Biochemistry of Catabolic Reductive Dehalogenation.

A wide range of phylogenetically diverse microorganisms couple the reductive dehalogenation of organohalides to energy conservation. Key enzymes of such anaerobic catabolic pathways are corrinoid and Fe-S cluster-containing, membrane-associated reductive dehalogenases. These enzymes catalyze the reductive elimination of a halide and constitute the terminal reductases of a short electron transfer chain. Enzymatic and physiological studies revealed the existence of quinone-dependent and quinone-independent reductive dehalogenases that are distinguishable at the amino acid sequence level, implying different modes of energy conservation in the respective microorganisms. In this review, we summarize current knowledge about catabolic reductive dehalogenases and the electron transfer chain they are part of. We review reaction mechanisms and the role of the corrinoid and Fe-S cluster cofactors and discuss physiological implications.

An uncharacteristically low-potential flavin governs the energy landscape of electron bifurcation.

Electron bifurcation, an energy-conserving process utilized extensively throughout all domains of life, represents an elegant means of generating high-energy products from substrates with less reducing potential. The coordinated coupling of exergonic and endergonic reactions has been shown to operate over an electrochemical potential of ∼1.3 V through the activity of a unique flavin cofactor in the enzyme NADH-dependent ferredoxin-NADP+ oxidoreductase I. The inferred energy landscape has features unprecedented in biochemistry and presents novel energetic challenges, the most intriguing being a large thermodynamically uphill step for the first electron transfer of the bifurcation reaction. However, ambiguities in the energy landscape at the bifurcating site deriving from overlapping flavin spectral signatures have impeded a comprehensive understanding of the specific mechanistic contributions afforded by thermodynamic and kinetic factors. Here, we elucidate an uncharacteristically low two-electron potential of the bifurcating flavin, resolving the energetic challenge of the first bifurcation event.

Perspective elucidating the physiology of a microbial cell: Neidhardt's Holy Grail.

A living microbial cell represents a system of high complexity, integration, and extreme order. All processes within that cell interconvert free energy through a multitude of interconnected metabolic reactions that help to maintain the cell in a state of low entropy, which is a characteristic of all living systems. The study of macromolecular interactions outside this cellular environment yields valuable information about the molecular function of macromolecules but represents a system in comparative disorder. Consequently, care must always be taken in interpreting the information gleaned from such studies and must be compared with how the same macromolecules function in vivo, otherwise, discrepancies can arise. The importance of combining reductionist approaches with the study of whole-cell microbial physiology is discussed regarding the long-term aim of understanding how a cell functions in its entirety. This can only be achieved by the continued development of high-resolution structural and multi-omic technologies. It is only by studying the whole cell that we can ever hope to understand how living systems function.

Metabolism of novel potential syntrophic acetate-oxidizing bacteria in thermophilic methanogenic chemostats.

Acetate is a major intermediate in the anaerobic digestion of organic waste to produce CH4. In methanogenic systems, acetate degradation is carried out by either acetoclastic methanogenesis or syntrophic degradation by acetate oxidizers and hydrogenotrophic methanogens. Due to challenges in the isolation of syntrophic acetate-oxidizing bacteria (SAOB), the diversity and metabolism of SAOB and the mechanisms of their interactions with methanogenic partners are not fully characterized. In this study, the in situ activity and metabolic characteristics of potential SAOB and their interactions with methanogens were elucidated through metagenomics and metatranscriptomics. In addition to the reported SAOB classified in the genera Tepidanaerobacter, Desulfotomaculum, and Thermodesulfovibrio, we identified a number of potential SAOB that are affiliated with Clostridia, Thermoanaerobacteraceae, Anaerolineae, and Gemmatimonadetes. The potential SAOB possessing the glycine-mediated acetate oxidation pathway dominates SAOB communities. Moreover, formate appeared to be the main product of the acetate degradation by the most active potential SAOB. We identified the methanogen partner of these potential SAOB in the acetate-fed chemostat as Methanosarcina thermophila. The dominated potential SAOB in each chemostat had similar metabolic characteristics, even though they were in different fatty-acid-fed chemostats. These novel syntrophic lineages are prevalent and may play critical roles in thermophilic methanogenic reactors. This study expands our understanding of the phylogenetic diversity and in situ biological functions of uncultured syntrophic acetate degraders and presents novel insights into how they interact with methanogens.IMPORTANCECombining reactor operation with omics provides insights into novel uncultured syntrophic acetate degraders and how they perform in thermophilic anaerobic digesters. This improves our understanding of syntrophic acetate degradation and contributes to the background knowledge necessary to better control and optimize anaerobic digestion processes.

