Enhanced biodegradation of thiamethoxam with a novel polyvinyl alcohol (PVA)/sodium alginate (SA)/biochar immobilized Chryseobacterium sp H5

Characterization of a novel 1,2-dichloroethane degrader Ancylobacter sp. J3 and use of its immobilized cells in the treatment of polluted groundwater

A novel 1,2-dichloroethane (1,2-DCA) degrading bacteria strain J3 was isolated from 1,2-DCA contaminated groundwater and identified as Ancylobacter sp. The strain J3 was associated with self-flocculation during the growth process, and the degradation pathway study showed that the bacteria could completely mineralize 1,2-DCA. The microorganism was immobilized and the optimum preparation conditions were obtained by orthogonal experiment: 6 % polyvinyl alcohol, 2 % sodium alginate, 1 % biochar, and 2 % CaCl2, and the immobilized cells were named J3C. The degradation rates of J3C at low pH, temperature, and high concentration NaCl were higher than that of free J3. The fitting results of the pseudo-first-order degradation kinetics model showed that for above 200 mg/L 1,2-DCA, the degradation rate of J3C was higher than that of free J3. The adsorption process of the sterile J3C aligns with the pseudo-first-order kinetic model and the intraparticle diffusion model. The internal mass transfer kinetics analysis revealed that the beads with biochar and a small diameter (0.34 cm) were more conducive to mass transfer. Finally, remediation of real polluted groundwater by J3C shows that for groundwater with a pH value of about 7, 1,2-DCA concentrations of about 100, 200 mg/L, 1,2-DCA can be completely degraded by J3C, while for groundwater with a pH value of 12, 250 mg/L 1,2-DCA, the degradation rate was 83.15 % by J3C, 66.91 % higher than that of free J3. The changes in microbial communities in groundwater showed that J3C disturbed the groundwater microbial little for the immobilized cells in J3C originated from the groundwater.

Nitrate-induced microbial metabolic activation and community composition optimization enhance the anaerobic biodegradation of thiamethoxam

This study investigated the impact of nitrate on the biodegradation potential of thiamethoxam (THM) in aquatic environments. It was found that the introduction of different nitrate concentrations significantly improved the anaerobic biodegradation efficiency of THM. Notably, the degradation rate of THM enhanced remarkably as nitrate concentration increased. As the nitrate concentration was elevated to 200 mg·L-1, the removal rate of THM significantly increased to 85.92%, which was 7.45 times higher than that of the control system. Analysis of results from Tafel, AC impedance (EIS), electron transport activity (ETSA), and nicotinamide adenine dinucleotide (NADH) revealed that the addition of nitrate enhanced the electrochemical activity of the system and the efficiency of electron transfer. Furthermore, nitrate promotes the secretion of extracellular polymers and activates the activity of related enzymes, such as nitrate reductase (NAR), nitrite reductase (NIR), and catalase (CAT). Macro-transcriptome analyses showed that nitrate addition changed the structure of the microbial community, regulated the expression of relevant functional genes, and increased microbial metabolic activity, thereby effectively accelerating the biodegradation of THM. This study provides new insights into the relationship between nitrate and the biological anaerobic degradation of THM.

Immobilization of Acinetobacter sp. A-1 and Applicability in Removal of Difenoconazole from Water-Sediment Systems

