Mechanism of Cr(VI) removal by efficient Cr(VI)-resistant Bacillus mobilis CR3.

Cr(VI) is a hazardous environmental pollutant that poses significant risks to ecosystems and human health. We successfully isolated a novel strain of Bacillus mobilis, strain CR3, from Cr(VI)-contaminated soil. Strain CR3 showed 86.70% removal capacity at 200 mg/L Cr(VI), and a good Cr(VI) removal capacity at different pH, temperature, coexisting ions, and electron donor conditions. Different concentrations of Cr(VI) affected the activity of CR3 cells and the removal rate of Cr(VI), and approximately 3.46% of total Cr was immobilized at the end of the reaction. The combination of SEM-EDS and TEM-EDS analysis showed that Cr accumulated both on the cell surface and inside the cells after treatment with Cr(VI). XPS analysis showed that both Cr(III) and Cr(VI) were present on the cell surface, and FTIR results indicated that the presence of Cr on the cell surface was mainly related to functional groups, such as O-H, phosphate, and -COOH. The removal of Cr(VI) was mainly achieved through bioreduction, which primarily occurred outside the cell. Metabolomics analysis revealed the upregulation of five metabolites, including phenol and L-carnosine, was closely associated with Cr(VI) reduction, heavy metal chelation, and detoxification mechanisms. In addition, numerous metabolites were linked to cellular homeostasis exhibited differential expression. Cr(VI) exerted inhibitory effects on the division rate and influenced critical pathways, including energy metabolism, nucleotide metabolism, and amino acid synthesis and catabolism. These findings reveal the molecular mechanism of Cr(VI) removal by strain CR3 and provide valuable insights to guide the remediation of Cr(VI)-contaminated sites.

Optimising Complex Surgical Trays Based on PDSA Cycles.

Objective: To investigate the application of a multidisciplinary collaboration model to optimise the configuration management of orthopaedic external device sets in general hospitals. Methods: A pretest-post-test study design was used. Sixty patients who underwent unilateral total knee arthroplasty and 60 patients who underwent posterior lumbar interbody fusion between March and May 2022 were recruited as the control stage. Additionally, a total of 120 patients, 60 of each, who underwent the two procedures between September and November 2022, were recruited as the experimental stage. For the control stage, conventional external equipment management was used, and for the experimental stage, an external device management programme was implemented based on multidisciplinary collaboration with the control stage. Based on the PDSA cycle, the configuration management of orthopaedic external device sets was optimised, and the differences in collating and counting external devices, nurses' overtime in the external device stage and orthopaedic surgeon satisfaction were compared between the two stages. Results: Compared with the control stage, the collation count took less time (8.65 ± 0.25 min vs 5.37 ± 0.13 min; 13.55 ± 1.10 min vs 7.85 ± 0.82 min), the number of overtime hours was shorter (175.80 ± 12.19 min vs 96.68 ± 13.66 min) and orthopaedic surgeon satisfaction was improved (4.58 ± 0.62 vs 4.10 ± 0.68; 4.33 ± 0.73 vs 3.87 ± 0.77; 4.20 ± 0.71 vs 3.82 ± 0.71; 4.12 ± 0.69 vs 3.87 ± 0.72; 4.05 ± 0.68 vs 3.79 ± 0.68) in the experimental stage (all P < 0.05). Conclusion: Multidisciplinary collaboration offers various benefits for optimising the configuration of external device sets, such as reducing the time taken for the preoperative sorting and counting of external devices, enhancing nurses' work efficiency and improving surgeons' job satisfaction; therefore, it is worthy of reference in clinical practice.

Exploring the mechanism of enhanced Cr(VI) removal by Lysinibacillus cavernae microcapsules loaded with synthetic nano-hydroxyapatite.

