original shape and strength properties. In conclusion, while sugarcane leaves-based biodegradable materials demonstrate favorable degradation performance, further enhancements are necessary to improve their mechanical properties. These materials have potential applications as substitutes for plastic mulch.

Hydro-Thermal Degradation: A New and Rapid Method for Evaluating the Bio-degradation Performance of Poly(lactic acid)

Hydro-Thermal Degradation: A New and Rapid Method for Evaluating the Bio-degradation Performance of Poly(lactic acid)

Biobased Triesters as Plasticizers for Improved Mechanical and Biodegradable Performance of Polylactic Acid Fibrous Membranes as Facemask Materials

Biobased Triesters as Plasticizers for Improved Mechanical and Biodegradable Performance of Polylactic Acid Fibrous Membranes as Facemask Materials

Effect of enhanced quenching on properties of melt spun multifilament poly[3-hydroxybutyrate] yarns

Bacterial poly-3-hydroxybutyrate is a thermoplastic biopolyester that is considered a potential alternative to traditional fossil-based plastics due to its rapid biodegradation performance in both soil and marine environments and its compostability. Due to problems in thermal and crystallization behaviors of the bacterial poly-3-hydroxybutyrate polymer, an improvement has been made in the cooling channel of the conventional fiber spinning process. Using an enhanced quench channel, named as a half tube on a conventional melt spinning line, melt spinning of the bacterial poly-3-hydroxybutyrate multifilament fibers is successfully carried out. The maximum crystallization temperature of polymers was taken into account while adjusting the quenching process. The study examined the impact of varying drawing ratios and the designed quenching apparatus on the thermal (differential scanning calorimetry), mechanical (tensile and drawing force tests), morphological, and crystal structure characteristics of fibers. The quenching apparatus has visibly created a homogeneous melt flow under the spinnerets. While it has a negative impact on fiber cross-sectional formation, raising the draw ratio greatly enhances mechanical properties.

Biogas Production Optimization in the Anaerobic Codigestion Process: A Critical Review on Process Parameters Modeling and Simulation Tools

Many operational parameters, either discretely or collectively, can influence the biodegradation performance towards enhancing biogas yield and quality. Among the operating parameters, organic loading rate (OLR), inoculum-substrate ratio, and carbon-nitrogen ratio (C/N) are the most critical parameters in the optimization and enhancement of biogas yield. Optimization of the biogas production processes depends on the ability of anaerobic microorganisms to respond to variations in operational parameters such as pH, redox potential, and intermediate products to enhance the biogas yield. This review article focuses on the role of process parameters, kinetic models, artificial intelligence, Aspen Plus (AP), and anaerobic digestion model no. 1 (ADM1) in optimizing biogas yield via an anaerobic codigestion (AcoD) process. The review showed that biomaterials codigestion upgraded biogas yield to the extent of 400%, and organic removal efficiency reached up to 90% compared to a single substrate. In addition, the current work has verified that the kinetic model is the most effective tool for signifying that the hydrolysis phase is the rate-limiting step, whereas AP is the most effective tool in the design and optimization of the AcoD process parameters. The reviewed kinetic and AI models show strong correlation values ranging from 0.931 to 0.9991 and 0.8700 to 0.9998, respectively. The AcoD system involves complex chemical reactions, but AP might have limitations in representing such complex chemical processes with nonideal behavior and complicated reaction mechanisms. The design and optimization of AcoD with reliable input parameters are highly limited or nonexistent. The AcoD process design with AP opens fresh research opportunities, including improved efficiency, finding appropriate retention time, and saving time, as well as finding the optimum biogas yield. This review article gives an insightful understanding of AcoD process parameter optimization and valuable strategies for policy development enhancing sustainability in the biogas sector.

Crude Oil Biodegradation Performance in Natural Seawater of a Trichoderma species from Decaying Mangrove Wood in East Kalimantan

Large-scale petroleum production poses environmental and human health risks, particularly due to petroleum contamination in marine environments. The aim of this study was to isolate and screen fungi inhabiting decaying mangrove wood in East Kalimantan with their ability to degrade crude oil in seawater. In the initial step, fungi were isolated using standard methods and screened for crude oil degradation and biomass production. Selected fungi were based on their significant biomass production. Subsequently, the selected fungus was cultured in three types of media based on natural seawater and crude oil at initial concentrations ranging from 1% to 5% (v/v). The biodegradation of crude oil was assessed spectrophotometrically at 420 nm. Out of the 17 decaying wood fungi, MG-07 exhibited significantly higher biomass production compared to the control medium (without crude oil). Gas chromatography-mass spectrometry analysis indicated that MG-07 degraded 20%–80% of the normal aliphatic compounds in the tested crude oils within 2 weeks. Furthermore, the growth and degradation efficiency of MG-07 was significantly enhanced when cultured in a natural seawater medium containing crude oil, supplemented with glucose (20 g/L) and Tween 80 (1% v/v). The highest observed biomass gains were 867%, with a biodegradation efficiency of 31.6% at a crude oil concentration of 1%. MG-07 was identified as Trichoderma sp. based on the internal transcribed spacer region. The results obtained from this study demonstrate that MG-07 has significant potential for degrading crude oil in saline environments. These findings provide valuable insights for the application of fungi in marine oil spill remediation.

