Maturation Kinetics of a Multiprotein Complex Revealed by Metabolic Labeling.

All proteins interact with other cellular components to fulfill their function. While tremendous progress has been made in the identification of protein complexes, their assembly and dynamics remain difficult to characterize. Here, we present a high-throughput strategy to analyze the native assembly kinetics of protein complexes. We apply our approach to characterize the co-assembly for 320 pairs of nucleoporins (NUPs) constituting the ≈50 MDa nuclear pore complex (NPC) in yeast. Some NUPs co-assemble fast via rapid exchange whereas others require lengthy maturation steps. This reveals a hierarchical principle of NPC biogenesis where individual subcomplexes form on a minute timescale and then co-assemble from center to periphery in a ∼1 h-long maturation process. Intriguingly, the NUP Mlp1 stands out as joining very late and associating preferentially with aged NPCs. Our approach is readily applicable beyond the NPC, making it possible to analyze the intracellular dynamics of a variety of multiprotein assemblies.

Engineering Escherichia coli for efficient glutathione production.

Glutathione is a tripeptide of excellent value in the pharmaceutical, food, and cosmetic industries that is currently produced during yeast fermentation. In this case, glutathione accumulates intracellularly, which hinders high production. Here, we engineered Escherichia coli for the efficient production of glutathione. A total of 4.3 g/L glutathione was produced by overexpressing gshA and gshB, which encode cysteine glutamate ligase and glutathione synthetase, respectively, and most of the glutathione was excreted into the culture medium. Further improvements were achieved by inhibiting degradation (Δggt and ΔpepT); deleting gor (Δgor), which encodes glutathione oxide reductase; attenuating glutathione uptake (ΔyliABCD); and enhancing cysteine production (PompF-cysE). The engineered strain KG06 produced 19.6 g/L glutathione after 48 h of fed-batch fermentation with continuous addition of ammonium sulfate as the sulfur source. We also found that continuous feeding of glycine had a crucial role for effective glutathione production. The results of metabolic flux and metabolomic analyses suggested that the conversion of O-acetylserine to cysteine is the rate-limiting step in glutathione production by KG06. The use of sodium thiosulfate largely overcame this limitation, increasing the glutathione titer to 22.0 g/L, which is, to our knowledge, the highest titer reported to date in the literature. This study is the first report of glutathione fermentation without adding cysteine in E. coli. Our findings provide a great potential of E. coli fermentation process for the industrial production of glutathione.

Mass-Balance-Consistent Geological Stock Accounting: A New Approach toward Sustainable Management of Mineral Resources.

Global resource extraction raises concerns about environmental pressures and the security of mineral supply. Strategies to address these concerns depend on robust information on natural resource endowments, and on suitable methods to monitor and model their changes over time. However, current mineral resources and reserves reporting and accounting workflows are poorly suited for addressing mineral depletion or answering questions about the long-term sustainable supply. Our integrative review finds that the lack of a robust theoretical concept and framework for mass-balance (MB)-consistent geological stock accounting hinders systematic industry-government data integration, resource governance, and strategy development. We evaluate the existing literature on geological stock accounting, identify shortcomings of current monitoring of mine production, and outline a conceptual framework for MB-consistent system integration based on material flow analysis (MFA). Our synthesis shows that recent developments in Earth observation, geoinformation management, and sustainability reporting act as catalysts that make MB-consistent geological stock accounting increasingly feasible. We propose first steps for its implementation and anticipate that our perspective as "resource realists" will facilitate the integration of geological and anthropogenic material systems, help secure future mineral supply, and support the global sustainability transition.

Variational Bayesian Approximation (VBA): Implementation and Comparison of Different Optimization Algorithms.

In any Bayesian computations, the first step is to derive the joint distribution of all the unknown variables given the observed data. Then, we have to do the computations. There are four general methods for performing computations: Joint MAP optimization; Posterior expectation computations that require integration methods; Sampling-based methods, such as MCMC, slice sampling, nested sampling, etc., for generating samples and numerically computing expectations; and finally, Variational Bayesian Approximation (VBA). In this last method, which is the focus of this paper, the objective is to search for an approximation for the joint posterior with a simpler one that allows for analytical computations. The main tool in VBA is to use the Kullback-Leibler Divergence (KLD) as a criterion to obtain that approximation. Even if, theoretically, this can be conducted formally, for practical reasons, we consider the case where the joint distribution is in the exponential family, and so is its approximation. In this case, the KLD becomes a function of the usual parameters or the natural parameters of the exponential family, where the problem becomes parametric optimization. Thus, we compare four optimization algorithms: general alternate functional optimization; parametric gradient-based with the normal and natural parameters; and the natural gradient algorithm. We then study their relative performances on three examples to demonstrate the implementation of each algorithm and their efficiency performance.