In this study, nano-scale hydroxyapatite (HAP) powder was successfully synthesized from waste eggshells and combined with Lysinibacillus cavernae CR-2 to form bio-microcapsules, which facilitated the enhanced removal of Cr(VI) from wastewater. The effects of various parameters, such as bio-microcapsule dosage, HAP dosage, and initial Cr(VI) concentration on Cr(VI) removal, were investigated. Under different treatment conditions, the Cr(VI) removal followed the order of LC@HAP (90.95%) > LC (78.15%) > Free-LC (75.61%) > HAP (6.56%) > NM (0.23%) at the Cr(VI) initial concentration of 50 mg L-1. Relative to other reaction systems, the LC@HAP treatment exhibited a considerable decrease in total Cr content in the solution, with removal rates surpassing 70%. Additionally, the bio-microcapsules maintained significant biological activity after reacting with Cr(VI). Further characterization using SEM, FTIR, XPS, and XRD revealed that the Cr(VI) removal mechanisms by bio-microcapsules primarily involved biological reduction and HAP adsorption. The adsorption of Cr(III) by HAP predominantly occurred through electrostatic interactions and surface complexation, accompanied by an ion exchange process between Cr(III) and Ca(II). Hence, bio-microcapsules, created by combining L. cavernae with HAP, represent a promising emerging material for the enhanced removal of Cr(VI) pollutants from wastewater.

Effect of amino acids on biomineralization of lead ions by Aspergillus niger.

This study investigates the biomineralization of lead ions by Aspergillus niger from aqueous environments, focusing on the dynamic effects of fungal metabolism and biological components. Three biomolecules (glutamate, methionine, and lysine) were used to induce lead oxalate mineralization under lead stress. Comparative experiments were conducted to analyze the growth characteristics and Pb (II) removal ability of A. niger, as well as the morphological and structural properties of the resulting lead oxalate minerals using inductively coupled plasma atomic emission spectroscopy, X-ray powder diffraction, and scanning electron microscopy-energy dispersive spectroscopy techniques. The findings reveal that A. niger plays a crucial role in controlling the mineralization process of Pb (II), with biomineralization experiments demonstrating the specific morphogenesis of lead oxalate over time. Additionally, the inclusion of the three biomolecules in the system indirectly influenced the rate of Pb (II) removal and mineral morphology. These results contribute to a better understanding of A. niger-mediated biomineralization process of lead oxalate and suggest its potential application in the removal of Pb (II) from aqueous environments, particularly in combination with amino acids for enhanced immobilization and mineral recovery. PRACTITIONER POINTS: Fungal activity and amino acids play a crucial role in shaping lead oxalate crystals during water treatment processes. Specific amino acids can effectively delay lead oxalate recrystallization, enhancing the stability and removal efficiency of the crystals. Biomineralization mediated by fungi offers a promising and eco-friendly approach for lead removal and recovery in wastewater treatment. Exploring the influence of organic additives and fungal metabolism on crystal growth provides valuable insights for developing efficient remediation strategies. Further research on the utilization of fungi and amino acids can help with innovative and sustainable wastewater treatment technologies.

Microbial remediation mechanisms and applications for lead-contaminated environments.

High concentrations of lead (Pb) in agricultural soil and wastewater represent a severe threat to the ecosystem and health of living organisms. Among available removal techniques, microbial remediation has attracted much attention due to its lower cost, higher efficiency, and less impact on the environment; hence, it is an effective alternative to conventional physical or chemical Pb-remediation technologies. In the present review, recent advances on the Pb-remediation mechanisms of bacteria, fungi and microalgae have been reported, as well as their detoxification pathways. Based on the previous researches, microorganisms have various remediation mechanisms to cope with Pb pollution, which are basically categorized into biosorption, bioprecipitation, biomineralization, and bioaccumulations. This paper summarizes microbial Pb-remediation mechanisms, factors affecting Pb removal, and examples of each case are described in detail. We emphatically discuss the mechanisms of microbial immobilization of Pb, which can resist toxicity by synthesizing nanoparticles to convert dissolved Pb(II) into less toxic forms. The tolerance mechanisms of microbes to Pb are discussed at the molecular level as well. Finally, we conclude the research challenges and development prospects regarding the microbial remediation of Pb-polluted environment. The current review provides insight of interaction between lead and microbes and their potential applications for Pb removal.

