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Microbiologically induced calcite precipitation (MICP) technology shows potential for remediating heavy metal pollution; however, the underlying mechanism of heavy metal mineralization is not well-understood, limiting the application of this technology. In this study, we targeted Cd contamination (using 15:1, 25:1, and 50:1 Ca

Microbiologically induced calcite precipitation (MICP) has shed new light on solving the problem of in situ stabilization of heavy metals (HMs) in sewage sludge before land disposal. In this study, we examined whether MICP treatment can be integrated into a sewage sludge anaerobic digestion-land application process. Our results showed that MICP treatment not only prevented the transfer of ionic-state Cd from the sludge to the supernatant (98.46 % immobilization efficiency) but also reduced the soluble exchangeable Pb and Cd fractions by up to 100 % and 48.54 % and increased the residual fractions by 22.54 % and 81.77 %, respectively. In addition, the analysis of the stability of HMs in MICP-treated sludge revealed maximum reductions of 100 % and 89.56 % for TCLP-extractable Pb and Cd, respectively. Three-dimensional fluorescence, scanning electron microscopy-energy-dispersive X-ray spectroscopy, X-ray diffraction, and Fourier-transform infrared spectroscopy analyses confirmed the excellent performance of the ureolytic bacteria Sporosarcina ureilytica ML-2 in the sludge system. High-throughput sequencing showed that the relative abundance of Sporosarcina sp. reached 53.18 % in MICP-treated sludge, and the urease metabolism functional genes unit increased by a maximum of 239.3 %. The MICP technology may be a feasible method for permanently stabilizing HMs in sewage sludge before land disposal.

Currently, the industrial application of bioelectrochemical systems (BESs) that are incubated with natural electrochemically active microbes (EABs) is limited due to inefficient extracellular electron transfer (EET) by natural EABs. Notably, recent studies have identified several novel living biomaterials comprising highly efficient electron transfer systems allowing unparalleled proficiency of energy conversion. Introduction of these biomaterials into BESs could fundamentally increase their utilization for a wide range of applications. This review provides a comprehensive assessment of recent advancements in the design of living biomaterials that can be exploited to enhance bioelectrocatalytic performance. Further, modular configurations of abiotic and biotic components promise a powerful enhancement through integration of nano-based artificial mediators and synthetic biology. Herein, recent advancements in BESs are synthesized and assessed, including heterojunctions between conductive nanomaterials and EABs, in-situ hybrid self-assembly of EABs and nano-sized semiconductors, cytoprotection in biohybrids, synthetic biological modifications of EABs and electroactive biofilms. Since living biomaterials comprise a broad range of disciplines, such as molecular biology, electrochemistry and material sciences, full integration of technological advances applied in an interdisciplinary framework will greatly enhance/advance the utility and novelty of BESs. Overall, emerging fundamental knowledge concerning living biomaterials provides a powerful opportunity to markedly boost EET efficiency and facilitate the industrial application of BESs to meet global sustainability challenges/goals.

ZnIn2S4, a novel two-dimensional visible light-responsive photocatalyst, has attracted much attention in the photocatalytic evolution of H2 under visible light irradiation due to its attractive intrinsic photoelectric properties and geometric configuration. However, ZnIn2S4 still has severe charge recombination, which results in moderate photocatalytic performance. Herein, we report the successful synthesis of 2D/2D ZnIn2S4/Ti3C2 nanocomposites by a facile one-step hydrothermal method. The efficiency of the nanocomposites in photocatalytic hydrogen evolution under visible light irradiation was also evaluated for different ratios of Ti3C2, and the optimal photocatalytic activity was achieved at 5% Ti3C2. Importantly, the activity was significantly higher than that of pure ZnIn2S4, ZnIn2S4/Pt, and ZnIn2S4/graphene. The enhanced photocatalytic activity is mainly due to the close interfacial contact between Ti3C2 and ZnIn2S4 nanosheets, which amplifies the transport of photogenerated electrons and enhances the separation of photogenerated carriers. This research describes a novel approach for the synthesis of 2D MXenes for photocatalytic hydrogen production and expands the utility of MXene composite materials in the fields of energy storage and conversion.

Purpose Colon cancer is one of the malignant tumors that threatens human health. miR-510 was demonstrated to play roles in the progression of various cancers; its dysregulation was speculated to be associated with the development of colon cancer. Methods One hundred and thirteen colon cancer patients participated in this research. With the help of RT-qPCR, the expression of miR-510 in collected tissues and cultured cells was analyzed. The association between miR-510 expression level and clinical features and prognosis of patients was evaluated. Moreover, the effects of miR-510 on cell proliferation, migration, and invasion of colon cancer were assessed by CCK8 and Transwell assay. Results miR-510 significantly upregulated in colon cancer tissues and cell lines relative to the adjacent normal tissues and colonic cells. The expression of miR-510 was significantly associated with the TNM stage and poor prognosis of patients, indicating miR-510 was involved in the disease progression and clinical prognosis of colon cancer. Additionally, the upregulation of miR-510 significantly promoted cell proliferation, migration, and invasion of colon cancer, while its knockdown significantly inhibited these cellular processes. SRCIN 1 was the direct target of miR-510 during its promoted effect on the development of colon cancer. Conclusion The upregulation of miR-510 acts as an independent prognostic indicator and a tumor promoter by targeting SRCIN 1 in colon cancer, which provides novel therapeutic strategies for colon cancer.