The inhibitor of MyoD Family A (I-MFA) regulates megakaryocyte lineage commitment and terminal differentiation.

Hematopoiesis and lineage commitment are regulated by several conserved cell-intrinsic signaling pathways, including MAPKs and ß-catenin/TCF/LEF. The Inhibitor of MyoD Family A (I-MFA), a transcriptional repressor and tumor suppressor gene, interacts with these pathways and is dysregulated in chronic and acute myeloid leukemias, suggesting it may play a role in development and differentiation during hematopoiesis. To study this, immune cell populations in the bone marrow (BM) and periphery were analyzed in mice lacking Mdfi, encoding I-MFA (I-MFA-/-), and wild type (WT) controls. I-MFA-/- mice had reduced spleen and BM cellularity, with significant hyposplenism, compared to WT mice. In blood, total red blood cells and platelet counts were significantly reduced in I-MFA-/- mice, accompanied by a reduction in megakaryocyte (MK)/erythrocyte progenitor cells and an increase in myeloid progenitors in BM compared to WT mice. The K562 cell line exhibits PMA-induced MK differentiation, and shRNA knockdown of I-MFA resulted in reduced differentiation compared to control, with an increase and prolongation in phospho-JNK and phospho-ERK signaling. Overexpression of I-MFA promoted MK differentiation. These results suggest I-MFA plays a cell-intrinsic role in the response to differentiation signals, an effect that can be explored in the context of hematological cancers or other blood proliferative disorders.

Silk fibroin production in Escherichia coli is limited by a positive feedback loop between metabolic burden and toxicity stress.

To investigate the metabolic elasticity and production bottlenecks for recombinant silk proteins in Escherichia coli, we performed a comprehensive characterization of one elastin-like peptide strain (ELP) and two silk protein strains (A5 4mer, A5 16mer). Our approach included 13C metabolic flux analysis, genome-scale modeling, transcription analysis, and 13C-assisted media optimization experiments. Three engineered strains maintained their central flux network during growth, while measurable metabolic flux redistributions (such as the Entner-Doudoroff pathway) were detected. Under metabolic burdens, the reduced TCA fluxes forced the engineered strain to rely more on substrate-level phosphorylation for ATP production, which increased acetate overflow. Acetate (as low as 10 mM) in the media was highly toxic to silk-producing strains, which reduced 4mer production by 43% and 16mer by 84%, respectively. Due to the high toxicity of large-size silk proteins, 16mer's productivity was limited, particularly in the minimal medium. Therefore, metabolic burden, overflow acetate, and toxicity of silk proteins may form a vicious positive feedback loop that fractures the metabolic network. Three solutions could be applied: 1) addition of building block supplements (i.e., eight key amino acids: His, Ile, Phe, Pro, Tyr, Lys, Met, Glu) to reduce metabolic burden; 2) disengagement of growth and production; and 3) use of non-glucose based substrate to reduce acetate overflow. Other reported strategies were also discussed in light of decoupling this positive feedback loop.

BAuth-ZKP-A Blockchain-Based Multi-Factor Authentication Mechanism for Securing Smart Cities.

The overwhelming popularity of technology-based solutions and innovations to address day-to-day processes has significantly contributed to the emergence of smart cities. where millions of interconnected devices and sensors generate and share huge volumes of data. The easy and high availability of rich personal and public data generated in these digitalized and automated ecosystems renders smart cities vulnerable to intrinsic and extrinsic security breaches. Today, with fast-developing technologies, the classical username and password approaches are no longer adequate to secure valuable data and information from cyberattacks. Multi-factor authentication (MFA) can provide an effective solution to minimize the security challenges associated with legacy single-factor authentication systems (both online and offline). This paper identifies and discusses the role and need of MFA for securing the smart city ecosystem. The paper begins by describing the notion of smart cities and the associated security threats and privacy issues. The paper further provides a detailed description of how MFA can be used for securing various smart city entities and services. A new concept of blockchain-based multi-factor authentication named "BAuth-ZKP" for securing smart city transactions is presented in the paper. The concept focuses on developing smart contracts between the participating entities within the smart city and performing the transactions with zero knowledge proof (ZKP)-based authentication in a secure and privacy-preserved manner. Finally, the future prospects, developments, and scope of using MFA in smart city ecosystem are discussed.