Difenoconazole, as a systemic triazole fungicide, is a broad-spectrum, highly effective agent that has been widely used for controlling fungal diseases in 46 different crops (or crop categories), including rice, wheat, and corn. Due to the improper use of difenoconazole, concerns about its environmental residues and toxicity to non-target organisms have drawn significant attention from researchers. In response to this issue, this study aimed to isolate microbial strains capable of degrading difenoconazole from the environment. A novel difenoconazole-degrading strain, Acinetobacter sp. A-1, was screened and identified, demonstrating the ability to degrade 62.43% of 50 mg/L difenoconazole within seven days. Further optimization of the degradation conditions was conducted using single-factor experiments and response surface methodology experiments. The results showed that the optimal degradation conditions for strain A-1 were a difenoconazole concentration of 55.71 mg/L, a pH of 6.94, and an inoculation volume of 1.97%, achieving a degradation rate of 79.30%. Finally, strain A-1 was immobilized using sodium alginate, and its stability and bioremediation efficiency were evaluated. The results indicated that the immobilized strain A-1 exhibited high stability and significantly reduced the half-life of difenoconazole in the water-sediment contamination system. In the sterilized water-sediment system, the degradation rate of difenoconazole by the immobilized strain A-1 reached 65.26%. Overall, this study suggests that Acinetobacter sp. A-1 is a promising candidate for difenoconazole degradation, and immobilization technology can effectively enhance its removal efficiency in water-sediment systems.

In situ remediation of eutrophic Wolong Lake sediments using novel PVA-SA-biochar and PVA-SA-zeolite embedded immobilized indigenous microorganisms: a pilot study

Sediment restoration has become a key link in river and lake pollution control. This present study investigated the selection of dominant microbial bacteria, the selection and optimization of microbial immobilized carrier materials, and the effect of embedded immobilized microbial in situ remediation of bottom sediments based on the actual restoration pilot project of eutrophic Wolong Lake. The composite of denitrifying and photosynthetic bacteria at a ratio of 1 : 2 showed the best performance with COD, TN, and TP removal efficiencies of 74.86%, 65.2%, and 67.5%, respectively. Denitrifying bacteria to photosynthetic bacteria optimal composite bacterial solutions with polyvinyl alcohol-sodium alginate (PVA-SA), PVA-SA-zeolite and PVA-SA-biochar carriers were selected, and the effects of different carriers were analyzed and compared in terms of multiple characteristics. PVA-SA-biochar carriers showed the best ammonia-nitrogen transfer performance, mass transfer coefficient (0.681 × 10-9 m2 s-1), specific surface area (76.3 m2 MB g-1) and performed best in mechanical strength and chemical stability. The effects of biochar, PVA and SA contents on COD removal (Y) were analyzed using the 3D-response surface methodology. Biodegradation capacity (G-value) increased from 0.68 × 10-3 kg (kg h)-1 at the beginning of the test to 2.32 × 10-3 kg (kg h)-1 after 80 days of the remediation test with a growth rate of 258.82%. The water quality index has significantly improved, indicating a good restoration effect. Alpha diversity analysis showed that the Shannon and Simpson indexes increased and decreased. The relative abundance of Bacteroidota, Proteobacteria, Planctomycetota and Chloroflexi, closely related to the denitrification, decarbonization and phosphorus removal, increased while Chloroflexi decreased compared with before restoration. Embedded immobilized microbial technology significantly enhances the quality of sediment mud and the overlying water. In the long term, this approach does not release toxic substances into water bodies, thus fostering biodiversity and promoting ecological restoration. It represents a novel restoration strategy that contributes positively to environmental sustainability.

Effects of compound immobilized bacteria on remediation and bacterial community of PAHs-contaminated soil

Immobilized microorganism technology is expected to enhance microbial activity and stability and is considered an effective technique for removing soil polycyclic aromatic hydrocarbons (PAHs). However, there are limited high-efficiency and stable bacterial preparations available. In this study, alkali-modified biochar (Na@CBC700) was used as the adsorption carrier, sodium alginate (SA) and polyvinyl alcohol (PVA) as embedding agents, and CaCl2 as the cross-linking agent to prepare immobilized Acinetobacter (CoIMB) through a composite immobilization method. The CoIMB preparation was optimized using response surface methodology and applied to PAH-contaminated soil remediation. Results indicated that CoIMB exhibited improved mechanical strength and microbial activity, achieving degradation rates of 2-5 rings PAHs up to 82.41 %, averaging 1.5 times higher than CK. High dose CoIMB treatment enhanced soil microbial community diversity, enriching Acinetobacter, and increased the abundance of functional genes related to fatty acid metabolism and energy metabolism (K00249, K01897, K00059). This composite immobilized bacterial particle provides a novel, broad-spectrum, and cost-effective solution for remediating organic pollutants in soil environments.