Closed-Loop Polymer-to-Polymer Upcycling of Waste Poly (Ethylene Terephthalate) into Biodegradable and Programmable Materials.

Poly(ethylene terephthalate) (PET), extensively employed in bottles, film, and fiber manufacture, has generated persistent environmental contamination due to its non-degradable nature. The resolution of this issue requires the conversion of waste PET into valuable products, often achieved through depolymerization into monomers. However, the laborious purification procedures involved in the extraction of monomers pose challenges and constraints on the complete utilization of PET. Herein, a strategy is demonstrated for the polymer-to-polymer upcycling of waste PET into high-value biodegradable and programmable materials named PEXT. This process involves reversible transesterifications dependent on ester bonds, wherein commercially available X-monomers from aliphatic diacids and diols are introduced, utilizing existing industrial equipment for complete PET utilization. PEXT features a programmable molecular structure, delivering tailored mechanical, thermal, and biodegradation performance. Notably, PEXT exhibits superior mechanical performance, with a maximal elongation at break of 3419.2 % and a toughness of 270.79 MJ m-3. These characteristics make PEXT suitable for numerous applications, including shape-memory materials, transparent films, and fracture-resistant stretchable components. Significantly, PEXT allows closed-loop recycling within specific biodegradable analogs by reprograming PET or X-monomers. This strategy not only offers cost-effective advantages in large-scale upcycling of waste PET into advanced materials but also demonstrates its enormous prospect in environmental conservation.

Biodegradation performance of ball burnished magnesium alloy in stimulated body fluids for bioresorbable implant applications

Magnesium alloys are found to be potential bioresorbable materials. However, the application range of these alloys as bioresorbable materials has been limited due to rapid degradation in physiological fluids. The current study deals with the enhancement of degradation behavior of Mg Ze41A alloy in SBF solution by ball burnishing. Further, the influence of burnishing parameters on biodegradation rate has been investigated by Tafel plots, polarization resistance, electrochemical impedance spectroscopy and surface morphology analysis of degraded samples. Additionally, the biodegradation rate has been estimated by ANFIS modeling. The biodegradation rate of Mg Ze41A has been reduced from 1.106 mm/yr to 0.367 mm/yr with an improvement of 68.82% at optimum burnishing condition of burnishing force 50 N, burnishing speed 1400 RPM, burnishing feed 125 mm/min and 2 passes. ANOVA analysis has revealed that burnishing force and feed have contributed the most for the enhancement. The shift in degradation potential towards noble direction and reduction in degradation current density in potentiodynamic polarization curves and the highest charge transfer resistance in electrochemical impedance spectroscopy of the burnished samples are observed for burnished samples. The results reveal that ball burnishing process is a potential surface modification method in reducing the biodegradation rate of Mg Ze41A alloy. The ball burnishing has resulted in lowest biodegradation rate at a degradation current density of 5.743 μA/cm2 and degradation potential of −1.513 V. The ANFIS model developed with 81 fuzzy rules and triangular membership function estimated the biodegradation rate with an accuracy of 95.03%. The decrease in biodegradation rate of ball burnished magnesium substrate in SBF is essentially due to cumulative effect of compressive residual stress, microhardness, surface finish, work hardening and grain refinement.

Degradation of Chloroquine by Ammonia-Oxidizing Bacteria: Performance, Mechanisms, and Associated Impact on N2O Production.

Since the mass production and extensive use of chloroquine (CLQ) would lead to its inevitable discharge, wastewater treatment plants (WWTPs) might play a key role in the management of CLQ. Despite the reported functional versatility of ammonia-oxidizing bacteria (AOB) that mediate the first step for biological nitrogen removal at WWTP (i.e., partial nitrification), their potential capability to degrade CLQ remains to be discovered. Therefore, with the enriched partial nitrification sludge, a series of dedicated batch tests were performed in this study to verify the performance and mechanisms of CLQ biodegradation under the ammonium conditions of mainstream wastewater. The results showed that AOB could degrade CLQ in the presence of ammonium oxidation activity, but the capability was limited by the amount of partial nitrification sludge (∼1.1 mg/L at a mixed liquor volatile suspended solids concentration of 200 mg/L). CLQ and its biodegradation products were found to have no significant effect on the ammonium oxidation activity of AOB while the latter would promote N2O production through the AOB denitrification pathway, especially at relatively low DO levels (≤0.5 mg-O2/L). This study provided valuable insights into a more comprehensive assessment of the fate of CLQ in the context of wastewater treatment.