Hexavalent chromium reduction and bioremediation potential of Fusarium proliferatum S4 isolated from chromium-contaminated soil.

Microbial remediation, utilizing reduction of Cr(VI) to Cr(III), is considered a promising method for lowering toxic environmental chromium levels. In this study, a Cr(VI)-resistant fungal strain, Fusarium proliferatum S4 (F. proliferatum), was isolated from seriously chromium-polluted soil at Haibei Chemical Plant, China. This strain for treatment chromium-containing solution resulted in 100.00%, 93%, and 74% removal at initial concentrations of 10, 30, and 50 mg L-1 Cr(VI), respectively, after 12 days of treatment in a batch mode. Contributions of different cell fractions to Cr(VI) removal were explored. The Cr(VI) removal capacity of various cell components from strong to weak was as follows: cytoplasm, cell secretions, and cell debris. Observations obtained by scanning electron microscopy and transmission electron microscopy with energy dispersive X-ray spectroscopy revealed that not only the cell surfaces but also the intracellular contents were involved Cr through adsorption, reduction, or accumulation. Fourier transform infrared spectra indicated that a large number of functional groups (amino, carbonyl, carboxyl, and phosphate groups) participated in chromium binding on the cell surface. X-ray photoelectron spectroscopy confirmed the presence of Cr on the cell surface only as Cr(III). The results have important implications for an in-depth understanding of microbial chromate reduction by F. proliferatum. This study provides an insight into the microbial Cr(VI) bioreduction efficiency, and mechanisms in the chromium-contaminated environment.

Proteomics study on immobilization of Pb(II) by Penicillium polonicum.

Lead (Pb) is widely distributed in nature and has important industrial applications, while being highly toxic. In this study, the Pb(II) biosorption and immobilization behavior of Penicillium polonicum was investigated through surface morphology observation and multiple experimental analysis. In addition, the molecular mechanism of Pb(II) immobilization was further explored through proteomics. The analysis of the removal ability of P. polonicum to Pb(II) has found that P. polonicum could remove Pb(II) up to 95% (initial 4 mM Pb(II)) in 12 d. Scanning Electron Microscope (SEM) revealed a large amount of Pb(II) adsorbed on the cell wall. Raman and Energy Disperse Spectroscopy (EDS) revealed the formation of large amounts of PbC2O4 minerals extracellularly. Field Emission High-resolution Transmission Electron Microscopy (FE-TEM) found that [Pb5(PO4)3Cl] formed on the cell surface and inside the cells. The iTRAQ technique was used to analyze the characteristics of the changes of proteins during the action between Pb(II) and P. polonicum, which further revealed the mechanism of P. polonicum against Pb(II) and biomineralization. It was found that differential proteins in terms of redox, ion binding, metabolic process and ribosome synthesis were predominant in the GO analysis. Together with some of the characterization experiments above, the mechanisms mentioned above was well explained. The up-regulated expression of related proteins involved in respiratory metabolic pathways, antioxidant stress, and degradation of intracellular hazardous substances in the P. polonicum intracellularly such as succinate dehydrogenase, ATPase and cytochrome c oxidase, could explain the high tolerance of P. polonicum to Pb(II). The up regulation of OAH was responsible for extracellular PbC2O4 production. The up regulation of proteins such as TXN and GFA promoted Pb-glutathione (Pb-GSH) complex formation. This study explores the mechanism of Pb removal by fungi from the proteomic level, and provides new ideas and ways for Pb biogeochemical research.

Efficient immobilization behavior and mechanism investigation of Pb(II) by Aspergillus tubingensis.