Decoupling analysis between economic growth and aluminum cycle: From the perspective of aluminum use and carbon emissions.

Increasing aluminum demand under the clean energy and low-carbon transformation background increases the fuzziness of relationships between economic growth and aluminum use or aluminum related carbon emissions. To figure this out, this paper established an aluminum use and carbon emissions integrated decoupling model within the framework of anthropogenic aluminum cycle. A material flow analysis (MFA) during 2000-2020 for China's aluminum cycle was firstly conducted to quantify both aluminum flow and carbon emissions in each aluminum life-cycle process. Then, this paper evaluated and decomposed the decoupling index of aluminum use-economy and carbon emission-economy via the LMDI decomposition model. Results show that: (1) secondary aluminum has not become effective supplement for primary aluminum in China; (2) the expansive negative decoupling state was the most prevalent state. The decoupling effects of carbon emission were better than that of aluminum use; (3) technology improvement was an important impactor to decoupling process but didn't offset the growth in aluminum consumption or carbon emissions at most of the time. The government and industry organizers should implement active countermeasures to stimulate aluminum companies developing technology to improve aluminum use efficiency and reduce carbon emissions.

Sustainable development of urban agglomeration based on material metabolism: a case study on Fujian Delta, China.

As highly concentrated urbanized areas, urban agglomerations bear increasing resource depletion and environmental pressures, which threaten the regional sustainable development. Resource and environmental problems arising from the process of urbanization can be attributed to the dislocation or maladjustment of material metabolism in time or space. Conducting research on material metabolism at the level of urban agglomerations is helpful in finding the root causes of environmental problems to provide support for the reduction of regional resource consumption and pollution emissions. The material metabolism characteristics of the urban agglomeration and internal cities of the Fujian Delta Urban Agglomeration (FDUA) in China are evaluated using the material flow analysis. The following results are observed. (1) The economic development of the FDUA is still at risk of resource consumption, and a large proportion of hidden flow (HF > 80%) drags down the overall metabolic efficiency and sustainable development. (2) The discharge of various pollutants in the FDUA generally shows a downward trend. Improving metabolic efficiency, delayed MCI growth, and improved overall regional environmental quality are observed. (3) Cities that have relatively scarce land resources but are economically developed, such as Xiamen, still bear a relatively heavy ecological burden (ECdmc > 1). (4) Regional collaboration is conducive to the sustainable development of multiple regions. On the one hand, the results of this study provide decision-making basis for the sustainable development of the national ecological civilization demonstration area. On the other hand, this work guides the establishment of a comprehensive industrial linkage and cooperation mechanism for the same type of small- and medium-sized urban agglomerations.

Porphyromonas gingivalis Mfa1 fimbria putatively binds to TLR2 and induces both IL-6 and IL-8 production in human bronchial epithelial cells.

Porphyromonas gingivalis (Pg) a major periodontal pathogen involved in periodontal disease development and progression. Moreover, Pg has two fimbriae surface proteins (FimA and Mfa1) that are genetically distinct and make-up the fimbrial shaft which in-turn form crucial attachment to oral bacteria and multiple host cells. However, unlike FimA, Mfa1 attachment to non-periodontal cells has not been fully elucidated. Considering Pg-associated periodontal disease contributes to pulmonary disease development, we investigated whether Mfa1 can functionally interact with human bronchial epithelial cells and, likewise, trigger a functional response. Initially, we simulated molecular docking and performed both luciferase and neutralization assays to confirm Mfa1-related functional interaction. Subsequently, we treated BEAS-2B cells with purified Mfa1 and performed cytokine quantification through real time-PCR and ELISA to establish Mfa1-related functional response. We found that both Mfa1-TLR2 and Mfa1-TLR4 docking is possible, however, only Mfa1-TLR2 showed a functional interaction. Additionally, we observed that both IL-8 and IL-6 gene expression and protein levels were induced confirming Mfa1-related functional response. Taken together, we propose that BEAS-2B human bronchial epithelial cells are able to recognize Pg Mfa1 and induce both IL-8 and IL-6 inflammatory responses.

