Anaerobic System Research Articles

Anaerobic Catalyst Design for Alcohol Oxidation: Fine‐Tuning Copper/TEMPO with Bipyridine Proportions

In this study, we investigate the indirect electro‐oxidation of benzyl alcohol using the Copper/TEMPO catalytic system, which combines copper complexes with 2,2,6,6‐tetramethylpiperidin‐1‐oxyl (TEMPO) in an anaerobic medium. We reexamine the impact of bpy ligand proportions, exploring ratios of 1:1, 2:1, 3:1, and 4:1 on catalytic activity. Cyclic voltammetry and visible spectroscopy reveal distinct electrochemical characteristics and complex formations at different bpy ratios. Simulations uncover intricate energy equilibria involving ion coordination, varying with oxidation state and bpy proportion. Theoretical and experimental spectra align, supporting the proposed structures. The Brønsted base, triethylamine (TEA), essential in this anaerobic system, shows different voltammetric profiles with each ligand ratio, revealing key interactions with bpy complexes. In the presence of benzyl alcohol, the 1:1 and 2:1 ratios exhibit indirect catalytic activity, with the 2:1 ratio yielding significantly higher current densities. This establishes a new optimal condition where [Cu(bpy)₂]²⁺ formed in a 2:1 stoichiometry demonstrates superior activity with a lower redox potential, while maintaining labile coordination points for necessary interactions. Theoretical results also indicate weaker TEMPO coordination to [Cu(bpy)₂]²⁺.

Effect of 12 weeks of selective cardiorespiratory endurance and plyometrics training on 800-meter rural collegiate athletes: a randomised controlled trial

IntroductionThe 800-meter race is a middle-distance run where both anaerobic and aerobic energy systems contribute significantly. The purpose of the present study was to determine the effects of 12 weeks of selective plyometrics training in addition to their regular cardiorespiratory endurance training on the running performance in 800-meterrural collegiate athletes.MethodsA total of 110 healthy volunteer rural collegiate 800-meter athletes were randomly selected based on the inclusion and exclusion criteria. Participants were randomly allocated into two equal groups (group A and group B). Group A received only conventional training, including cardiorespiratory endurance training (CON), while group B received plyometric training combined with conventional training, including cardiorespiratory endurance training (PLYO). Statistical analyses used a one-way ANOVA with post hoc testing applied between all the parameters within the groups, and an unpaired t-test was used to compare post-training values between the CON and PLYO groups.ResultsGroup A’s mean age (years), weight (kg), height (cm), BMI (kg/m2), and pulse (beat/min) were 19.22 (1.53), 60.68 (10.47), 170.4 (6.55), 20.88 (3.48), and 83.78 (9.74), respectively, and Group B’s were 19.48 (1.18), 63.16 (9.31), 171.8 (5.16), 21.37 (2.80), and 86.22 (11.69), respectively.ConclusionsThe current study’s findings indicate that 12 weeks of selective plyometric training has a significant impact in enhancing anaerobic power and a substantial effect on improving the 800-meter running time of rural collegiate athletes, but had no impact on VO2 max.

Deciphering the role of biochar pseudocapacitance strengthening in promoting syntrophic methanogenesis: Microbial capacitance-tropism in propionate metabolism

The redox functional groups of biochar can act as pseudocapacitance, alleviating acid accumulation and facilitating electron transfer in anaerobic digestion. Fe modification further enhances its pseudocapacitance properties. However, the specific role of pseudocapacitance strengthening in the electron transfer of volatile fatty acid syntrophic methanogenesis, as well as the factors inducing the enrichment behavior and metabolic mechanisms of microbes on its surface, remain unclear. In this study, experiments using acetate and propionate as substrates were conducted with the addition of biochar and electro-enhanced biochar, while 16S rRNA gene amplicon sequencing and metagenomic analysis were employed to investigate the underlying mechanisms. The results demonstrate that strengthening biochar’s pseudocapacitance significantly facilitates the electron shunt by accepting electrons, accelerating NADH/NAD+ conversion and ATP synthesis. This further promotes the oxidative degradation of propionate and acetate through the methylmalonyl-CoA (MMC) and syntrophic acetate oxidation (SAO) pathways. During methanogenesis, biochar directly transfers electrons to methanogens, with the strengthened pseudocapacitance further accelerating electron transfer through the CO2 reduction pathway and specifically promoting the methanation of propionate rather than acetate. Moreover, during propionate metabolism, Coprothermobacter and Methanosarcina exhibit capacitance-tropism in their enrichment on biochar, serving as key functional contributors to the biochar-microbial aggregates. These findings provide valuable insights for selecting exogenous materials in engineering applications to alleviate acid accumulation in anaerobic digestion systems.