OBJECTIVES: To understand the mechanism of Pb(II) immobilized by Pb(II)-tolerant microbes. RESULTS: Aspergillus tubingensis isolated from the lead-zine mine was investigated through surface morphology observation and multiple experimental analysis in order to elucidate the Pb(II) biosorption and immobilization behavior. The maximum Pb(II) uptake capacity of A. tubingensis was about 828.8 mg L-1. Fourier transform-infrared spectra and environmental scanning electron microscope indicated that a large number of functional groups (carboxyl, phosphoryl and sulfydryl, etc.) participated in Pb(II) binding on the cell surface. Raman and X-ray diffraction, field emission high-resolution transmission electron microscopy and X-ray absorption fine structure investigation revealed that the Pb(II) loaded on the surface of the fungus could be transformed into PbCO3 and PbS nanocrystals. Meanwhile, Pb(II) transported into the cell would be oxidized to form lead oxide minerals (Pb2O3.333) over time. CONCLUSIONS: This study has important implications for an in-depth understanding of Pb(II) removal by A. tubingensis and provides guidance for remediating lead-polluted environment using microorganisms.

A review on mechanism of biomineralization using microbial-induced precipitation for immobilizing lead ions.

Lead (Pb) is a toxic metal originating from natural processes and anthropogenic activities such as coal power plants, mining, waste gas fuel, leather whipping, paint, and battery factories, which has adverse effects on the ecosystem and the health of human beings. Hence, the studies about investigating the remediation of Pb pollution have aroused extensive attention. Microbial remediation has the advantages of lower cost, higher efficiency, and less impact on the environment. This paper represented a review on the mechanism of biomineralization using microbial-induced precipitation for immobilizing Pb(II), including microbial-induced carbonate precipitation (MICP), microbial-induced phosphate precipitation (MIPP), and direct mineralization. The main mechanisms including biosorption, bioaccumulation, complexation, and biomineralization could decrease Pb(II) concentrations and convert exchangeable state into less toxic residual state. We also discuss the factors that govern methods for the bioremediation of Pb such as microbe characteristics, pH, temperature, and humic substances. Based on the above reviews, we provide a scientific basis for the remediation performance of microbial-induced precipitation technique and theoretical guidance for the application of Pb(II) remediation in soils and wastewater.

Removal of lead ions in an aqueous solution by living and modified Aspergillus niger.

An indigenous lead-tolerant fungal strain was isolated from lead-contaminated soil and identified as Aspergillus niger, via 18S rRNA gene sequencing. We determined the adsorption and accumulation of Pb(II) by living A. niger and the adsorption of Pb(II) via modified A. niger. This strain resisted and removed 96.21%-100% Pb(II) ranging from 2 to 8 mmol/L Pb(II). Pb-containing particles were observed outside of the cell, and lead was detected inside the cell under scanning electron microscopy and transmission electron microscopy. The process of measuring the adsorption ability of modified fungal biomass, freeze-dried, high-temperature, and alkali-treated fungal samples was analyzed; they adsorbed 25.02%, 8.76%, and 15.05% Pb(II) under 8 mmol/L Pb(II) in 43, 10, and 10 hr, respectively. These three types of modified A. niger fit the pseudo-second-order model equation well. PRACTITIONER POINTS: Isolation and identification of effective Pb(II) removal strain from the soil around Dexing lead-zinc mine. The ability of living and modified Aspergillus niger to remove Pb(II) in an aqueous environment was evaluated. Lead distributions inside and outside the cell were analyzed by SEM and TEM. Kinetic models for modified biomass adsorbing Pb(II) were made for describing adsorption process.

Removal mechanism of Pb(II) by Penicillium polonicum: immobilization, adsorption, and bioaccumulation.

Currently, lead (Pb) has become a severe environmental pollutant and fungi hold a promising potential for the remediation of Pb-containing wastewater. The present study showed that Penicillium polonicum was able to tolerate 4 mmol/L Pb(II), and remove 90.3% of them in 12 days through three mechanisms: extracellular immobilization, cell wall adsorption, and intracellular bioaccumulation. In this paper. the three mechanisms were studied by Raman, X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The results indicated that Pb(II) was immobilized as lead oxalate outside the fungal cell, bound with phosphate, nitro, halide, hydroxyl, amino, and carboxyl groups on the cell wall, precipitated as pyromorphite [Pb5(PO4)3Cl] on the cell wall, and reduced to Pb(0) inside the cell. These combined results provide a basis for additionally understanding the mechanisms of Pb(II) removal by P. polonicum and developing remediation strategies using this fungus for lead-polluted water.