Collaborative effect of the energy conservation and emission reduction fiscal policy in China.

Government-led national comprehensive demonstration cities for Energy Conservation and Emission Reduction Fiscal Policy (ECERFP) are pivotal for China in addressing environmental governance. Using a panel dataset covering 278 Chinese cities from 2003 to 2019, this study adopts the staggered difference-in-differences (DID) approach to investigate the synergistic impacts of ECERFP on pollution and carbon reduction. The findings indicate that ECERFP contributes to a 3% improvement in pollution reduction performance, a 1.5% enhancement in carbon reduction performance, and a 4% overall increase in combined pollution and carbon reduction efforts. Furthermore, the study examines the heterogeneous effects of ECERFP on environmental performance. ECERFP significantly influences the synergistic efforts in pollution and carbon reduction by fostering green innovation, enhancing energy allocation, and optimizing industrial structures. This study both theoretically and empirically outlines the specific pathways and mechanisms through which "incentive-based" green fiscal policy promotes synergistic pollution and carbon reduction, thus providing a pragmatic foundation for enhancing the role of fiscal policy in environmental governance.

SWARAM: Osprey Optimization Algorithm-Based Energy-Efficient Cluster Head Selection for Wireless Sensor Network-Based Internet of Things.

The Internet of Things (IoT) has transformed various aspects of human life nowadays. In the IoT transformative paradigm, sensor nodes are enabled to connect multiple physical devices and systems over the network to collect data from remote places, namely, precision agriculture, wildlife conservation, intelligent forestry, and so on. The battery life of sensor nodes is limited, affecting the network's lifetime, and requires continuous maintenance. Energy conservation has become a severe problem of IoT. Clustering is essential in IoT to optimize energy efficiency and network longevity. In recent years, many clustering protocols have been proposed to improve network lifetime by conserving energy. However, the network experiences an energy-hole issue due to picking an inappropriate Cluster Head (CH). CH node is designated to manage and coordinate communication among nodes in a particular cluster. The redundant data transmission is avoided to conserve energy by collecting and aggregating from other nodes in clusters. CH plays a pivotal role in achieving efficient energy optimization and network performance. To address this problem, we have proposed an osprey optimization algorithm based on energy-efficient cluster head selection (SWARAM) in a wireless sensor network-based Internet of Things to pick the best CH in the cluster. The proposed SWARAM approach consists of two phases, namely, cluster formation and CH selection. The nodes are clustered using Euclidean distance before the CH node is selected using the SWARAM technique. Simulation of the proposed SWARAM algorithm is carried out in the MATLAB2019a tool. The performance of the SWARAM algorithm compared with existing EECHS-ARO, HSWO, and EECHIGWO CH selection algorithms. The suggested SWARAM improves packet delivery ratio and network lifetime by 10% and 10%, respectively. Consequently, the overall performance of the network is improved.

Treatment of low-C/N nitrate wastewater using a partial denitrification-anammox granule system: Granule reconstruction, stability, and microbial structure analyses.

Industrial wastewater discharged into sewer systems is often characterized by high nitrate contents and low C/N ratios, resulting in high treatment costs when using conventional activated sludge methods. This study introduces a partial denitrification-anammox (PD/A) granular process to address this challenge. The PD/A granular process achieved an effluent TN level of 3.7 mg/L at a low C/N ratio of 2.3. Analysis of a typical cycle showed that the partial denitrification peaked within 15 min and achieved a nitrate-to-nitrite transformation ratio of 86.9%. Anammox, which was activated from 15 to 120 min, contributed 86.2% of the TN removal. The system exhibited rapid recovery from post-organic shock, which was attributed to significant increases in protein content within TB-EPS. Microbial dispersion and reassembly were observed after coexistence of the granules, with Thauera (39.12%) and Candidatus Brocadia (1.25%) identified as key functional microorganisms. This study underscores the efficacy of PD/A granular sludge technology for treating low-C/N nitrate wastewater.