Natural Products Produced by the Species of Bacillus cereus Group: Recent Updates

Bacillus cereus group produces diverse antimicrobial compounds through different metabolic pathways, including amino acid-based compounds, sugar derivatives, volatile and miscellaneous compounds. These antimicrobial compounds exhibit antibacterial and antifungal activities against various plant pathogens, promoting plant growth and enhancing tolerance to abiotic stresses. They also exhibit nematicidal activities against plant nematodes and antagonistic effects against pathogens in aquatic animals, promoting growth and inducing immune responses. Moreover, B. cereus group bacteria play a significant role in bioremediation by breaking down or neutralizing environmental pollutants, such as plastics, petroleum products, heavy metals, and insecticides. They produce enzymes like laccases, lipases, proteases, and various oxidases, contributing to the degradation of these pollutants. In the food industry, they can cause food poisoning due to their production of enterotoxins. However, they are also utilized in various industrial applications, such as producing environmentally friendly bio-based materials, biofertilizers, and nanoparticles. Notably, B. cereus transforms selenite into selenium nanoparticles, which have health benefits, including cancer prevention. In summary, B. cereus group bacteria have diverse applications in agriculture, bioremediation, industry, and medicine, contributing to sustainable and eco-friendly solutions across multiple fields. In this review, we have revised B. cereus group and the characteristics of every species; we have also highlighted the more important compounds secreted by the species of B. cereus group and the applications of these compounds. The aim is to explain the available secondary metabolites to classify the species from this group, increasing the knowledge about taxonomy of this group.

Metagenomics and metaproteomics reveal the effects of sludge types and inoculation modes on N,N-dimethylformamide degradation pathways and the microbial community involved

This study demonstrated the effects of the sludge type and inoculation method on the N,N-dimethylformamide degradation pathway and associated microbial communities. The sludge type is critical for DMF metabolism, with acclimatized aerobic sludge having a significant advantage in terms of DMF metabolism performance, whereas acclimatized anaerobic sludge has a reduced DMF metabolism capacity. Metagenomic revealed increased abundances of Methanosarcina, Pelomona and Xanthobacter in the adapted anaerobic sludge, suggesting that anaerobic sludge can utilize the methyl products produced by DMF metabolism for growth. Adapted aerobic sludge had high Mycobacterium abundance, significantly boosting DMF hydrolysis. In addition, a large number of dmfA2 genes were found in aerobic sludge, more so in acclimatized sludge, indicating stronger DMF metabolism. Conversely, acclimatized anaerobic sludge showed lower abundance of dmd-tmd and mauA/B, qhpA genes, implying long-term DMF toxicity reduced anaerobic microbial activity. Metaproteomic analysis showed that Methanosarcina and Methanomethylovorans enzymes in anaerobic sludge metabolized dimethylamine and methylamine to methane, aiding DMF degradation. In the aerobic sludge, aminohydrolase proteins, which hydrolyze DMF, were significantly upregulated. These findings provide insights into DMF wastewater treatment.

Highly sensitive and structure stable polyvinyl alcohol hydrogel sensor with tailored free water fraction and multiple networks by reinforcement of conductive nanocellulose