Strategies for enriching targeted sulfate-reducing bacteria and revealing their microbial interactions in anaerobic digestion ecosystems

Deciphering relationships between sulfate-reducing bacteria (SRB) and other microorganisms is crucial for stable operation of anaerobic digestion systems when treating sulfate-containing wastewater. However, few studies have differentiated the incomplete oxidizing SRB (IO-SRB) and complete oxidizing SRB (CO-SRB) in anaerobic digestion ecosystems. Four ethanol-fed bioreactors were operated under two operational modes (sequencing batch reactor, SBR; and continuous-flow reactor, CFR) and two chemical oxygen demand (COD) to sulfate ratios (1 and 2) to systematically explore strategies for enriching IO-SRB and/or CO-SRB and their microbial interactions with other microorganisms. Compared to SBRs, CFRs could enhance sulfate removal and demonstrated higher microbial activities in sulfate and ethanol degradation. IO-SRB competed with ethanol oxidizing bacteria in all reactors, and IO-SRB's contribution to ethanol degradation increased from 62.9 %-67.1 % to 69.0 %-82.1 % as the COD/sulfate ratio decreased from 2 to 1. Moreover, CO-SRB competed acetotrophic methanogens exclusively in CFRs, as CO-SRB could not be efficiently enriched in SBRs. Low COD/sulfate ratios facilitated the enrichment of Desulfococcus (CO-SRB), and the CFR operational mode further strengthened its enrichment. Additionally, hydrogenotrophic SRB outperformed hydrogenotrophic methanogens in all four reactors. In general, IO-SRB and CO-SRB possessed distinct microbial interactions with methanogens, with potential syntrophic relationships between IO-SRB and acetotrophic methanogens while competitive relationships between CO-SRB and acetotrophic methanogens.

Regulating the porous properties of polyaniline enhances the electron transfer process and methane production during anaerobic wastewater treatment

Conductive materials are known to enhance methane production in anaerobic treatment process by facilitating direct interspecies electron transfer (DIET). However, the role of the porous structure of conductive materials in electron transfer remains underexplored. Polyaniline (PANI) was used as conductive materials in this study due to its easily controlled porosity, investigating how surface area and pore size affect methane production. It was demonstrated that the porosity of PANI is an important factor affecting methane production by anaerobic sludge. Methane production rate of 41.2 mL/h was achieved with the high-porosity PANI, which was ~73.2% higher than the control group. The porous PANI enhanced the electric field in the anaerobic sludge, facilitating the enrichment of electrogenic bacteria and archaea. In the anaerobic system supplemented with porous PANI, the maximum accumulation of acetic acid reached 3.72 mM. The abundance of electroactive bacteria Clostridium involved in DIET increased by 2.13-fold, while the abundance of electroactive archaea Methanosaeta and Methanobacterium, which also participate in DIET, rose by 1.55-fold. The porous structure of PANI promotes DIET and enhances aceticlastic methanogenesis.

Exponential Functions Permit Estimation of Anaerobic Work Capacity and Critical Power from Less than 2 Min All-Out Test

The Critical Power Model (CPM) is key for assessing athletes’ aerobic and anaerobic energy systems but typically involves lengthy, exhausting protocols. The 3 min all-out test (3MT) simplifies CPM assessment, yet its duration remains demanding. Exponential decay models, specifically mono- and bi-exponential functions, offer a more efficient alternative by accurately capturing the nonlinear energy dynamics in high-intensity efforts. This study explores shortening the 3MT using these functions to reduce athlete strain while preserving the accuracy of critical power (CP) and work capacity (W′) estimates. Seventy-six competitive cyclists and triathletes completed a 3MT on a cycle ergometer, with CP and W′ calculated at shorter intervals. Results showed that a 90 s test using the bi-exponential model yielded CP and W′ values similar to those of the full 3MT. Meanwhile, the mono-exponential model required at least 135 s. Bland–Altman and linear regression analyses confirmed that a 120 s test with the mono-exponential model reliably estimated CP and W′ with minimal physical strain. These findings support a shortened, less-demanding 3MT as a valid alternative for CPM assessment.