With the purpose of developing a novel approach of agricultural waste treatment and overcoming bottlenecks for upscaling solid-state fermentation processes, the type of aerated, continuously stirred solid-state bioreactors were used for the production of γ-PGA by Bacillus amyloliquefaciens JX-6. Using corn stalk and soybean meal, the most common agricultural waste in China, as solid substrates, the maximum production of γ-PGA was 116.88 ± 5.05 g/kg and 102.48 ± 3.30 g/kg in 50 L and 150 L bioreactors, respectively. Production of γ-PGA in 50 L bioreactor was higher than in 150 L bioreactor, demonstrating that a reduction in γ-PGA production occurred as the fermentation system enlarged. An analysis of the interactions among fermentation parameters (temperature, moisture, and pH), γ-PGA production, solid substrates and bacterial communities indicated that different bioreactor capacities caused changes in fermentation parameters and bacterial communities, which in turn affected substrate utilization and γ-PGA production. Overall, obtaining considerable amounts of γ-PGA under non-sterilized fermentation expressed that JX-6 has excellent abilities to adapt to these substrates and conditions. Bioconversion of agricultural waste into γ-PGA in scale-up fermentation was successfully conducted by creating a more stable and suitable fermentation environment in bioreactors.

Phenolic compounds are problematic byproducts generated from lignocellulose pretreatment. In this study, the feasibility degradation of syringic acid (SA), vanillic acid (VA), and 4-hydroxybenzoic acid (HBA) by Bio-Electro-Fenton (BEF) system with a novel Fe–Mn/graphite felt (Fe–Mn/GF) composite cathode were investigated. The nano-scale Fe–Mn multivalent composite catalyst with core shell structure distributed more evenly on GF surface to form a catalyst layer with higher oxygen reduction reaction performance. Accordingly, the maximum power density generated with Fe–Mn/GF cathode was 48.1% and 238.9% higher than Fe/GF and GF respectively, which further enhanced the in situ generation of H2O2 due to the superiority of nano-scale core shell structure and synergistic effect of Fe and Mn species. The degradation efficiency of the three phenolic compounds in the BEF system could reached 100% after optimization of influencing parameters. Furthermore, a possible SA degradation pathway by BEF process in the present system was proposed based on the detected intermediates. These results demonstrated an efficient approach for the degradation of phenolic compounds derived from lignocellulose hydrolysates.

A heterotrophic nitrifying aerobic denitrifying (HN-AD) strain HY-1 with excellent capacity, identified as Paracoccus denitrificans, was isolated from activated sludge. HY-1 was capable of removing NH

A novel photosensitized living biohybrid was fabricated by inward-to-outward assembly of amine-functionalized carbon dots (NCDs) and polydopamine (PDA) to Shewanella oneidensis MR-1 and applied for high-efficiency, microbial-photoreduction of Cr(VI). Within a 72h test period, biohybrids achieved a pronounced catalytic reduction capacity (100%) for 100mg/L Cr(VI) under visible illumination, greatly surpassing the poor capacity (only 2.5%) displayed by the wild strain under dark conditions. Modular configurations of NCDs and PDA afforded biohybrids with a large electron flux by harvesting extracellular photoelectrons generated from illuminated NCDs and increasing reducing equivalents released from an enlarged intracellular NADH/NAD+ pool. Further, increased production of intracellular c-type cytochromes and extracellular flavins resulting from the modular configuration enhanced the biohybrid electron transport ability. The enhancement of electron transport was also attributed to more conductive conduits at NCDs-PDA junction interfaces. Moreover, because NCDs are highly reductive, the enhanced Cr(VI) reduction was also attributed to direct reduction by the NCDs and the direct Cr(VI) reduction by sterile NCDs-assembled biohybrid was up to 20% in the dark. Overall, a highly efficient strategy for removal/transformation of Cr(VI) by using NCD-assembled photosensitized biohybrids was proposed in this work, which greatly exceeded the performance of Cr(VI)-remediation strategies based on conventional microbial technologies.

Background: Gemcitabine is considered a classical agent for the treatment of patients with pancreatic cancer. However, gemcitabine resistance is a common cause of treatment failure, leading to poor survival. Therapy to overcome gemcitabine resistance would benefit patients with pancreatic cancer. This study investigated the impact of aspirin (ASA) to gemcitabine resistance in the biological function of pancreatic cancer cells and the potential mechanism. Methods: The MTT assay, wound healing assay and annexin V-FITC/PI test was used to determine whether ASA could inhibit gemcitabine resistance in pancreatic cancer cells. Besides, the expression of Bcl-2, Bax, E-cadherin, Vimentin, p-PI3K, p-AKT and p-mTOR was detected by the Western blot. Statistically significant differences between groups were determined with the Student’s t-test. Results: The proliferation and migration of SW1990 and BxPC3 cells were significantly decreased while the apoptosis rate was increased in the combination of ASA and gemcitabine group (pppConclusion: Our research provided evidence ASA could help to inhibit gemcitabine resistance of pancreatic cancer cells, probably via inhibiting the PI3K/AKT/mTOR pathway and reversing EMT. Thus, combined use of ASA and gemcitabine is expected to be a potential therapeutic strategy for pancreatic cancer patients.