[Combined Process of DNBF-O3-GAC for Nitrogen and Phosphorus and Metabolite Advanced Removal].

To improve the quality of the tailings water from a wastewater treatment plant (WWTP), a denitrification biofilter (DNBF) with a composite filler composed of a new slow-release organic-carbon source (SOC-F), sponge iron, and activated carbon was tested. Studies were conducted in the combined process of DNBF-O3-GAC to explore the efficiency of the advanced removal of nitrogen, phosphorus, and microbial metabolite by using synthetic effluent made from running water and chemicals. Corresponding comparative studies were conducted by using the secondary effluent from the WWTP. The microbial population structure in the biofilm of the denitrification biofilter was analyzed by adopting MiSeq high-throughput sequencing technologies. The results indicated that the combination process achieved high efficiency removal of nitrogen, phosphorus, and microbial metabolite. The average removal rate of NO3--N in the simulated and actual water period reached 88.87% and 79.99%, respectively; the average removal rate of TP reached 87.67% and 65.51%, respectively; and the average removal rate of UV254 reached 45.51% and 49.23%, respectively. Each processing unit had different functions. The changes in NO3--N, TN, TP, and TFe mainly occurred in the denitrification biofilter, and the removal of UV254 and the change in the three-dimensional fluorescence intensity mainly occurred in the ozone-activated carbon reactor. The cluster analysis at the genus level indicated that the denitrification system had sulfur autotrophic denitrifying bacteria and heterotrophic denitrifying bacteria. Sulfur autotrophic denitrification increased obviously in the actual water period when relatively lack of carbon sources, and the proportion of Thiobacillus increased from 7.44% to 29.62%. The complementary effect of sulfur autotrophic denitrification and heterotrophic denitrification had extended the use of the new slow-release carbon source.

A 3DBER-S-EC process for simultaneous nitrogen and phosphorus removal from wastewater with low organic carbon content.

A new process was proposed by integrating a three-dimensional biofilm electrode reactor with sulfur autotrophic denitrification and electrocoagulation within the same reactor. The results indicated that under the wastewater influent condition of NO3--N = 30 mg/L, COD = 45 mg/L, total phosphorus (TP) = 1.5 mg/L, hydraulic retention time (HRT) = 8 h, and I = 400 mA, the NO3--N and TP removal of the proposed process reached 89.8% and 83.0%, respectively. It was observed that the electrocoagulation process improved phosphorus removal, while the simultaneous existence of heterotrophic, hydrogen, sulfur and iron autotrophic denitrifying bacteria led to enhanced and stabilized nitrogen removal. The Sulfuritalea hydrogenivorans sk43H and Sulfuricella denitrificans skB26 were found as the dominant denitrifying bacteria in the electrocoagulation section and the section of biofilm electrode with sulfur filler, respectively. As compared to conventional technologies, the proposed new process can achieve simultaneous, stable and deep nitrogen and phosphorus removal from wastewater treatment plant effluent with low organic carbon content.

[Preparation and Phosphorus Removal Mechanism of Highly Efficient Phosphorus Adsorbent Mg/Al-LDO].