Electron Transfer Improved by Nanoscale Zero-Valent Iron to Enhance Sulfate Reduction of the Anaerobic System under a Low Chemical Oxygen Demand-to-Sulfate Ratio

Electron Transfer Improved by Nanoscale Zero-Valent Iron to Enhance Sulfate Reduction of the Anaerobic System under a Low Chemical Oxygen Demand-to-Sulfate Ratio

Using phragmites australis biochar bio-augmented with actinomycetes for enhancing UASB reactor performance: A field study

Anaerobic processes are a cost-effective and sustainable method for wastewater treatment due to their lower energy demand and potential for biogas-high methane recovery. The up-flow anaerobic sludge blanket reactor system (UASB) is a commonly used technology. This study aimed to evaluate the performance of UASB reactors for handling the wash water from the buffalo shed, with a comparison of traditional UASB to UASB modified reactor by incorporation of immobilized biochar with and without bioaugmentation of a bacterial species with documented anaerobic capabilities. The investigation was conducted as a pilot project at the Suez Canal University Veterinary Experimental Farm in Ismailia, Egypt. Adding Streptomyces hydrogenans S11-immobilized Phragmites australis biochar to the USAB reactor increased removal efficiency, even at high influent loadings. The findings demonstrated that the traditional UASB reactor attained removal efficiency for COD, BOD5, TSS, TDS, color, and turbidity of 81.0 %, 75.0 %,80.0 %, 80.0 %, 70.0 %, and 70.0 % respectively, and biogas production of (0.025 mL biogas/mg COD removed).In comparison, the modified UASB reactor attained COD, BOD5, TSS, TDS, Color, and Turbidity removal efficiencies of 93.0 %, 91.5 %,90.3 %, 91.10 %, 85 %, and 80.0 %, respectively. The biogas production reached (0.037 mL biogas/mg COD removed). The removal efficiencies of the measured parameters were statistically analyzed, and this analysis indicated that the efficiency of the modified reactor was enhanced dramatically compared to the traditional system. Hence, this work demonstrates an efficient approach for treating buffalo wastewater.

Insights into the Acute Stress of Glutaraldehyde Disinfectant on Short-Term Wet Anaerobic Digestion System of Pig Manure: Dose Response, Performance Variation, and Microbial Community Structure

The outbreak of epidemics such as African swine fever has intensified the use of disinfectants in pig farms, resulting in an increasing residual concentration of disinfectants in environmental media; however, the high-frequency excessive use of disinfectants that damage pig farm manure anaerobic fermentation systems and their mechanisms has not attracted enough attention. Especially, the complex effects of residual disinfectants on anaerobic fermentation systems for pig manure remain poorly understood, thus impeding the application of disinfectants in practical anaerobic fermentation systems. Herein, we explored the effects of glutaraldehyde disinfectant on methane production, effluent physicochemical indices, and microbial communities in a fully automated methanogenic potential test system (AMPTSII). The results show that adding glutaraldehyde led to remarkable alterations in methane production, chemical oxygen demand (COD), volatile solids (VS), and polysaccharide and phosphorus concentrations. During the anaerobic process, the production of methane displayed a notable decrease of 5.0–98% in all glutaraldehyde treatments, and the trend was especially apparent for treatments containing high levels of glutaraldehyde. Comparisons of the effluent quality showed that in the presence of 0.002–0.04% glutaraldehyde, the COD and total phosphorus (TP) increased by 12–310% and 15–27%, respectively. Moreover, the addition of 0.01–0.08% glutaraldehyde decreased the ammonium (NH4+-N) concentration and VS degradation rate by 7.7–15% and 4.9–26.2%. Furthermore, microbiological analysis showed that the glutaraldehyde treatments had adverse effects on the microbial community. Notably, certain functional bacteria were restrained, as highlighted by the decreases in relative abundance and microbial diversity by 1.3–17% and 0.06–21%, respectively. This study provides a theoretical basis for the rational use of disinfectants in anaerobic fermentation systems.