Adenosine, which is produced mainly by microbial fermentation, plays an important role in the therapy of cardiovascular disease and has been widely used as an antiarrhythmic agent. In this study, guanosine 5′-monophosphate (GMP) synthetase gene (guaA) was inactivated by gene-target manipulation to increase the metabolic flux from inosine 5′-monophosphate (IMP) to adenosine in B. subtilis A509. The resulted mutant M3-3 showed an increased adenosine production from 7.40 to 10.45 g/L, which was further enhanced to a maximum of 14.39 g/L by central composite design. As the synthesis of succinyladenosine monophosphate (sAMP) from IMP catalysed by adenylosuccinate synthetase (encoded by purA gene) is the rate-limiting step in adenosine synthesis, the up-regulated transcription level of purA was the potential underlying mechanism for the increased adenosine production. This work demonstrated a practical strategy for breeding B. subtilis strains for industrial nucleoside production.

Due to the promising applications, the demand to enhance poly-γ-glutamic acid (γ-PGA) production while decreasing the cost has increased in the past decade. Here, xylose/glucose mixture and corncob hydrolysate (CCH) was evaluated as alternatives for γ-PGA production by Bacillus amyloliquefaciens C1. Although both have been validated to support cell growth, glucose and xylose were not simutaneously consumed and exhibited a diauxic growth pattern due to carbon catabolite repression (CCR) in B. amyloliquefaciens C1, while the enhanced transcription of araE alleviated the xylose transport bottleneck across a cellular membrane. Additionally, the xyl operon (xylA and xylB), which was responsible for xylose metabolism, was strongly induced by xylose at the transcriptional level. When cultured in a mixed medium, xylR was sharply induced to 3.39-folds during the first 8-h while reduced to the base level similar to that in xylose medium. Finally, pre-treated CCH mainly contained a mixture of glucose and xylose was employed for γ-PGA fermentation, which obtained a final concentration of 6.56 ± 0.27 g/L. Although the glucose utilization rate (84.91 ± 1.81%) was lower than that with chemical substrates, the xylose utilization rate (43.41 ± 2.14%) and the sodium glutamate conversion rate (77.22%) of CCH were acceptable. Our study provided a promising approach for the green production of γ-PGA from lignocellulosic biomass and circumvent excessive non-food usage of glucose.

In the last few decades, many new synthesis techniques have been developed in order to obtain an effective visible-light responsive photocatalyst for hydrogen production by water splitting. Among these new approaches, the biotemplated synthesis method has aroused much attention because of its unique advantages in preparing materials with special morphology and structure. In this work, Hydrilla verticillata (L. f.) Royle was used as a biotemplate to synthesize a CdS photocatalyst. The as-synthesized sample had the microstructure of nano-scaled aggregate networks and its activity for photocatalytic hydrogen production was six times higher than that of CdS synthesized without a template in an Na2S-Na2SO3 sacrificial system. The use of Pt and PdS as cocatalysts further improved the hydrogen production rate to 14.86 mmol/g·h under visible-light (λ ≥ 420 nm) irradiation, so the hydrogen production can be directly observed by the naked eye. The results of characterization showed that the as-synthesized CdS photocatalyst has a high specific surface area and narrow band gap, which is favorable for light absorption and photocatalytic reaction. This work provides a new way to search for efficient visible-light catalysts and confirms the uniqueness of a biotemplated synthesis method in obtaining specially structured materials.

Constantly increased sewage sludge (SS) and fruit and vegetable wastes (FVW) are becoming the major organic solid wastes in human society. Thus, anaerobic digestion is employed as a low carbon energy strategy to reduce their environmental pollution risk. Anaerobic co-digestion system was developed based on the carbon to nitrogen ratio strategy. Results showed that the daily biogas production was higher in co-digester, and the volumetric biogas production rate (VBPR) significantly enhanced for 1.3 ∼ 3 folds, and the highest VBPR was 2.04 L/L • day with optimal OLR of 2.083 Kg L

In order to further improve the photocatalytic performance of the SiO2/TiO2 composite under visible light irradiation, curcumin-doped SiO2/TiO2 nanocomposites were synthesized via directly incorporating it into the structure of SiO2/TiO2 during the synthesis using an inexpensive and readily available natural pigment (curcumin) as doping agent. The physicochemical properties of SiO2/TiO2 nanocomposites were characterized in detail by X-ray diffraction, transmission electron microscopy, Fourier transform-infrared spectroscopy, N2 adsorption&ndash, desorption isotherms, X-ray photoelectron spectroscopy, and UV-vis diffuse reflectance spectroscopy. The results indicate that all SiO2/TiO2 nanocomposites exhibited an anatase phase with a typical mesoporous structure. It was found that the dope of curcumin in the SiO2/TiO2 composite could decrease the crystal size, slightly improve the specific surface areas, significantly enhance the visible light absorption, and effectively narrow the band gap energy from 3.04 to 10(eV). Compared with bare SiO2/TiO2, the curcumin-doped SiO2/TiO2 resulted in enhanced photocatalytic reduction activity for Cr(VI) under visible light irradiation, and the CTS (12) sample with the appropriate content of curcumin of 12 wt % shows the photocatalytic yield reaching 100% within 2.5 hours, which is larger than CT (12) without silica. This could be attributed to the curcumin doping and the synergetic effects of SiO2 and TiO2 in SiO2/TiO2 nanocomposites.