Green investor behavior and corporate green innovation: Evidence from Chinese listed companies.

Businesses embracing green innovation can encourage high-quality green economic development in addition to reducing emissions. In this paper, we use the Difference-in-Differences (DID) to investigate the influence of green investor behavior on the green innovation of companies, using the first-ever green investor investment in a company as a quasi-natural experiment. According to research, green investors have the power to accelerate corporate green innovation greatly. Three key strategies that green investors can use to do this include raising institutional investment levels, enhancing the green perception of executives, and bringing in top talent. Heterogeneity analysis shows that non-high-polluting, big, and state-owned enterprises (SOEs) are more likely to benefit from green investors' green innovation effects. Further analysis reveals that (ⅰ) green investors' influence on an enterprise's level of green innovation can help it improve its ESG ratings; (ii) green investors can encourage green innovation in source control but have little effect on green innovation in end-of-pipe treatment; (ⅲ) green investors can support both non-green and green innovation in enterprises, but have a greater influence on green innovation. This study strengthens the micro relationship between green investors and corporate green innovation. It also supports the theoretical underpinnings of corporate green innovation, which is significant for advancing green innovation, environmental protection, and high-quality economic development in emerging economies.

Functional and financial analysis of an inclined step solar desalination using phase change nanomaterials.

Recent decades have seen a shortage of water, which has led scientists to concentrate on solar desalination technologies. The present study examines the solar water desalination system with inclined steps, while considering various phase change materials (PCMs). The findings suggest that the incorporation of PCM generally enhances the productivity of the solar desalination system. Additionally, the combination of nanoparticles has been used to PCM, which is a popular technique utilized nowadays to improve the efficiency of these systems. The current investigation involves the transient modeling of a solar water desalination system, utilizing energy conservation equations. The equations were solved using the Runge-Kutta technique of the ODE23s order. The temperatures of the salt water, the absorbent plate of the glass cover, and the PCM were calculated at each time. Without a phase changer, the rate at which fresh water is produced is around 5.15 kg/m2·h. The corresponding mass flow rates of paraffin, n-PCM I, n-PCM III, n-PCM II, and stearic acid are 22.9, 28.9, 5.9, 11.9, and 73 kg/m2·h. PCMs, with the exception of stearic acid, exhibit similar energy efficiency up to an ambient temperature of around 29°. However, at temperatures over 29°, n-PCM II outperforms other PCM.

Electron Bifurcation: A Long-Hidden Energy-Coupling Mechanism.

A decade ago, a novel mechanism to drive thermodynamically unfavorable redox reactions was discovered that is used in prokaryotes to drive endergonic electron transfer reactions by a direct coupling to an exergonic redox reaction in one soluble enzyme complex. This process is referred to as flavin-based electron bifurcation, or FBEB. An important function of FBEB is that it allows the generation of reduced low-potential ferredoxin (Fdred) from comparably high-potential electron donors such as NADH or molecular hydrogen (H2). Fdred is then the electron donor for anaerobic respiratory chains leading to the synthesis of ATP. In many metabolic scenarios, Fd is reduced by metabolic oxidoreductases and Fdred then drives endergonic metabolic reactions such as H2 production by the reverse, electron confurcation. FBEB is energetically more economical than ATP hydrolysis or reverse electron transport as a driving force for endergonic redox reactions; thus, it does "save" cellular ATP. It is essential for autotrophic growth at the origin of life and also allows for heterotrophic growth on certain low-energy substrates.

Lactate oxidation is linked to energy conservation and to oxygen detoxification via a putative terminal cytochrome oxidase in Methanosarcina acetivorans.