Lipase pretreatment enhances biochar‐assisted anaerobic digestion of food waste

AbstractAnaerobic digestion is a promising technology for the treatment of food waste (FW) but it requires optimization to improve its performance. This study investigated whether combining the addition of biochar with lipase pretreatment could improve the anaerobic digestion of FW. The results showed that biochar stimulated the release of soluble substances, resulting in an increase in the methane yield of groups with added biochar by 16.24% to 19.36% in comparison with the group without biochar. Lipase pretreatment substantially shortened the fermentation time required to complete the anaerobic digestion, from 15 to 9 days. Lipase pretreatment further improved microbial abundance and promoted the enrichment of functional microbes in the anaerobic digestion of FW mediated by biochar. It also changed the methane production pathway from acetotrophic to hydrogenotrophic, thereby ensuring the stability of the anaerobic digestion system in the presence of a high ammonia nitrogen concentration.

Acclimatation of Microbial Biomass to Effluents From a Swine Slaughterhouse in Batch Reactors

Objective: To evaluate the acclimatization of microbial biomass in sequential reactors to optimize the treatment of wastewater from pig slaughterhouses. Theoretical framework: The meat industry generates highly contaminated wastewater. Biological treatments, such as aerobic and anaerobic systems, are more efficient and sustainable than physicochemical ones. Materials and methods: Industrial effluents were collected in a pig slaughterhouse and then characterized. The microbial biomass was collected from the same slaughterhouse and was subjected to an acclimatization process in a sequential batch reactor. Results and discussion: The results showed that the wastewater from the pig slaughterhouse had high levels of BOD, COD and suspended solids, exceeding the limits established by local regulations. During the acclimatization process, the microbial biomass demonstrated a gradual improvement in its COD removal capacity, reaching efficiencies greater than 70%. The positive correlation observed between volumetric organic load and organic matter removal efficiency indicates that acclimated biomass has a greater capacity to treat effluents with high levels of organic load. Research implications: Biomass acclimatization is essential to improve the efficiency of biological treatment in slaughterhouse effluents, reducing its environmental impact and the need for costly treatments. Value/originality: This study proposes a more sustainable and efficient solution for the treatment of slaughterhouse wastewater, highlighting the importance of biomass acclimatization.

Growth substrate limitation enhances anaerobic arsenic methylation by Paraclostridium bifermentans strain EML.

Microbial arsenic methylation is established as a detoxification process under aerobic conditions (converting arsenite to monomethylated arsenate) but is proposed to be a microbial warfare strategy under anoxic conditions due to the toxicity of its main product, monomethylarsonous acid (MMAs(III)). Here we leveraged a paddy soil-derived anaerobic arsenic methylator, Paraclostridium bifermentans strain EML, to gain insights into this process. Strain EML was inoculated into a series of media involving systematic dilutions of Reinforced Clostridial Broth (RCB) with 25 µM arsenite to assess the impact of growth substrate concentration on arsenic methylation. Growth curves evidenced the sensitivity of strain EML to arsenite, and arsenic speciation analysis revealed the production of MMAs(III). Concentrations of MMAs(III) and arsenic methylation gene (arsM) transcription were found to be positively correlated with RCB dilution, suggesting that substrate limitation enhances arsM gene expression and associated anaerobic arsenic methylation. We propose that growth substrate competition among microorganisms may also contribute to an increase in anaerobic arsenic methylation. This hypothesis was further evaluated in an anaerobic co-culture system involving strain EML and either wild-type Escherichia coli K-12 MG1655 (WT) or E. coli expressing the MMAs(III)-resistance gene (arsP) (ArsP E. coli). We observed increased MMAs(III) production in the presence of E. coli than its absence and growth inhibition of WT E. coli to a greater extent than ArsP E. coli, presumably due to the MMAs(III) produced by strain EML. Collectively, our findings suggest an ecological role for anaerobic arsenic methylation, highlighting the significance of microbe-microbe competition and interaction in this process.IMPORTANCEMicrobial arsenic methylation is highly active in rice paddy fields under flooded conditions, leading to increased accumulation of methylated arsenic in rice grains. In contrast to the known detoxification process for aerobic arsenic methylation, the ecological role of anaerobic arsenic methylation remains elusive and is proposed to be an antibiotic-producing process involved in microbial warfare. In this study, we interrogated a rice paddy soil-derived anaerobic arsenic-methylating bacterium, Paraclostridium bifermentans strain EML, to explore the effect of growth substrate limitation on arsenic methylation in the context of the microbial warfare hypothesis. We provide direct evidence for the role of growth substrate competition in anaerobic arsenic methylation via anaerobic prey-predator co-culture experiments. Moreover, we demonstrate a feedback loop, in which a bacterium resistant to MMAs(III) enhances its production, presumably through enhanced expression of arsM resulting from substrate limitation. Our work uncovers the complex interactions between an anaerobic arsenic methylator and its potential competitors.