The wearable composite hydrogel sensors with high stretchability have attracted much attention in recent years, while the traditional hydrogels have weak molecular (chain) interaction and contain a lot of free water, leading to poor mechanical properties, unstable environmental tolerance and sensing ability. Herein, a novel ice crystal extrusion-crosslinking strategy is used to obtain polyvinyl alcohol (PVA) hydrogel with conductive nanocellulose-poly (3,4-ethylenedioxythiophene) (CNC-PEDOT) as skeleton network, sodium alginate (SA) and Ca2+ as tough segment of multi-bonding network. This strategy synergistically enhanced the interaction of hydrogen bonds and calcium (Ca2+) ion chelation within the hydrogel, building highly sensitive and stable multiple tough-elastic networks. Therefore, the optimal hydrogel sensor (PVA/SA-CP45) shows good structural stability, robust mechanical performance, excellent compress (Sensitivity = 68.7), stretching sensitivity (Gauge factor = 4.16), ultra-wide application range (-105-60 °C), fast response/relaxation time and outstanding dynamic durability with 6000 stretching-releasing cycles. Especially, it can give good sensing performance for omnidirectional monitoring of human motion and weak signals. Moreover, it was also designed into multifunctional sensing systems for gait guidance of model training and real-time monitoring ammonia gas for food preservation and public environmental safety, demonstrating great potential in flexible sensors devices for health monitoring.

Unveiling the long-term dynamic effects: Biochar mediates bacterial communities to modulate the petroleum hydrocarbon degradation in oil-contaminated sediments

Sediment, as the destination of marine pollutants, often bears much more serious petroleum pollution than water. Biochar is increasingly utilized for remediating organic pollutant-laden sediments, yet its long-term impacts on oil-contaminated sediment remain poorly understood. In this study, simulation experiments adding 2.5 wt% biochars (corn straw and wood chips biochar at different pyrolysis temperatures) were conducted. The effects on petroleum hydrocarbon attenuation, enzyme activities, and microbial community structure were systematically investigated. Results showed enhanced degradation of long-chain alkanes in certain biochar-treated groups. Biochar species and PAH characteristics together lead to the PAHs' attenuation, with low-temperature corn straw biochar facilitating the degradation of phenanthrene, fluorene, and chrysene. Initially, biochars reduced polyphenol oxidase activity but increased urease and dehydrogenase activities. However, there was a noticeable rise in polyphenol oxidase activity for a long time. Biochars influenced bacterial community succession and abundance, likely due to nutrient release stimulating microbial activity. The structural equations model (SEM) reveals that DON affected the enzyme activity by changing the microbial community and thus regulated the degradation of PAHs. These findings shed light on biochar's role in bacterial communities and petroleum hydrocarbon degradation over extended periods, potentially enhancing biochar-based remediation for petroleum-contaminated sediments.

Recent advances and prospects of neonicotinoid insecticides removal from aquatic environments using biochar: Adsorption and degradation mechanisms

In recent years, neonicotinoid insecticides (NNIs), representing a new era of pest control, have increasingly replaced traditional classes such as organophosphorus compounds, carbamates, and pyrethroids due to their precise targeting and broad-spectrum efficacy. However, the high water solubility of NNIs has led to their pervasion in aquatic ecosystems, raising concerns about potential risks to non-target organisms and human health. Therefore, there is an urgent need for research on remediating NNI contamination in aquatic environments. This study demonstrates that biochar, characterized by its extensive surface area, intricate pore structure, and high degree of aromaticity holds significant promise for removing NNIs from water. The highest reported adsorption capacity of biochar for NNIs stands at 738.0 mg·g-1 with degradation efficiencies reaching up to 100.0 %. This review unveils that the interaction mechanisms between biochar and NNIs primarily involve π-π interactions, electrostatic interactions, pore filling, and hydrogen bonding. Additionally, biochar facilitates various degradation pathways including Fenton reactions, photocatalytic, persulfate oxidations, and biodegradation predominantly through radical (such as SO4-, OH, and O2-) as well as non-radical (such as 1O2 and electrons transfer) processes. This study emphasizes the dynamics of interaction between biochar surfaces and NNIs during adsorption and degradation aiming to elucidate mechanistic pathways involved as well as assess the overall efficacy of biochar in NNI removal. By comparing the identification of degradation products and degradation pathways, the necessity of advanced oxidation process is confirmed. This review highlights the significance of harnessing biochar's potential for mitigating NNI pollution through future application-oriented research and development endeavors, while simultaneously ensuring environmental integrity and promoting sustainable practices.