Background: Microbial chitinases have attracted a lot of attention because of their great potential in many applications. Metagenome-based approach obtains the target genes from the environment directly without culturing the microbes and is becoming a powerful tool to discover the novel chitinases.Results: Gene P1724 was found in a chitin-enriched microbial community from a wetland on the Qinghai-Tibetan plateau using the metagenomic approach. The translated protein sequence of P1724 was predicted to have two GH18 catalytic domains and showed very low similarities with any known and hypothetical chitinases. The gene sequence of P1724 , its N-terminal GH18 domain ( P1724nGH18 ), or C-terminal GH18 domain ( P1724cGH18 ) was cloned and expressed in Escherichia coli BL21 (DE3). Using colloid chitin as substrate, these purified recombinant chitinases showed maximum hydrolytic activities at 40 °C, pH 5.0-6.0 and 0-0.5 M NaCl, and were cold adaptive since they were still active at 4 °C; the activities of three chitinases were decreased with the presence of Cu 2+ and EDTA, but increased with Ba 2+ and Ca 3+ ; all three chitinases showed both chitotiosidase and endochitinase activities, and could hydrolyze chitosan as well. Other than these common characteristics, P1724 and P1724nGH18 shared more similarity in temperature and pH stabilities, NaCl tolerance and substrate affinity, suggesting the N-terminal GH18 domain contributed more than the C-terminal GH18 did in biochemical characteristics of P1724. k cat / K m value (catalytic efficiency) of P1724 was significantly higher than the sum values of P1724nGH18 and P1724cGH18, which indicated that two GH18 domains of P1724 worked cooperatively in degrading chitin.Conclusion: Compared to most microbial chitinases that contain only one catalytic domain, P1724 contains two and was firstly discovered by the metagenomic approach. P1724, its N-terminal and C-terminal catalytic domains were heterologously expressed and characterized. These three recombinant chitinases are phylogenetically distant to any chitinases studied so far, have unique hydrolytic mode, high catalytic efficiency and so new promising candidates for chitinases in applications. In addition, this study broadens the knowledge of unknown chitinases in nature and shows a natural strategy for enzyme engineering by adding other catalytic domain(s).

Background: Microbial chitinases have attracted a lot of attention because of their great potential in many applications. Metagenome-based approach obtains the target genes from the environment directly without culturing the microbes and is becoming a powerful tool to discover the novel chitinases. Results: A metagenomic approach was used to discover the chitinases from a wetland on the Qinghai-Tibetan plateau. Gene P1724 was found and predicted to have two GH18 catalytic domains. Gene sequence containing P1724 , only its N-terminal GH18 domain ( P1724nGH18 ) or only C-terminal GH18 domain ( P1724cGH18 ) were cloned and expressed in Escherichia coli BL21 (DE3). These purified recombinant chitinases showed maximum hydrolytic activities at 40 °C, pH 5.0-6.0 and 0-0.5 M NaCl, and were cold adaptive since they were still active at 4 °C. The activities of three chitinases were decreased with the presence of Cu 2+ and EDTA, but increased with Ba 2+ and Ca 3+ . All three chitinases showed both chitotiosidase and endochitinase activities, and produced predominantly N, N΄-Diacetylchitobiose from colloid chitin. Other than these common characteristics, P1724 and P1724nGH18 shared more similarity in temperature and pH stabilities, NaCl tolerance and substrate affinity, suggesting the N-terminal GH18 domain contributed more than the C-terminal GH18 did in biochemical characteristics of P1724. k cat / K m value (catalytic efficiency) of P1724 was significantly higher than the sum values of P1724nGH18 and P1724cGH18’s, which indicated that two GH18 domains of P1724 works synergistically in degrading chitin. Conclusion: Compared to the most of microbial chitinases containing only one catalytic domain, chitinases P1724 with two GH18 catalytic domains was discovered firstly by the metagenomic approach. P1724 is a novel chitinase with unique amino acid sequences and hydrolytic mode, and could be used in cold environments or industries.

Climate change and water table drawdown impact the community structure and diversity of peatland soil prokaryotes. Nonetheless, how soil prokaryotes of different water tables respond to climate change remains largely unknown. This study used 16S rRNA gene sequencing to evaluate the variation in soil prokaryotes under scenarios of warming, rainfall reduction, and their combination in different water table peatlands on the Zoige Plateau in China. Stimulated climate change affected some of the diversity indexes and relative abundances of soil prokaryotes in three water table peatlands. Additionally, those from the dry-rewetting event peatland had the most dominant phyla (genera) that showed significant changes in a relative abundance due to the simulated climate change treatments. Regarding functional microbial groups of carbon and nitrogen cycling, simulated climate change did not affect the abundances of the Euryarchaeota, Proteobacteria, Verrucomicrobia, and Methanobacterium in three water table peatlands, except NC10 and Nitrospirae. Redundancy analysis showed that the prokaryotic community variation was primary impacted by site properties of the different water table peatlands rather than the simulated climate change treatments. Moreover, the water table, total carbon, total nitrogen, and soil pH were the primary factors for the overall variation in the soil prokaryotic structure. This study provides a theoretical guidance for management strategies in the Zoige peatland, under climate change scenarios. More attention should be given to the interactive effects of peatland water table drawdown and simulated climate changes for better restorative efforts in water table drawdown, rather than simply adapting to climate change.