The kinetics of a two-stage completely stirred tank reactor for treating tofu wastewater by anaerobic digestion

ABSTRACT Tofu wastewater is an inevitable by-product of the bean curd production process. In this study, we used a two-stage continuous stirred tank reactor (CSTR) to treat tofu wastewater. The kinetic analysis of two CSTR reactors was conducted utilizing the material accounting model, microbial accounting model, and first-order kinetic model. The results demonstrated that the methane production coefficient of reactor 1 was 0.00573 LCH4·mg−1 greater than that of reactor 2, which is 0.00533 L CH4·mg−1. The first-order kinetic constants of reactor 1 were poorer than those of reactor 2, and their values are 0.15700 d−1 and 0.11574 d−1, respectively. The microbial yield coefficients of reactors 1 and 2 were 0.009648 and 0.060704, respectively. Under different organic loading rates, the average microbial concentrations were 25.24000 and 2.706667 mg·L−1 for reactors 1 and 2, respectively. The operational performance of the two-stage CSTR anaerobic digestion system was evaluated in order to design a novel and unique method as well as provide a new perspective for enhancing the performance of anaerobic digestion.

Comparative analysis of anaerobic degumming effects on different bast fibers from the angle of enzyme activity and microbial community structure

Bast fiber textiles are becoming more and more popular, and degumming is a key process to obtain fiber. However, the more widely used degumming methods currently have a high level of pollution, which has become a primary problem restricting the development of the textile industry. Therefore, this study developed a continuous-flow anaerobic biological degumming system for bast fibers (Ramie and Hemp), with a self-developed spiral symmetry stream anaerobic bioreactor (SSSAB) as the core. The basic indicators of the degumming systems’ operation were analyzed, including pH, COD (Chemical Oxygen Demand), weight loss ratio, fineness, and breaking strength. pH and COD results indicated that the systems are operated continuously and steadily. The breaking strength of Ramie fiber and Hemp fiber were found about 4–6.5 cN/dtex and 2–4 cN/dtex, respectively, which meet subsequent spinning needs. The weight loss ratio of Ramie fiber (maximum value 27.27%) obtained by this anaerobic degumming method was generally higher than that produced by the traditional degumming method. SEM (Scanning Electron Microscopy) found the bast fibers current degumming time was too long and a lot of microorganisms adhered to the surface of the fibers. Enzyme activities testing in different fiber degumming systems found that the Ramie fiber degumming system has a higher cellulase activity than the Hemp fiber degumming system. From the perspective of community structure, it was believed that there were significant differences in microbial flora between Ramie and Hemp degumming systems, but there was no significant difference in archaea between them. This not only explored the adaptability of anaerobic continuous flow biological degumming system varieties but also provided theoretical guidance for enterprises to degum different bast fibers.

Changing Horses in Midstream: Modern Pentathlon After the 2024 Olympic Games.