Enhanced removal of 2,4-dichlorophenol by a novel biotic-abiotic hybrid system based on zeolitic imidazolate framework-8

Biotic-abiotic hybrid systems have recently emerged as a potential technique for stable and efficient removal of persistent contaminants due to coupling of microbial catabolic with abiotic adsorption/redox processes. In this study, Burkholderia vietnamensis C09V (B.V.C09V) was successfully integrated with a Zeolitic Imidazolate Framework-8 (ZIF-8) to construct a state-of-art biotic-abiotic system using polyvinyl alcohol/ sodium alginate (PVA/SA) as media. The biotic-abiotic system (PVA/SA-ZIF-8 @B.V.C09V) was able to remove 99.0 % of 2,4-DCP within 168 h, which was much higher than either PVA/SA, PVA/SA-ZIF-8 or PVA/SA@B.V.C09V (53.8 %, 72.6 % and 67.2 %, respectively). Electrochemical techniques demonstrated that the carrier effect of PVA/SA and the driving effect of ZIF-8 collectively accelerated electron transfer processes associated with enzymatic reactions. In addition, quantitative-PCR (Q-PCR) revealed that ZIF-8 stimulated B.V.C09V to up-regulate expression of tfdB, tfdC, catA, and catC genes (2.40-, 1.68-, 1.58-, and 1.23-fold, respectively), which encoded the metabolism of related enzymes. Furthermore, the effect of key physical, chemical, and biological properties of PVA/SA-ZIF-8 @B.V.C09V on 2,4-DCP removal were statistically investigated by Spearman correlation analysis to identify the key factors that promoted synergistic removal of 2,4-DCP. Overall, this study has created an innovative new strategy for the sustainable remediation of 2,4-DCP in aquatic environments.

Biochar supported Pseudomonas putida based globules for effective removal of Bisphenol A with a practical approach

The widespread and inevitable use of plastic has led to prospective ecological problems through Bisphenol A (BPA), a synthetic chemical in plastic manufacturing. The present study addresses a unique methodology for eliminating BPA using the assistance of Pseudomonas putida. In the present work, biomass was torrefied to generate biochar with highly porous networks that could accommodate the bacterial species for effective colonization and multiplication. The designed biochar-bacterial globules demonstrated the ability to effectively remove BPA (96.88%) at a concentration of up to 2 g/L. The biochar-bacterial globules could effectively adsorb BPA at a low concentration of 20 mg/L. The alteration in pH did not impact the globule's performance, providing additional support for the practical utilization of these globules in polluted water bodies. In addition, the biochar-bacterial globules exhibited superior effectiveness in degradation compared to the standard levels, particularly in saline conditions. The simplicity and effectiveness of the approach make it promising for real-world implementation in addressing ecological problems associated with BPA contamination.

Enhanced degradation of phthalate esters (PAEs) by biochar-sodium alginate immobilised Rhodococcus sp. KLW-1

In this study, a new strain of bacteria, named Rhodococcus sp. KLW-1, was isolated from farmland soil contaminated by plastic mulch for more than 30 years. To improve the application performance of free bacteria and find more ways to use waste biochar, KLW-1 was immobilised on waste biochar by sodium alginate embedding method to prepare immobilised pellet. Response Surface Method (RSM) predicted that under optimal conditions (3% sodium alginate, 2% biochar and 4% CaCl2), di (2-ethylhexyl) phthalate (DEHP) degradation efficiency of 90.48% can be achieved. Under the adverse environmental conditions of pH 5 and 9, immobilisation increased the degradation efficiency of 100 mg/L DEHP by 16.42% and 11.48% respectively, and under the high-stress condition of 500 mg/L DEHP concentration, immobilisation increased the degradation efficiency from 71.52% to 91.56%, making the immobilised pellets have strong stability and impact load resistance to environmental stress. In addition, immobilisation also enhanced the degradation efficiency of several phthalate esters (PAEs) widely existing in the environment. After four cycles of utilisation, the immobilised particles maintained stable degradation efficiency for different PAEs. Therefore, immobilised pellets have great application potential for the remediation of the actual environment.