Aiming at the problem of phosphorus removal in water, Mg/Al-layered double hydroxides (Mg/Al-LDHs) were synthesized via optimized constant pH co-precipitation method, and highly efficient phosphorus adsorbent Mg/Al-layered double oxide(Mg/Al-LDO) was obtained when it was calcined at high temperature. Based on the adsorption characteristics of phosphorus removal, the study combined Zeta potential, X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) to analyze the changes of isoelectric point, crystal structure and functional group before and after adsorption. In addition, Mg/Al-LDO of phosphorus adsorption mechanism was discussed. The results indicated that using the optimized co-precipitation method in the conditions of Mg/Al=2:1, calcination temperature 450℃, and calcination time 2 h, the Mg/Al-LDO adsorption capacity of phosphate was the best, and the maximum adsorption capacity could reach 176.94 mg·g-1, which was basically consistent with the theoretical adsorption capacity of 191.57 mg·g-1, far higher than those of Mg/Al-LDHs and other phosphorus adsorbents. The results showed that the experimental data has the best fitting result with pseudo-second-order kinetics model. The adsorption process was consistent with Langmuir adsorption isotherm model. The results of Zeta potential, XRD and FTIR showed that phosphorus adsorption of Mg/Al-LDO was accomplished co-operatively by electrostatic attraction, anion in layer, ions exchange, and surface co-ordination.

[Effects of Temperature on the Characteristics of Nitrogen and Phosphorus Removal and Microbial Community in SCSC-S/Fe].

In order to investigate the effect of temperature on the cellulose-degrading bacteria and denitrifying bacteria, the denitrification and phosphorus removal of solid carbon source of cellulose corncob+sulfur/sponge iron nitrogen and phosphorus removal composite system, abbreviated as SCSC-S/Fe, was analyzed under different temperature conditions, and the surface structure and microbial properties of corncob before and after reaction were analyzed by scanning electron microscope (SEM) and MiSeq high-throughput sequencing technologies. The results indicated that when temperature increased from 15, 20, 25 to 30℃, the average TN removal rate of the system increased from 78.88% to 92.70%, the average removal rate of TP increased from 82.58% to 89.15%;microbial properties showed that the surface reaction after corncob was dominated by spherical and rod-shaped microorganisms; the proportion of cellulose-degrading bacteria was 11.01% higher at 30℃ than 20℃, and the proportion of denitrifying bacteria decreased by 21.26%. It can be seen that the cellulose -degrading bacteria were more sensitive to the temperature than the denitrification bacteria, and more obviously affected by the temperature.

[Improving Nitrogen and Phosphorus Removal from Reclaimed Water Using a Novel Sulfur/Iron Composite Filler].

In order to improve the ability of denitrification and phosphorus removal from reclaimed water, a novel composite filler was prepared using sulfur powder and sponge iron powder, and a comparative experiment was constructed at different HRT(hydraulic retention time) and C/N(carbon-nitrogen ratio) conditions between the novel filler and the composite filler. The results showed that the efficiency of nitrogen and phosphorus removal on the novel filler was higher than that on the grain filler (more than 30% higher at HRT=4 h and C/N=1). Moreover, based on the 16S rRNA gene clone library, the denitrification system in the two reactors included sulfur autotrophic denitrification bacteria and heterotrophic denitrification bacteria, while the proportion of sulfur autotrophic denitrification bacteria in the novel filler system was higher. The dominant bacteria in the novel filler and composite filler were Sulfurimonas and Acinetobacter, respectively.

Impact of operating condition on the denitrifying bacterial community structure in a 3DBER-SAD reactor.

Two main operating parameters (influent C/N ratio and electric current intensity) were examined for their impacts on the denitrifying bacterial community structure in an integrated system of three-dimensional biofilm-electrode reactor and sulfur autotrophic denitrification (3DBER-SAD). It was found that genus ß-proteobacteria played a leading role under different operating conditions. The influent C/N ratio illustrated a great impact on denitrifying bacteria diversity. When the C/N ratio decreased from 1.07 to 0.36, the Shannon-Wiener index and Simpson index increased from 2.44 to 2.71 and from 0.89 to 0.92, respectively, while the proportion of heterotrophic denitrifying bacteria Thauera decreased from 61.4 to 21.1%, and the sulfur autotrophic denitrifying bacteria (e.g., genus Sulfuricella and Thiobacillus denitrificans) increased from 3.5 to 19.3%. In terms of the impact of electric current intensity, the Shannon-Wiener index and Simpson index decreased from 2.71 to 2.63 and from 0.92 to 0.90, respectively, as the current intensity increased from 60 to 400 mA.