The decision of the Union Internationale de Pentathlon Moderne to replace horse riding with Obstacle after the 2024 Olympic Games challenges training, testing, and recovery management in Modern Pentathlon. This commentary discusses physiological, technical, and tactical effects of rule changes in the 5 disciplines with a specific focus on the new discipline Obstacle. Modern Pentathlon requires athletes to develop specific endurance capacities relying on both the aerobic and anaerobic systems while simultaneously increasing lower- and upper-body strength capabilities. In addition, movements must be repeatedly executed in an explosive and precise manner. Running and swimming must be fast but economical. Swapping from horse riding to Obstacle will prioritize the explosive strength of the upper extremities and core while keeping high levels of endurance and precision in swimming, fencing, and shooting. Moreover, condensing the Modern Pentathlon competition to a 90-minute television-friendly format enables more competitions in the future. Athletes and coaches will thus also need to develop and maintain effective individual peri-exercise routines (before, during, and after the competition) to successfully meet the resulting tactical and physical challenges of the new format. This commentary aims to stimulate the discussion on the effect of the Union Internationale de Pentathlon Moderne's decisions to replace riding with the new Obstacle discipline and implement a more television-friendly format with a focus on physiological, technical, and tactical aspects.

Optimization based process modeling of an anaerobic membrane bioreactor system: Application to swine wastewater

To maintain current levels of consumption in the economy with the dwindling supply of non-renewable material and energy, alternative resource streams more traditionally viewed as waste streams must be considered. Fermentation of high-strength wastewaters is one such pathway that allows for the recovery of energy, nitrogen, phosphorus, and carbon compounds. Anaerobic membrane bioreactors (AnMBRs) are an emerging technology that allow for the digestion of wastewater in a much smaller footprint than traditional anaerobic digesters. Adoption of this technology into industry has been limited by membrane capital and cleaning costs, but these costs may be offset through the recovery of valuable products. To evaluate the viability of AnMBR technology in the context of swine wastewater treatment, an optimization-based process model built upon Anaerobic Digestion Model No. 1 (ADM1) has been developed. Modeling results show that a swine wastewater stream provides potential for net positive energy generation from the AnMBR system in most cases. Sensitivity analyses around important variables were conducted to determine focus areas for future research into AnMBR technology and evaluate the robustness of the model to microbial variables that may change with different microbial communities.

A Novel Method to Predict Carbohydrate and Energy Expenditure During Endurance Exercise Using Measures of Training Load.

Sports nutrition guidelines recommend carbohydrate (CHO) intake be individualized to the athlete and modulated according to changes in training load. However, there are limited methods to assess CHO utilization during training sessions. We aimed to (1) quantify bivariate relationships between both CHO and overall energy expenditure (EE) during exercise and commonly used, non-invasive measures of training load across sessions of varying duration and intensity and (2) build and evaluate prediction models to estimate CHO utilization and EE with the same training load measures and easily quantified individual factors. This study was undertaken in two parts: a primary study, where participants performed four different laboratory-based cycle training sessions, and a validation study where different participants performed a single laboratory-based training session using one of three exercise modalities (cycling, running, or kayaking). The primary study included 15 cyclists (five female; maximal oxygen consumption [ O2max], 51.9 ± 7.2mL/kg/min), the validation study included 21 cyclists (seven female; O2max 53.5 ± 11.0mL/kg/min), 20 runners (six female; O2max 57.5 ± 7.2mL/kg/min), and 18 kayakers (five female; O2max 45.6 ± 4.8mL/kg/min). Training sessions were quantified using six training load metrics: two using heart rate, three using power, and one using perceived exertion. Carbohydrate use and EE were determined separately for aerobic (gas exchange) and anaerobic (net lactate accumulation, body mass, and O2 lactate equivalent method) energy systems and summed. Repeated-measures correlations were used to examine relationships between training load and both CHO utilization and EE. General estimating equations were used to model CHO utilization and EE, using training load alongside measures of fitness and sex. Models were built in the primary study and tested in the validation study. Model performance is reported as the coefficient of determination (R2) and mean absolute error, with measures of calibration used for model evaluation and for sport-specific model re-calibration. Very-large to near-perfect within-subject correlations (r = 0.76-0.96) were evident between all training load metrics and both CHO utilization and EE. In the primary study, all models explained a large amount of variance (R2 = 0.77-0.96) and displayed good accuracy (mean absolute error; CHO = 16-21g [10-14%], EE = 53-82kcal [7-11%]). In the validation study, the mean absolute error ranged from 16-50g [15-45%] for CHO models to 53-182kcal [9-31%] for EE models. The calibrated mean absolute error ranged from 9-20g [8-18%] for CHO models to 36-72kcal [6-12%] for EE models. At the individual level, there are strong linear relationships between all measures of training load and both CHO utilization and EE during cycling. When combined with other measures of fitness, EE and CHO utilization during cycling can be estimated accurately. These models can be applied in running and kayaking when used with a calibration adjustment.