Theoretical insights, degradation, and sub-lethal toxicity of thiamethoxam to the planarian Girardia tigrina

Advanced oxidative processes, such as Photo-Fenton, transform organic contaminants due to the attack by radicals. In this context, the lethal and sub-lethal effects of the Cruiser® 350FS (CRZ) with the active ingredient thiamethoxam (TMX) were investigated using the planarian Girardia tigrina. Degradation of thiamethoxam by the Fenton process was also assessed by using theoretical studies and the efficiency of Solar-Fenton versus Fenton. The 48 h LC50 value of CRZ for planarians was 478.6 mg L-1. The regeneration of planarians was significantly affected for concentrations ≥ 17 mg·L-1 of TMX (24 h). The Solar-Fenton showed a high degradation percentage reaching ~70%. The theoretical model showed the atoms of the TMX molecule that will suffer attacks from the formed radicals. Current results open new perspectives concerning the treatment of TMX in the aquatic environment because the 70% degradation seems to be sufficient to reach concentrations that do not induce sub-lethal effects in planarians. Further studies should determine if the by-products generated might be toxic for planaria or other organisms.

Remediation of petroleum-contaminated site soil by bioaugmentation with immobilized bacterial pellets stimulated by a controlled-release oxygen composite

Bioaugmentation techniques still show drawbacks in the cleanup of total petroleum hydrocarbons (TPHs) from petroleum-contaminated site soil. Herein, this study explored high-performance immobilized bacterial pellets (IBPs) embed Microbacterium oxydans with a high degrading capacity, and developed a controlled-release oxygen composite (CROC) that allows the efficient, long-term release of oxygen. Tests with four different microcosm incubations were performed to assess the effects of IBPs and CROC on the removal of TPHs from petroleum-contaminated site soil. The results showed that the addition of IBPs and/or CROC could significantly promote the remediation of TPHs in soil. A CROC only played a significant role in the degradation of TPHs in deep soil. The combined application of IBPs and CROC had the best effect on the remediation of deep soil, and the removal rate of TPHs reached 70%, which was much higher than that of nature attenuation (13.2%) and IBPs (43.0%) or CROC (31.9%) alone. In particular, the CROC could better promote the degradation of heavy distillate hydrocarbons (HFAs) in deep soil, and the degradation rates of HFAs increased from 6.6% to 33.2%-21.0% and 67.9%, respectively. In addition, the IBPs and CROC significantly enhanced the activity of dehydrogenase, catalase, and lipase in soil. Results of the enzyme activity were the same as that of TPH degradation. The combined application of IBPs and CROC not only increased the microbial abundance and diversity of soil, but also significantly enhanced the enrichment of potential TPH-biodegrading bacteria. M. oxydans was dominant in AP (bioaugmentation with addition of IBPs) and APO (bioaugmentation with the addition of IBPs and CROC) microcosms that added IBPs. Overall, the IBPs and CROC developed in this study provide a novel option for the combination of bioaugmentation and biostimulation for remediating organic pollutants in soil.

Microbial degradation mechanism and pathway of the insecticide thiamethoxam by isolated Bacillus Cereus from activated sludge

The high water solubility and ecotoxicity of thiamethoxam (TMX) is a potential hazard to ecosystems and human health. Here, a strain of Bacillus cereus with high TMX degradation activity was isolated from the sediment of the A2O process in the wastewater treatment plant and was able to utilize TMX as its sole carbon source. Under different environmental conditions, the degradation efficiency of TMX by Bacillus cereus-S1 (strain S1) ranged from 41.0% to 68.9% after 216 h. The optimum degradation conditions were DO = 3.5 mg/L and pH 9.0. The addition of an appropriate carbon-to-nitrogen ratio could accelerate the degradation of TMX. A plausible biodegradation pathway has been proposed based on the identified metabolites and their corresponding degradation pathways. TMX can be directly converted into Clothianidin (CLO), TMX-dm-hydroxyl and TMX-Urea by a series of reactions such as demethylation, oxadiazine ring cleavage and C=N substitution by hydroxy group. The main products were TMX-dm-hydroxyl and TMX-Urea, the amount of CLO production is relatively small. This study aims to provide a new approach for efficient degradation of TMX; furthermore, strain S1 is a promising biological source for in situ remediation of TMX contamination.