[Feasibility of 3BER-S Process for the Deep Denitrification in Synch with the Removal of PAEs from Reclaimed Water].

In order to investigate the feasibility of deep denitrification and simultaneous removing phthalate esters (PAEs) in the process of reclaimed water treatment uses three-dimensional biofilm-electrode reactor coupled with sulfur autotrophic deep denitrification technology (3BER-S), the technological characteristics and mechanisms were analyzed based on determining the static adsorption capacity of biofilm cultured active carbon fillers in 3BER-S reactor together with the operation results of dynamic denitrification and simultaneous PAEs removing. The results showed that the average adsorption rates of DBP, DEHP were 85.84% and 97.12% in the biofilm cultured active carbon fillers, the equilibrium adsorption capacities were 0.1426 mg x g(-1) and 0.162 mg(-1) and the time spans of reaching adsorption saturation were 120 min and 60 min, respectively; The existence of PAEs had no obvious effect on denitrification, the reactor effluent concentration of TN was in range of 1-2 mg x L(-1) before and after the addition of PAEs, and the average removal rate of TN reached above 94%; 3BER-S denitrification system showed significant ability in removing PAEs, leading to effluent concentrations of DBP and DEHP of no more than 6 microg x L(-1) with removal rates of above 96%; this was due to the synergistic effect of absorption, biodegradation and electrochemistry. After treatment with 3BER-S technology, DBP and DEHP in simulative municipal secondary effluent met the regulated limitation of The Reuse of Urban Recycling Water Quality Standard for Groundwater Recharge (GB/T 19772-2005).

An integrated process of three-dimensional biofilm-electrode with sulfur autotrophic denitrification (3DBER-SAD) for wastewater reclamation.

A three-dimensional biofilm-electrode reactor (3DBER) was integrated with sulfur autotrophic denitrification (SAD) to improve nitrogen removal performance for wastewater reclamation. The impacts of influent carbon/nitrogen (C/N) ratio, electric current, and hydraulic retention time (HRT) were evaluated. The new process, abbreviated as 3DBER-SAD, achieved a more stable denitrification compared to the recently studied 3DBER in literature. Its nitrogen removal improved by about 45 % as compared to 3DBER, especially under low C/N ratio conditions. The results also revealed that the biofilm bacteria community of 3DBER-SAD contained 21.1 % of the genus Thauera, 19.3 % of the genus Thiobacillus and Sulfuricella, as well as 5.3 % of the genus Alicycliphilus, Pseudomonas, and Paracoccus. The synergy between these heterotrophic, sulfur autotrophic, and hydrogenotrophic denitrification bacteria was believed to cause the high and stable nitrogen removal performance under various operating conditions.

Equilibrium and kinetic studies on biosorption of Pb(II) by common edible macrofungi: a comparative study.

In this work, we studied the natural bioaccumulation and biosorption of Pb(II) in several common edible macrofungi. The macrofungi include the following species: Lentinus edodes, Pleurotus eryngii, Flammulina velutipes, Hypsizygus marmoreus, and Agrocybe cylindracea. The present analysis of Pb(II) revealed distinct capabilities of metal accumulation among individual species. Moreover, the natural concentrations of lead did not reach a health risk level when cultivated in uncontaminated soil. In the biosorption experiment by edible macrofungi, we found that the equilibrium data of living sporocarp (P. eryngii and H. marmoreus) and the homogenate of L. edodes and F. velutipes fit the Freundlich model well. Other data samples exhibited a better fit to the Langmuir model. The edible macrofungi showed a higher lead removal capacity than did other biosorbents. Furthermore, the pseudo-second-order kinetics model exhibited the best fit to the biosorption processes. The effectiveness of edible macrofungi as biosorbents for Pb(II) was confirmed.