Radial microfibril arrangements in wood cell walls.

MAIN CONCLUSION: TEM and AFM imaging reveal radial orientations and whorl-like arrangements of cellulose microfibrils near the S1/S2 interface. These are explained by wrinkling during lamellar cell growth. In the most widely accepted model of the ultrastructure of wood cell walls, the cellulose microfibrils are arranged in helical patterns on concentric layers. However, this model is contradicted by a number of transmission electron microscopy (TEM) studies which reveal a radial component to the microfibril orientations in the cell wall. The idea of a radial component of the microfibril directions is not widely accepted, since it cannot easily be explained within the current understanding of lamellar cell growth. To help clarify the microfibril arrangements in wood cell walls, we have investigated various wood cell wall sections using both transmission electron microscopy and atomic force microscopy, and using various imaging and specimen preparation methods. Our investigations confirm that the microfibrils have a radial component near the interface between the S1 and S2 cell wall layers, and also reveal a whorl-like microfibril arrangement at the S1/S2 interface. These whorl-like structures are consistent with cell wall wrinkling during growth, allowing the radial microfibril component to be reconciled with the established models for lamellar cell growth.

INCA 2.0: A tool for integrated, dynamic modeling of NMR- and MS-based isotopomer measurements and rigorous metabolic flux analysis.

Metabolic flux analysis (MFA) combines experimental measurements and computational modeling to determine biochemical reaction rates in live biological systems. Advancements in analytical instrumentation, such as nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS), have facilitated chemical separation and quantification of isotopically enriched metabolites. However, no software packages have been previously described that can integrate isotopomer measurements from both MS and NMR analytical platforms and have the flexibility to estimate metabolic fluxes from either isotopic steady-state or dynamic labeling experiments. By applying physiologically relevant cardiac and hepatic metabolic models to assess NMR isotopomer measurements, we herein test and validate new modeling capabilities of our enhanced flux analysis software tool, INCA 2.0. We demonstrate that INCA 2.0 can simulate and regress steady-state 13C NMR datasets from perfused hearts with an accuracy comparable to other established flux assessment tools. Furthermore, by simulating the infusion of three different 13C acetate tracers, we show that MFA based on dynamic 13C NMR measurements can more precisely resolve cardiac fluxes compared to isotopically steady-state flux analysis. Finally, we show that estimation of hepatic fluxes using combined 13C NMR and MS datasets improves the precision of estimated fluxes by up to 50%. Overall, our results illustrate how the recently added NMR data modeling capabilities of INCA 2.0 can enable entirely new experimental designs that lead to improved flux resolution and can be applied to a wide range of biological systems and measurement time courses.

Metabolic analysis of the asparagine and glutamine dynamics in an industrial Chinese hamster ovary fed-batch process.

Chinese hamster ovary (CHO) cell lines are grown in cultures with varying asparagine and glutamine concentrations, but further study is needed to characterize the interplay between these amino acids. By following 13 C-glucose, 13 C-glutamine, and 13 C-asparagine tracers using metabolic flux analysis (MFA), CHO cell metabolism was characterized in an industrially relevant fed-batch process under glutamine supplemented and low glutamine conditions during early and late exponential growth. For both conditions MFA revealed glucose as the primary carbon source to the tricarboxylic acid (TCA) cycle followed by glutamine and asparagine as secondary sources. Early exponential phase CHO cells prefer glutamine over asparagine to support the TCA cycle under the glutamine supplemented condition, while asparagine was critical for TCA activity for the low glutamine condition. Overall TCA fluxes were similar for both conditions due to the trade-offs associated with reliance on glutamine and/or asparagine. However, glutamine supplementation increased fluxes to alanine, lactate and enrichment of glutathione, N-acetyl-glucosamine and pyrimidine-containing-molecules. The late exponential phase exhibited reduced central carbon metabolism dominated by glucose, while lactate reincorporation and aspartate uptake were preferred over glutamine and asparagine. These 13 C studies demonstrate that metabolic flux is process time dependent and can be modulated by varying feed composition.

Porphyromonas gingivalis Fimbriae Induce Osteoclastogenesis via Toll-like Receptors in RAW264 Cells.