Anionic dye removal by immobilized bacteria into alginate-polyvinyl alcohol-bentonite matrix

Methyl orange (MO) is commonly used in the textile dyeing industry, posing serious health and environmental hazards due to its carcinogenic, mutagenic properties, and potential for bioaccumulation. Appropriate handling is needed to solve these problems by harnessing the capacity of living microorganisms and the adsorption properties of bentonite clay minerals. Although the conventional approach predominantly depends on free cells, recent study has developed other methods such as immobilization techniques. Therefore, this study aimed to investigate the efficiency of the immobilization matrix comprising sodium alginate (SA), polyvinyl alcohol (PVA), and bentonite by modifying Pseudomonas aeruginosa, Bacillus subtilis, and Ralstonia pickettii for MO removal of 50 mg/L. In the free cell technique, the results showed that the MO decreased to 43.13, 36.61, and 27.45% for each of the bacteria within 10 days at 35 °C. The bacterial immobilization technique, including live immobilized P. aeruginosa (LIPa), live immobilized B. subtilis (LIBs), and live immobilized R. pickettii (LIRp) beads also demonstrated significant efficiency, achieving MO removal rates up to 97.15, 95.65, and 66.63% within 10 days. These synthesized beads showed reusability, with LIPa, LIBs, and LIRp being used up to 4, 4, and 2 cycles, respectively. The external and internal surface conditions were observed using SEM instrument and the results showed that all components were agglomerated. Comparisons using dead bacterial biomass indicated that treatment with live bacteria consistently yielded significantly higher removal rates. These results showed the effectiveness of immobilized bacteria in MO removal, offering a promising potential in reducing pollutants.

Impact analysis of hydraulic residence time and dissolved oxygen on performance efficiency and microbial community in N, N-dimethylformamide wastewater treated by an AnSBR-ASBR

Suitable operating parameters are one of the key factors to efficient and stable biological wastewater treatment of N, N-dimethylformamide (DMF) wastewater. In this study, an improved AnSBR-ASBR reactor (anaerobic sequencing batch reactor, AnSBR, and aerobic SBR, ASBR, run in series) was used to investigated the effects of operating conditions such as hydraulic residence time (HRT), AnSBR stirring speed and ASBR dissolved oxygen (DO) for DMF wastewater treatment. When HRT decreased from 24 h to 12 h, the average removal rates of COD by the AnSBR were 34.59% and 39.54%, respectively. Meanwhile, the removal rate of NH4+-N by ASBR decreased from 88.38% to 62.81%. The DMF removal rate reached the best at 18 h and the expression of dehydrogenase was the highest in the AnSBR. The abundance of Megasphaera, the dominant sugar-degrading bacteria in the AnSBR, continued to decline due to the decrease of HRT. The relative abundance of Methanobacterium gradually increased to 80.2% with the decrease of HRT and that hydrotrophic methanogenesis dominated the methanogenic process. The HRT decrease promoted butyrate and pyruvate metabolism in anaerobic sludge, but the proportion of glycolysis and methane metabolism decreased. The AnSBR-ASBR reactor had the best operation performance when HRT was 18 h, AnSBR speed was 220 r/min, and ASBR DO content was 3-4 mg/L. This study provided an effective reference for the reasonable selection of operating parameters in the treatment of DMF-containing wastewater by the AnSBR-ASBR.