In this study, a double E strategy (enzymes and enhancer) characterized by high efficiency for enhancing sewage sludge anaerobic digestion (AD) is proposed. This strategy combines addition of trace elements (TEs) enhancer and enzyme pretreatment, inducing a synergistic effect on AD, and it is more effective and economical compared with TEs addition or enzyme pretreatment in isolation. When adding 400 U/g cocktail enzymes and 1.24% trance elements enhancers, the cumulative methane production and the maximum daily methane increased yield by 45.29% and 84.7%, respectively. According to microbial community analysis, the double E strategy significantly motivate the growth of acetogens and protein fermenting bacterium. The relative abundance of Fermentimonas and Lutispora increased by 6.15% and 5.4%, respectively. Archaeal community analysis and changes in the mcrA gene abundance demonstrate enrichment of hydrogenotrophic methanogens, with the methanogens exhibiting high vitalities and stress resistance. The double E strategy could be a promising way to improve industrial sewage sludge AD efficiency.

Nowadays, Metaverse is very popular around the world. People read a lot of news reports about the metaverse every day. In many people’s minds, the metaverse may be the future of humanity. Most investors prefer to invest companies which have some relationship with Metaverse products. However, how metaverse would fully integrate into our lives is still unclear, and there are numerous proposed solutions in the market. In order to evaluate the feasibility of metaverse applications, we will focus on what Metaverse is, the existing Semi-Metaverse attempt, the existing Metaverse application and the Metaverse university that the CUHKSZ’s students made in this paper. Besides, we will also talk about the potential risks that the Metaverse may bring. At the end, we illustrate what Metaverse need to prepare and improve in the future. If Metaverse can be realized in the future, it will bring infinite convenience to human life. However, it is still very difficult to fully realize Metaverse depending on today’s science and technology.

The impacts of different S/N molar ratios and fillers (polyurethane foam, multi-surface hollow spheres, and pall rings) on the process of simultaneous desulfurization and denitrification (SDD) were studied by using anaerobic biotrickling filer (BTF). Furthermore, the SDD mechanism was described by dividing the SDD process into three stages based on pH changes: (I) increase (II) decrease and (III) stable state. The maximum desulfurization and denitrification efficiency (13.5 g-S m−3 h−1 and 3.7 g-N m−3 h−1, respectively) was achieved by applying polyurethane foam as filler. When S2− and S0 coexist as electron donors in the SDD system, the functional microbes degrade S2− preferentially. The S/N molar ratios of the influent were higher, and the relative content of sulfate in the products was less. Considering the efficiency and economic benefits, polyurethane foam is suggested as fillers for practical implementations of SDD systems. The S/N molar ratios should be controlled in a 5/3 to 5/2 range and HS−/S2− concentration should be

Microbial oxidation by bacteria with the potential to oxidize C1 compounds (methanotrophs) is the only biological sink for atmospheric methane (CH4). Aerobic methanotrophs are particularly active in forest soils, but the role of aerobic methanotrophs in native forest soils in China remains poorly understood. The pmoA gene, encoding the key enzyme methane monooxygenase (particulate MMO), is widely used to identify methanotrophic communities. We collected soils from different vegetation types in one subtropical and one temperate forest in China. Potential CH4 oxidation rates and methanotroph communities were assessed via laboratory incubation and pmoA-based phylogenetic analysis, respectively. Across all sampling sites, we observed distinct variations in methanotroph community composition and CH4 oxidation rates. In all soils, CH4 oxidation rates increased with increasing CH4 concentration. Elevated temperature resulted in an increase in the CH4 oxidation rates in coniferous forests, while a decrease in deciduous forests. Restriction fragment length polymorphism analyses indicated that methantrophic community varied in different vegetation types. The methanotroph communities were dominated by type II methanotrophs (including soil cluster alpha (SCα), Methylocystis, and USCα) and type I methanotrophs (including USCγ and Methylobacter) in deciduous and coniferous forests, respectively. It is suggested that intrinsic differences in CH4 oxidation rate responses to temperature between coniferous and deciduous soils are likely due to different methanotroph community structures. Taken together, the direction of CH4 feedback responses to disturbance was site specific.

The purpose of this study was to investigate the anaerobic digestion (AD) of rice straw at different temperatures in a 300 m3 bioreactor. The results showed that the biogas yield was 401.9 m3/ton (...

The aim of this work was to study the acetate separation from fresh vinegar residue (FVR) to avoid inhibition of methanogenesis and hydrothermal treatment on washed vinegar residue (WVR) to enhance methane production. The optimal liquid-solid ratio was 10:1mL/g for the washing of FVR. The methane yields of the FVR, WVR, and washed leachate (WL) were 273L/kgVS, 199L/kgVS, and 306.9L/kgCOD, respectively. The optimal hydrothermal temperature was 160°C for WVR, with maximum methane yield of 258.38L/kgVS. Hydrothermal pretreatment destroyed the structure of lignocellulose and improved the hydrolysis of hemicellulose. Compared with thermophilic digestion of FVR, thermophilic digestion of 160°C treated FVR, and thermophilic digestion of WVR with mesophilic digestion of WL, the thermophilic digestion of 160°C treated WVR with mesophilic digestion of WL obtained the maximum total methane yield of 102.5L/kgFVR.