The effect of Mfa1 fimbriae of Porphyromonas gingivalis on the progression of bone resorption remains unclear, especially compared with another fimbriae, FimA. We investigated the effect of Mfa1 on osteoclastogenesis together with FimA. We also investigated the role of Toll-like receptors (TLRs) in Mfa1 recognition during osteoclast differentiation. Receptor activator of nuclear factor κß ligand (RANKL)-prestimulated RAW264 cells were used to examine the effects of purified Mfa1 fimbriae. The number of osteoclasts was examined by tartrate-resistant acid phosphate (TRAP) staining, osteoclast activation was investigated by bone resorption assays, and gene expression of differentiation markers was examined by quantitative real-time PCR. Transfection of Tlr2 and Tlr4 siRNAs into RAW264 cells was also employed and their role in Mfa1 recognition was investigated. Mfa1 effectively induced the formation of TRAP-positive multinucleated cells and activated osteoclasts. Mfa1 also increased gene expression of Acp5, Mmp9, and Ctsk in RANKL-prestimulated RAW264 cells compared with the control. The osteoclastogenesis induced by Mfa1 was significantly decreased in cells transfected with Tlr2 or Tlr4 siRNAs compared with control siRNA. Our results revealed the role of Mfa1 fimbriae in osteoclastogenesis that may contribute to the partial elucidation of the mechanisms of periodontal disease progression and the development of new therapeutic strategies.

On the implementation of the circular economy route for E-waste management: A critical review and an analysis for the case of the state of Kuwait.

Electronic waste (e-waste) has become one of the major causes of environmental concerns due to its large volume, high generation rate and toxic environmental burdens. Recent estimates put e-waste generation at about 54 million tonnes per annum with figures reaching approximately 75 million tonnes per annum by 2030. In this manuscript, the state-of-the-art technologies and techniques for segregation, recovery and recycling of e-waste with a special focus on the valorisation aspects of e-plastics and e-metals which are critically reviewed. A history and insight into environmental aspects and regulation/legislations are presented including those that could be adopted in the near future for e-waste management. The prospects of implementing such technologies in the State of Kuwait for the recovery of materials and energy from e-waste where infrastructure is lacking still for waste management are presented through Material Flow Analysis. The information showed that Kuwait has a major problem in waste accumulation. It is estimated that e-waste in Kuwait (with no accumulation or backlog) is generated at a rate of 67,000 tpa, and the imports of broadcasting electronics generate some 19,428 tonnes. After reviewing economic factors of potential recovered plastics, iron and glass from broadcasting devices in Kuwait as e-waste, a total revenue of $399,729 per annum is estimated from their valorisation. This revenue will open the prospect of ventures for other e-waste and fuel recovery options as well as environmental benefits and the move to a circular economy.

Investigation of the nitrogen flows of the food supply chain in Beijing-Tianjin-Hebei region, China during 1978-2017.

Reactive nitrogen (Nr) is an indispensable material for food production. However, it may cause serious environmental problems. The enhancement of nitrogen management in the food supply chain is an effective way to reduce Nr loss and increase Nr use efficiency. While Nr flows in association with the food chain have synergy in a mega-region, in-depth investigations at a cross-regional scale have remained relatively undocumented. This study developed a food-related Nr flow model based on a material flow analysis for the Beijing-Tianjin-Hebei region (BTH) during the years 1978-2017. A multi-regional input-output method was applied to investigate the Nr emissions embodied in the transboundary food supply. The results showed that the total Nr emissions from the food system during the years 1978-2017 in the BTH region increased until 2004 and subsequently decreased gradually. In 2017, Beijing exhibited the lowest Nr emissions per capita (2.3 kg N/cap) and per land use (3089 kg N/km2), while Hebei and Tianjin demonstrated the greatest Nr emissions intensity by capita (13.6 kg N/cap) and by land use (6392 kg N/km2), respectively. While farming and livestock husbandry dominated the regional Nr emissions (i.e., responsible for 90% of the total in 2017), food consumption and waste management have had an increasingly substantial role, as their shared percentage in the total increased by 22% over the study period. Nr emissions resulting from the inner-transboundary food supply chain decreased by 81% between 2012 and 2015 but dramatically increased by 231% between 2015 and 2017. This rebound effect partially resulted from the implementation of coordinated development planning for the BTH region in 2015. This study can facilitate the efficient regulation of regional nitrogen flows and the desired transition of food supply chain.

A unified framework for the integration of multiple hierarchical clusterings or networks from multi-source data.