The marine archaeon Methanosarcina acetivorans contains a putative NAD + -independent d-lactate dehydrogenase (D-iLDH/glycolate oxidase) encoded by the MA4631 gene, belonging to the FAD-oxidase C superfamily. Nucleotide sequences similar to MA4631 gene, were identified in other methanogens and Firmicutes with >90 and 35-40% identity, respectively. Therefore, the lactate metabolism in M. acetivorans is reported here. Cells subjected to intermittent pulses of oxygen (air-adapted; AA-Ma cells) consumed lactate only in combination with acetate, increasing methane production and biomass yield. In AA-Ma cells incubated with d-lactate plus [14C]-l-lactate, the radioactive label was found in methane, CO2 and glycogen, indicating that lactate metabolism fed both methanogenesis and gluconeogenesis. Moreover, d-lactate oxidation was coupled to O2-consumption which was sensitive to HQNO; also, AA-Ma cells showed high transcript levels of gene dld and those encoding subunits A (MA1006) and B (MA1007) of a putative cytochrome bd quinol oxidase, compared to anaerobic control cells. An E. coli mutant deficient in dld complemented with the MA4631 gene, grew with d-lactate as carbon source and showed membrane-bound d-lactate:quinone oxidoreductase activity. The product of the MA4631 gene is a FAD-containing monomer showing activity of iLDH with preference to d-lactate. The results suggested that air adapted M. acetivorans is able to co-metabolize lactate and acetate with associated oxygen consumption by triggering the transcription and synthesis of the D-iLDH and a putative cytochrome bd: methanophenazine (quinol) oxidoreductase. Biomass generation and O2 consumption, suggest a potentially new oxygen detoxification mechanism coupled to energy conservation in this methanogen.

Energy conservation involving 2 respiratory circuits.

Chemiosmosis and substrate-level phosphorylation are the 2 mechanisms employed to form the biological energy currency adenosine triphosphate (ATP). During chemiosmosis, a transmembrane electrochemical ion gradient is harnessed by a rotary ATP synthase to phosphorylate adenosine diphosphate to ATP. In microorganisms, this ion gradient is usually composed of [Formula: see text], but it can also be composed of Na+ Here, we show that the strictly anaerobic rumen bacterium Pseudobutyrivibrio ruminis possesses 2 ATP synthases and 2 distinct respiratory enzymes, the ferredoxin:[Formula: see text] oxidoreductase (Rnf complex) and the energy-converting hydrogenase (Ech complex). In silico analyses revealed that 1 ATP synthase is [Formula: see text]-dependent and the other Na+-dependent, which was validated by biochemical analyses. Rnf and Ech activity was also biochemically identified and investigated in membranes of P. ruminis Furthermore, the physiology of the rumen bacterium and the role of the energy-conserving systems was investigated in dependence of 2 different catabolic pathways (the Embden-Meyerhof-Parnas or the pentose-phosphate pathway) and in dependence of Na+ availability. Growth of P. ruminis was greatly stimulated by Na+, and a combination of physiological, biochemical, and transcriptional analyses revealed the role of the energy conserving systems in P. ruminis under different metabolic scenarios. These data demonstrate the use of a 2-component ion circuit for [Formula: see text] bioenergetics and a 2nd 2-component ion circuit for Na+ bioenergetics in a strictly anaerobic rumen bacterium. In silico analyses infer that these 2 circuits are prevalent in a number of other strictly anaerobic microorganisms.

Designing of an Enhanced Fuzzy Logic Controller of an Interior Permanent Magnet Synchronous Generator under Variable Wind Speed.

On account of active governmental stimulation operations in many countries, the residential production of electricity from renewable resources has increased considerably. Due to high efficiency and reliability, a recommended solution for residential wind energy conservation systems (WECS) is permanent magnet synchronous generators (PMSG). A higher torque ripple (TR), engendered by the contact of the stator with the rotor's magnetomotive force harmonics, is one foremost issue in PMSGs. To control the synchronous generator, numerous control schemes have been proposed. However, it still faces a challenge in the diminishment of the TR. An enhanced fuzzy logic controller (EFLC) in interior PMSG (IPSMG) under variable wind speed (WS) has been proposed in this article to address this challenge. Initially, the wind turbine (WT) system was designed, and the IPMSG was proposed. A hysteresis controller (HC) and fuzzy logic controller (FLC) are the two controller types utilized in this model to control TR. This methodology used the EFLC to eliminate errors during the control. By using the proper membership function (MF) for boundary selection in the WDCSO algorithm, an enhancement was executed. Better performance in TR reduction was attained by the proposed model grounded in the analysis.