Metagenomic sequencing, basing on whole genomic analysis, was carried out to explain the taxonomic and functional patterns of microbial communities in co-digestion and mono-digestions with corn straw and pig manure. Bacteroides graminisolvens and Clostridium stercorarium, the dominant species for corn straw degradation, and Proteiniphilum acetatigenes, emphasizing on protein decomposition, performed the optimum abundance during the co-digestion to improve efficiency of substrate decomposition. Methanosaeta concilii was the richest species during the process of bio-methane production, whose quantity and status in co-digestion were better than in mono-digestion. Analysis of functional patterns indicated that the carbohydrate-active enzymes in co-digestion were sustained abundant resulting short lag time, and the abundance of enzymes involving in methanogenesis were extremely high in co-digestion indicating the active methane metabolism. An adequate understanding of taxonomic and functional patterns further revealed the mechanism of rapid startup and superb methane production in co-digestion.

As a new bioremediation technology for toxic metals, microbiologically induced calcite precipitation (MICP) is gradually becoming a research focus. This study investigated the application of MICP to mineralize toxic metals (lead and cadmium) in landfill leachate for the first time. In the experiment of remediating synthetic landfill leachate (SLL) contaminated by Pb2+, 100% of the 20 mg/L Pb2+ was removed when the maximum urease activity was only 20.96 U/ml. Scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS) and laser particle size characterizations of the precipitates indicate the formation of agglomerated square particles, 76.9% of which had sizes that ranged from 33.93 to 57.06 μm. Fourier transform infrared spectroscopic and X-ray diffraction analyses confirmed that the precipitates consisted predominantly of calcite crystals, and the unit cell lattice constants of the precipitates (a = b = 4.984 A, c = 17.171 A) matched those of calcite, while lead was fixed as hydrocerussite. In addition, the Pb-MICP precipitates were stable under continuous acid degradation (pH = 5.5), and only 1.76% of the lead was released after 15 days. In the verification test of toxic metals remediation in a real landfill leachate (RLL), all of the Pb2+ and Cd2+ (initial concentrations: Pb2+ = 25 mg/L; Cd2+ = 5.6205 mg/L) was mineralized simultaneously, which further confirmed the feasibility of MICP for toxic metal remediation in landfill leachate. However, optimizing the urea dosage and combining the ammonium recovery are necessary strategies required for improving the economic and environmental benefits of the MICP process.

In this study, to efficiently remove malodorous gas and reduce secondary pollution under mixotrophic conditions, pine bark, coal cinder, straw and mobile bed biofilm reactor (MBBR) fillers were used as packing materials in a biological trickling filter (BTF) to simultaneously treat high-concentration H2S and NH3. The results showed that the removal rate of BTF-A filled with pine bark was the highest, which was 86.31% and 94.06% under the H2S and NH3 loading rates of 53.59 g/m³·h while the empty bed residence time (EBRT) was 40.5 s. The theoretical maximum load was obtained by fitting the kinetic curve, and the value were 90.09 g H2S m-³·h−1 and 172.41 g NH3 m-³·h−1. Meanwhile, after treating with 720 ppm of NH3, the average concentration of NO3- in the BTF circulating fluid was only 127.58 mg/L, indicating the better performance of secondary pollutants control. Microbiological analysis showed that Dokdonella, Micropruina, Candidatus_Alysiosphaera, Nakamurella and Thiobacillus possessed high abundance at the genus level, and their entire percentage in four BTF reactors were 62.87%, 46.32%, 47.98%, and 57.35% respectively. It is worthwhile that the genera Comamonas and Trichococcus with heterotrophic nitrification and aerobic denitrification capabilities and proportion of 3.66%, 1.45%, 5.43%, and 3.23% were observed in four reactors.

Microbial fuel cell (MFC) is a promising device for energy generation and organic waste treatment simultaneously by electrochemically active bacteria (EAB). In this study, an integrated aerobic-anaerobic strategy was developed to improve the performance of P. aeruginosa-inoculated MFC. With an aerobic start-up and following an anaerobic discharge process, the current density of MFC reached a maximum of 99.80µA/cm2, which was 91.6% higher than the MFC with conventional constant-anaerobic operation. Cyclic voltammetry and HPLC analysis showed that aerobic start-up significantly increased electron shuttle (pyocyanin) production (76% higher than the constant-anaerobic MFC). Additionally, enhanced anode biofilm formation was also observed in the integrated aerobic-anaerobic MFC. The increased pyocyanin production and biofilm formation promoted extracellular electron transfer from EAB to the anode and were the underlying mechanism for the MFC performance enhancement. This work demonstrated the integrated aerobic-anaerobic strategy would be a practical strategy to enhance the electricity generation of MFC.

This study investigated methane productions and the microbial communities in the batch anaerobic digestion process with the mono-digestion of corn stalk (CS) and pig manure (PM), and the co-digestion of them. Co-digestion showed the best methane performance, the cumulative methane yield, 256.57 mL·gVS −1 ; methane production potential, 281.55 mL·gVS −1 ; maximum methane production rate, 10.17 mL·d −1 ·gVS −1 ; and lag phase, 4.24 d. Moreover, co-digestion achieved a more suitable microenvironment including pH, FA and FVFA compared to mono-digestions. Results of high-throughput sequencing indicated that in co-digestion the dynamic changes of relative abundances of phyla and predominant genera were very small and community structure presented a stable status. Acetoclastic pathway was the main biochemical pathway of methanogenesis in co-digestion and mono-digestion of PM, and the growth rate of Methanosaeta in co-digestion was higher. So suitable microenvironment in co-digestion resulted in high growth rate of methanogens and stable microbial community, and leaded to the high methane production.