Gender-Specific Physiological Profiles and Performance Metrics in Young Elite Table Tennis Players

Table tennis requires a combination of anaerobic and aerobic energy systems, agility, short reaction times, and precise motor skills. The aim of this study is to investigate gender-specific physiological profiles and performance measures in young elite table tennis players. The objectives are to identify key physical and anthropometric attributes contributing to table tennis performance, compare these attributes between male and female athletes, and develop targeted training recommendations. The study involved sixteen players (8 males and 8 females) within the age range of 10 to 18 years who train regularly at Istanbul Pendik Sports Hall. Inclusion criteria required training at least three times per week and participating at championship levels. Anthropometric measurements were taken using a Seca 220R stadiometer and a Seca 710R weighing scale, with body fat percentage estimated via a Tanita scale. Performance tests included vertical jump height (Witty Microgate device), reaction times (custom device), and heart rates (Activio Sport System). Assessments were carried out between 4:00 PM and 6:00 PM. Male athletes had higher mean values in height (159.00 ± 13.29 cm), weight (50.00 ± 12.06 kg), and vertical jump height, whereas female athletes had better reaction times (1.17 ± 0.14 seconds). No statistically significant differences were found in body fat percentage and mean heart rate. t-Tests revealed that gender differences in most performance metrics were not statistically significant, but correlation analysis showed statistically significant relationships between various physical characteristics and performance outcomes (p<0.05). As a result, physical fitness and reaction time are crucial for table tennis performance. Tailored training programs should focus on these attributes to enhance performance in young elite players. Future studies should follow these metrics longitudinally to understand their impact on competitive success.

Hexanoic acid production from anaerobic fermentation of Chinese cabbage waste with exogenous lactic acid as electron donor

The lack of electron donors is one of the key factors hindering hexanoic acid production from anaerobic fermentation. In this study, three different types of lactic acids were supplemented as exogenous electron donors to the anaerobic fermentation system of Chinese cabbage waste (CCW). The yields of hexanoic acid in the reactors supplemented with CCW lactic acid pre-fermentation broth (PFB), lactic acid diluent (LAD) and chemical lactic acid (LA) were 6996.8 mg COD/L, 4534.8 mg COD/L and 6777.1 mg COD/L, respectively. Compared with the reactor supplemented with LA, the electron efficiency of hexanoic acid in reactor supplemented with PFB increased by 188 %. Supplementing PFB shifted the microbial communities towards a direction favorable to hydrolysis and chain elongation, thereby facilitating the synthesis of hexanoic acid.

Metabolic mechanisms of carbon and nitrogen interactions during anaerobic digestion of coal

There was limited research on the impact of nitrogen metabolism in the process of methane production with coal, even if carbon and nitrogen metabolism were closely interconnected. Lignite was the source of carbon and nitrogen in anaerobic digestion system. The relationship between carbon and nitrogen metabolism was systematically discussed during the anaerobic digestion process. The results showed that phenolic carbon or ether carbon (C-O), pyridine-type nitrogen (N-6) and nitrogen oxide compound (N-X) in coal were decomposed under the action of Macellibacteroides, Sphaerochaeta and Trichococcus in the hydrolysis stage, respectively. In the acidogenesis stage, the stress of volatile fatty acids and ammonia produced by dissolved organic matter under the action of Syner-01 and Sphaerochaeta on hydrogenotrophic and acetoclastic methanogens was alleviated during the nitrogen cycle. In the acetogenesis stage, acetic acid produced from the decomposition of organic acids and alcohols by Synergistaceae and Sedimentibacter was competed by denitrifying bacteria and acetogenic methanogens. In the methanogenesis stage, CO2 was reduced by Methanobacterium and Methanoculleus to produce CH4, while acetic acid was decomposed by Methanosaeta to produce CH4. And methyl substances were generated into CH4 by Methanosarcina and Methanofastidiosum. This understanding will provide a basis for strengthening the favorable factors in biomethane production.