Preparation of Aerogel-like Silica Foam with the Hollow-Sphere-Based 3D Network Skeleton by the Cast-in Situ Method and Ambient Pressure Drying.

Silica aerogels have incomparable advantages among thermal insulation materials because of their ultralow density and thermal conductivity, but cumbersome production processes, high cost, and low mechanical stability limit their practical application. In this study, a novel aqueous process to prepare lightweight aerogel-like silica foams (ASFoams) through the cast-in situ method and ambient pressure drying was proposed with multiblock polyurethane surfactant as the vesicle template. ASFoams possess a unique loose stacking morphology of the silica hollow sphere with a 3D network structure as the skeleton, which endues ASFoams with a low density of 0.059 g/cm3, low thermal conductivity of 36.1 mW·k-1·m-1, and pretty good mechanical properties. These properties make ASFoams a promising option for thermal insulation in industrial, aerospace, and other extreme environmental conditions. In addition, the micromorphology of ASFoams can be adjusted by changing the reaction conditions, which may provide a facile method for the preparation of a silica aerogel-like foam with adjustable microstructure.

Cold-Adapted Proteases: An Efficient and Energy-Saving Biocatalyst.

The modern biotechnology industry has a demand for macromolecules that can function in extreme environments. One example is cold-adapted proteases, possessing advantages such as maintaining high catalytic efficiency at low temperature and low energy input during production and inactivation. Meanwhile, cold-adapted proteases are characterised by sustainability, environmental protection, and energy conservation; therefore, they hold significant economic and ecological value regarding resource utilisation and the global biogeochemical cycle. Recently, the development and application of cold-adapted proteases have gained gaining increasing attention; however, their applications potential has not yet been fully developed, which has seriously restricted the promotion and application of cold-adapted proteases in the industry. This article introduces the source, related enzymology characteristics, cold resistance mechanism, and the structure-function relationship of cold-adapted proteases in detail. This is in addition to discussing related biotechnologies to improve stability, emphasise application potential in clinical medical research, and the constraints of the further developing of cold-adapted proteases. This article provides a reference for future research and the development of cold-adapted proteases.

The impact of fiscal transfer payments on energy conservation and emission reduction in China: Does the development stage matter?

Fiscal transfer payments (TRANS) are the institutional supplement of Chinese-style fiscal decentralization, which is of great significance to economic development. However, the relationship between TRANS and energy conservation and emission reduction (ECER) remains to be further discussed. Using panel data of 30 provinces in China from 2003 to 2020, this study empirically examines the impact of TRANS on energy-environmental performance (EEP) from the perspectives of influence mechanism, regional heterogeneity and nonlinearity. The results show that the influence of TRANS on ECER presents an obvious U-shaped relationship, and this influence has regional heterogeneity. At the same time, the investment-driven effect, infrastructure effect and industrial structure effect are important channels through which TRANS affect ECER. The partially linear functional coefficient models show that TRANS have different effects in different development stages. With the continuous improvement of economic level and urbanization level, the promotion effect of TRANS on ECER is more and more obvious. These results indicate that the government should increase fiscal investment in ECER, and pay attention to the development stage of different regions.

Environmental impact assessment of multi-source solid waste based on a life cycle assessment, principal component analysis, and random forest algorithm.