The intensive use of triphenyltin chloride (TPTC) has caused serious environmental pollution. In this study, an effective method for TPTC degradation was proposed based on the Bio-Electron-Fenton process in microbial fuel cells (MFCs). The maximum voltage of the MFC with graphite felt as electrode was 278.47% higher than that of carbon cloth. The electricity generated by MFC can be used for in situ generation of H2O2 to a maximum of 135.96μmolL-1 at the Fe@Fe2O3(*)/graphite felt composite cathode, which further reacted with leached Fe2+ to produce hydroxyl radicals. While 100μmolL-1 TPTC was added to the cathodic chamber, the degradation efficiency of TPTC reached 78.32±2.07%, with a rate of 0.775±0.021μmolL-1h-1. This Bio-Electron-Fenton driving TPTC degradation might involve in SnC bonds breaking and the main process is probably a stepwise dephenylation until the formation of inorganic tin and CO2. This study provides an energy saving and efficient approach for TPTC degradation.

One-step hydroxylation of C-H (sp 2 ) of aromatic ring synchronized with the oxidation of C-H (sp 3 ) of side-chain of p -xylene to 2,5-dihydroxyterephathalic acid was performed using M-MCM-41 (M = Fe, Fe/Cu, Cu) as the catalysts. Cu-MCM-41 (Cu:Si = 1:100) catalyst exhibited good selectivity (73.0%) of 2,5-dihydroxyterephathalic acid and conversion (21.7%) of p -xylene using acetic acid and acetonitrile (V:V = 3:7) as the solvents at 80 °C for 5 h. The possible mechanism of the oxidation of p -xylene to 2,5-dihydroxyterephathalic acid was proposed and would guide us to design high performance catalyst for sp 2 and sp 3 C-H oxidation. This procedure is also expected to be an alternative method to Kolbe-Schmitt Process for the synthesis of o -hydrobenzoic acids and their derivatives.

Graphene-based composite materials are versatile but not easily procurable. Cyanobacterial cells, an outgrowth of eutrophic freshwater lake, were simultaneously employed as a template for the growth of ZnO nanoparticles and as a biomass carbon source for graphene sheets, resulting in chlorophyll-containing graphene-wrapped ZnO nanospheres.

Taking earthquake and life pictures with more ecological validity as experimental materials and using ERP technology to explore whether the important personality trait of introversion and extroversion can regulate empathy for sadness. The ERP results showed early differentiation between earthquake and life pictures over the frontal area at 180 ms after sensory stimuli. A long-latency empathic response was observed after 280 ms over the central-parietal regions. Introversion and extroversion individuals showed significant differences in the early stages. The ERPs of introversion individual was more negative, however, introversion and extroversion didn't show modulation on empathy for sadness. The correlation between subjective reports and neural activity showed different characteristics between introversion and extroversion individuals.

N-doped TiO2 with oxygen vacancies exhibits many advantages for photocatalysis, such as enhanced visible light absorbency, inhibition of the photogenerated charge carrier recombination, etc. However, preparation of N-doped TiO2 with oxygen vacancies under mild conditions is still a challenge. Herein, N-doped TiO2 nanospheres with tetrahedral Ti4+ sites were synthesized by using dodecylamine as template and assisted by l-alanine acids. The obtained samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV–Vis diffuse reflectance spectra (UV–Vis DRS). It was found that the dodecylamine as a neutral surfactant controlled the structure of TiO2 spherical, while l-alanine acids provided a nitrogen source. The existence of tetrahedral Ti4+ sites in N-doped TiO2 was also confirmed. The N-doped TiO2 sample with tetrahedral Ti4+ sites exhibited significantly improved photocatalytic performance for degradation of methylene blue solution under UV light or visible light irradiation. A combined time-resolved infrared (IR) spectroscopy study reveals that the enhanced photocatalytic performance could be attributed to a large amount of photogenerated charge carriers and efficient charge separation. It is demonstrated that the shallow donor state produced by oxygen vacancies of tetrahedral Ti4+ sites can effectively promote separation of charge carriers besides capturing electrons.

In this study, a core-shell Fe@Co nanoparticles uniformly modified graphite felt (Fe@Co/GF) was fabricated as the cathode by one-pot self-assembly strategy for the degradation of vanillic acid (VA), syringic acid (SA), and 4-hydroxybenzoic acid (HBA) in the Bio-Electro-Fenton (BEF) system. The Fe@Co/GF cathode showed dual advantages with excellent electrochemical performance and catalytic reactivity not only due to the high electron transfer efficiency but also the synergistic redox cycles between Fe and Co species, both of which significantly enhanced the in situ generation of H2O2 and hydroxyl radicals ( OH) to 152.40 μmol/L and 138.48 μmol/L, respectively. In this case, the degradation rates of VA, SA, and HBA reached 100, 94.32, and 100%, respectively, within 22 h. Representatively, VA was degraded and ultimately mineralized via demethylation, decarboxylation and ring-opening reactions. This work provided a promising approach for eliminating typical recalcitrant organic pollutants generated by the pre-treatment of lignocellulose resources.