BACKGROUND: Integrating data from different sources is a recurring question in computational biology. Much effort has been devoted to the integration of data sets of the same type, typically multiple numerical data tables. However, data types are generally heterogeneous: it is a common place to gather data in the form of trees, networks or factorial maps, as these representations all have an appealing visual interpretation that helps to study grouping patterns and interactions between entities. The question we aim to answer in this paper is that of the integration of such representations. RESULTS: To this end, we provide a simple procedure to compare data with various types, in particular trees or networks, that relies essentially on two steps: the first step projects the representations into a common coordinate system; the second step then uses a multi-table integration approach to compare the projected data. We rely on efficient and well-known methodologies for each step: the projection step is achieved by retrieving a distance matrix for each representation form and then applying multidimensional scaling to provide a new set of coordinates from all the pairwise distances. The integration step is then achieved by applying a multiple factor analysis to the multiple tables of the new coordinates. This procedure provides tools to integrate and compare data available, for instance, as tree or network structures. Our approach is complementary to kernel methods, traditionally used to answer the same question. CONCLUSION: Our approach is evaluated on simulation and used to analyze two real-world data sets: first, we compare several clusterings for different cell-types obtained from a transcriptomics single-cell data set in mouse embryos; second, we use our procedure to aggregate a multi-table data set from the TCGA breast cancer database, in order to compare several protein networks inferred for different breast cancer subtypes.

Salt, glucose, glycine, and sucrose protect Escherichia coli O157:H7 against acid treatment in laboratory media.

This study investigated the effects of combinations of acetic or malic acid and various solutes (salt, glucose, glycine, or sucrose) on the survival of Escherichia coli O157:H7 in laboratory broth. Additionally, the effectiveness of combining organic acids and various concentrations of salt (0-18%) or sucrose (0-100%) with different water activity values against E. coli O157:H7 were evaluated. For treatment of 1% malic acid, the addition of 3% salt showed synergistic effect. Whereas, when 3% salt, glucose, glycine, or sucrose was added to 1% acetic acid, the solutes antagonized the action of the acid against E. coli O157:H7. Acetic, lactic, or propionic acid combined with salt at either 7 or 9% or sucrose at 60, 80, or 100% resulted in the highest resistance of E. coli O157:H7. From a result of evaluating the membrane fatty acid (MFA) composition of cells, salt or sucrose significantly increased levels of saturated fatty acids (SFAs) or SFAs and cyclopropane fatty acids, respectively. From the results of this study, the addition of solutes and organic compounds may increase the tolerance of E. coli O157:H7 to acetic, lactic, and propionic acid treatments and that the salt or sucrose significantly affects cell MFA composition.

Optimised collection of non-uniformly sampled 2D-HSQC NMR spectra for use in metabolic flux analysis.

Nuclear magnetic resonance (NMR) spectroscopy is integral to metabolic studies; yet, it can suffer from the long acquisition times required to collect data of sufficient signal strength and resolution. The use of non-uniform sampling (NUS) allows faster collection of NMR spectra without loss of spectral integrity. When planning experimental methodologies to perform metabolic flux analysis (MFA) of cell metabolism, a variety of options are available for the acquisition of NUS NMR data. Before beginning data collection, decisions have to be made regarding selection of pulse sequence, number of transients and NUS specific parameters such as the sampling level and sampling schedule. Poor choices will impact data quality, which may have a negative effect on the subsequent analysis and biological interpretation. Herein, we describe factors that should be considered when setting up non-uniformly sampled 2D-1 H,13 C HSQC NMR experiments for MFA and provide a standard protocol for users to follow.

Role and potential of the circular economy in managing end-of-life ships in china.

China's circular economy has made notable progress since the 21st century and shaped various industry segments. Among these, ship recycling has been particularly outstanding as it evolved exceptionally fast and assumed an internationally leading role. In this article, we present field survey findings on recycling standards and recovery capacities regarding the material flows at Chinese shipbreaking yards, which overall perform comparatively sustainable. However, recent policy and market developments have induced the sector's decline, which at present seems to threaten the very fundamentals of circular economic management for obsolete vessels in China. Given these limited prospects for traditional recycling approaches in the near future, the article proceeds to evaluate alternative circular economy management options for Chinese ship recycling facilities to manage end-of-life vessels. Based on quantifications of hidden potentials in ship supply, value and material contributions to the domestic circular economy, technical and market specific conditions for material recovery as well as other circular economy practices, we find that ship repair and refurbishment may offer the most promising alternative to recycling for Chinese shipbreaking yards.