As a national pilot city for solid waste disposal and resource reuse, Dongguan in Guangdong Province aims to vigorously promote the high-value utilization of solid waste and contribute to the sustainable development of the Greater Bay Area. In this study, life cycle assessment (LCA) coupled with principal component analysis (PCA) and the random forest (RF) algorithm was applied to assess the environmental impact of multi-source solid waste disposal technologies to guide the environmental protection direction. In order to improve the technical efficiency and reduce pollution emissions, some advanced technologies including carbothermal reduction‒oxygen-enriched side blowing, directional depolymerization‒flocculation demulsification, anaerobic digestion and incineration power generation, were applied for treating inorganic waste, organic waste, kitchen waste and household waste in the park. Based on the improved techniques, we proposed a cyclic model for multi-source solid waste disposal. Results of the combined LCA-PCA-RF calculation indicated that the key environmental load type was human toxicity potential (HTP), came from the technical units of carbothermal reduction and oxygen-enriched side blowing. Compared to the improved one, the cyclic model was proved to reduce material and energy inputs by 66%-85% and the pollution emissions by 15%-88%. To sum up, the environmental impact assessment and systematic comparison suggest a cyclic mode for multi-source solid waste treatments in the park, which could be promoted and contributed to the green and low-carbon development of the city.

Towards energy conservation by constructing more transportation infrastructure?: An endogenous stochastic frontier analysis framework.

Whether constructing more transportation infrastructure can be helpful for the achievement of energy conservation is a long-running and debatable issue. To answer this question, the relationship between transportation infrastructure and energy efficiency must first be clarified. Nonetheless, the existence of the endogeneity problem poses a challenge to defining the relationship. In this paper, an endogenous stochastic frontier analysis method is used to investigate the influence of transportation infrastructure on energy efficiency. Based on the prefecture-city level panel data in China, we find that after addressing the endogeneity problem, the impact of transportation infrastructure on energy efficiency increases dramatically. Moreover, this impact is more pronounced in small-scale cities compared to large and medium-scale cities. Regardless of the measurement of transportation infrastructure, instrumental variable, or production function form, we get the similar conclusions, demonstrating the robustness of our findings. Additional simulation analysis shows that the energy conservation potential would be 1222-2935 million kilowatt hours if the level of transportation infrastructure could be optimized. We recommend accelerating the transportation infrastructure construction, particularly in the small-scale cities so as to boost the energy efficiency and achieve energy conservation targets.

Influence of Rotational Speed on Isothermal Piston Compression System.

An isothermal piston is a device that can achieve near-isothermal compression by enhancing the heat transfer area with a porous media. However, flow resistance between the porous media and the liquid is introduced, which cannot be neglected at a high operational speed. Thus, the influence of rotational speed on the isothermal piston compression system is analyzed in this study. A flow resistance mathematical model is established based on the face-centered cubic structure hypothesis. The energy conservation rate and efficiency of the isothermal piston are defined. The effect of rotational speed on resistance is discussed, and a comprehensive energy conservation performance assessment of the isothermal piston is analyzed. The results show that the increasing rate of the resistance work increases significantly proportional to the rotational speed, and the proportion of resistance work in the total work increases gradually and sharply. The total work including compression and resistance cannot be larger than the compression work under adiabatic conditions. The maximum rotational speed is 650 rpm.

[High-value utilization technology and approach of Chinese medicinal residues under background of "Dual Carbon"].

In recent years, the traditional Chinese medicine(TCM)industry has experienced rapid development, resulting in a significant amount of Chinese medicinal residues generated during the industrial manufacturing process. Currently, the main methods of handling Chinese medicinal residues include stacking, landfilling, and incineration, which lead to substantial resource waste and potential environmental pollution. With "carbon peak" and "carbon neutrality"( "Dual Carbon")becoming national strategic goals, the TCM industry is ushering in a new wave of "low-carbon" trends, and the high-value utilization of Chinese medicinal residues has become a breakthrough for implementing a low-carbon economy in the TCM sector. From the perspective of a low-carbon economy, this article reviewed literature in China and abroad to summarize the microbial transformation technology, enzymatic conversion technology, biomass pyrolysis, gasification, hydrothermal liquefaction, and other high-value utilization technologies for Chinese medicinal residues. It also overviewed the applications of Chinese medicinal residue in feed additives, organic fertilizers, edible mushroom cultivation substrates, preparation of activated carbon for wastewater treatment, and new energy batteries. Considering the current status of resource utilization of Chinese medicinal residues, feasible strategies and suggestions for resource development and utilization were proposed to improve the quality and efficiency of the Chinese medicinal resource industry chain and promote green development, thereby providing research ideas and theoretical basis for achieving carbon peak and carbon neutrality goals.