Nitrogen loss is the main problem in compost and controlling it is the key to the recovery and utilization of composted materials. This study systematically investigated the effect of nitrogen retaining microbial agent (NRMA) on nitrogen retention and the promotion of decay during manure composting and tested its effect on nitrogen conversion and bacterial community structure. During composting, various parameters were dynamically evaluated, including nitrogen loss and transformation, compost maturity and nutrient, microorganism population and bacteria community variation. Results showed that the inoculation of NRMA significantly reduced ammonia loss by 58.8% with 15 days shorter compost cycle. At the end of the composting, the total nitrogen (TN) and nitrate content of the experimental group were 23.3 g kg−1 and 4.5 g kg−1, 22.6% (p

With polyhedral spheres as the packing, a semi-pilot biological trickling filter reactor (BTF) inoculated by domesticated activated sludge is used to remove Hydrogen Sulphide (H2S) and Ammonia (NH3). The removal rate of H2S and NH3 by BTF was as high as 98.25% and 88.55%, and the maximum removal load was 84.57 g H2S m−3h−1 and 38.77 g NH3 m−3h−1 during the 61-day process. The inlet gas concentration ranges from 0 to 500 ppm, and the empty bed residence time (EBRT) is 31.8 s. When the EBRT reduced from 31.8s to 25.4s, the removal rate of H2S and NH3 decreased significantly, which was 67.21% and 81.36%, respectively. The results showed that EBRT significantly affected the removal rate of H2S and NH3. Microbial analysis indicated that Dokdonella, Ferruginibacter, Nitrosomonas, and Thiobacillus had high abundance at the genus level, showing that these genera play an important role in the degradation of H2S and NH3. When the optimized parameters applied to the on-site biogas residue compost, the removal rate of H2S and NH3 by BTF can reach 91.34%, which provides a feasible process for the deodorization project with compost.

Minerals are ubiquitous in the natural environment and have close contact with microorganisms. In various scenarios, microorganisms that harbor extracellular electron transfer (EET) capabilities have evolved a series of beneficial strategies through the mutual exchange of electrons with extracellular minerals to enhance survival and metabolism. These electron exchange interactions are highly relevant to the cycling of elements in the epigeosphere and have a profound significance in bioelectrochemical engineering applications. In this review, we summarize recent advances related to the effects of different minerals that facilitate the EET process and discuss the underlying mechanisms and outlooks for future applications. The promotional effects of minerals arise from their redox-active ability, electrical conductivity and photocatalytic capability. In mineral-promoted EET processes, various responses have concurrently arisen in microorganisms, such as stretching of electrically conductive pili (e-pili), upregulated expression of outer-membrane cytochromes (Cyts) and production of specific enzymes, and secretion of extracellular polymeric substances (EPSs). This review synthesizes the understanding of electron exchange mechanisms between microorganisms and minerals and highlights potential applications in development of renewable energy production and pollutant remediation, which are topics of particular significance to future exploitation of biotechnology.

In order to develop a time-saving method for determination of ultimate methane production, obtain the hydrolysis kinetic constant, and identify a determination method for the nonbiodegradable organic fraction of substrate (VSNB) of green and air-dried corn stover, the kinetics of methane production and hydrolysis were studied using batch tests. The results showed that the conventional first-order hydrolysis kinetic model was not suitable for describing the entire hydrolysis process of corn stover, because there were two first-order decay periods for hydrolysis of corn stover. The hydrolysis kinetic constants kH,1 and kH,2 of the first and second periods were 0.1701 and 0.0415 1/d for green stover and 0.1052 and 0.0360 1/d for air-dried stover. The value of VSNB could be obtained by the graphical method rather than by the hydrolysis kinetic model. The obtained VSNB contents were 12.9% and 24.7% of VS (volatile solid) for green and air-dried stover, respectively. The ultimate methane production and corresponding digestion time could be understood through the methane production kinetic model by digestion experiments within a short time. The ultimate methane productions were 347.1 and 319.4 mL/g based on VS and the corresponding digestion times were 69.2 and 182.3 days for green and air-dried stover, respectively.

Micro-aerobic and anaerobic fermentative hydrogen productions were carried out in bottle tests (150 mL) and scale-up bioreactors (10 L) using corn straw as a substrate. Hydrogen yield of 41.6 mL/g (volatile solid, VS) obtained from scale-up experiment with optimal oxygen addition of 0.28 mL/(g (total solid, TS)·day) was higher than that of 28.9 mL/g VS without additional oxygen. Oxidation reduction potential was−300∼−150 mV for micro-aerobic fermentation, where it was−560∼−360 mV for anaerobic fermentation. The micro-aerobic condition had strong buffering ability and could tolerate a greater accumulation of volatile fatty acid. Both micro-aerobic and anaerobic hydrogen production were butyric acid-type fermentation. Microbial community analysis indicated the presence of Citrobacter sp. and Escherichia sp., which were unique to micro-aerobic system, as well as classical Enterococcus, Bacteroides, Peptoclostridium, Clostridium genera that existed in both micro-aerobic and anaerobic fermentation.