Mechanisms of adsorption and functionalization of biochar for pesticides: A review

Agricultural production relies heavily on pesticides. However, factors like inefficient application, pesticide resistance, and environmental conditions reduce their effective utilization in agriculture. Subsequently, pesticides transfer into the soil, adversely affecting its physicochemical properties, microbial populations, and enzyme activities. Different pesticides interacting can lead to combined toxicity, posing risks to non-target organisms, biodiversity, and organism-environment interactions. Pesticide exposure may cause both acute and chronic effects on human health. Biochar, with its high specific surface area and porosity, offers numerous adsorption sites. Its stability, eco-friendliness, and superior adsorption capabilities render it an excellent choice. As a versatile material, biochar finds use in agriculture, environmental management, industry, energy, and medicine. Added to soil, biochar helps absorb or degrade pesticides in contaminated areas, enhancing soil microbial activity. Current research primarily focuses on biochar produced via direct pyrolysis for pesticide adsorption. Studies on functionalized biochar for this purpose are relatively scarce. This review examines biochar's pesticide absorption properties, its characteristics, formation mechanisms, environmental impact, and delves into adsorption mechanisms, functionalization methods, and their prospects and limitations.

Improved treatment of coking wastewater and higher biodiversity through immobilization of Comamonas sp. ZF-3 supplemented microbial community

The aim of this study was to investigate the relationship among pollutant removal performance, microbial community structure, and potential gene function of immobilized microorganisms in coking wastewater (CWW) treatment process. The results showed that the immobilized biomass containing strain Comamonas sp. ZF-3 displayed greater resistance to CWW and higher COD, NH4+-N removal efficiency (92%, 60%) than free cells (48%, 7%), meanwhile, the results from GC-MS proved main organic pollutants in CWW including phenolic compounds, heterocyclic compounds, and polycyclic aromatic hydrocarbons were basically removed by immobilized microorganisms. During 123 days of degradation experiment, high-throughput 16S rRNA gene sequencing analysis of immobilized carriers showed more stable and diverse microbial community, which was consistent with simultaneous removal of COD and NH4+-N observed in carrier experiment. Among them, Comamonas sp. ZF-3 continuously remained at the highest proportion (23.25%) in immobilized carrier, while Nitrosomonas (1.47%) and Nitrospira (1.90%) were simultaneously detected. Moreover, microbial community of immobilized carriers showed higher relative abundance of potential function in membrane transport and xenobiotics biodegradation and metabolism, which may indirectly displayed biodegradation activity of immobilized functional microorganisms. This work illustrated the survival status and potential gene function of immobilized microorganisms, and provided basis for practical application of immobilized carriers in CWW treatment.

Poly(vinyl alcohol)/modified porous starch gel beads for microbial preservation and reactivation: preparation, characterization and its wastewater treatment performance

Poly(vinyl alcohol) (PVA)/modified porous starch (MPS) gel beads were prepared through in situ chemical cross-linking by incorporating with MPS, which was obtained by modifying porous starch (PS) with polyethyleneimine (PEI) and glutaraldehyde (GA). Addition of MPS could improve the storage modulus and the effective crosslinking density (ve) of the gel beads, and the mechanical properties were enhanced. The PVA-MPS gel beads were preserved as immobilized microbial carriers for 40 d and reactivated in wastewater. Scanning electron microscope (SEM) observations showed that the beads were highly porous and conducive for microorganism adhesion. The PVA-MPS gel beads were able to remove 97% of ammonia nitrogen and 80% of chemical oxygen demand (COD) after reactivation under all four preservation conditions. The abundance of Hydrogenophaga as denitrifying bacteria on PVA-MPS gel beads increased, with abundance of 8.44%, 5.55%, 8.90% and 9.48%, respectively. It proved that the carrier provided a partial hypoxic environment for microorganisms.

Efficient pyridine biodegradation by Stenotrophomonas maltophilia J2: Degradation performance, mechanism, and immobilized application for wastewater

Stenotrophomonas maltophilia J2, a highly efficient pyridine-degrading bacterium, was isolated from the aerobic tank of a pesticide-contaminated wastewater treatment plant. The strain J2 demonstrated an impressive pyridine degradation rate of 98.34% ± 0.49% within 72 h, at a pyridine concentration of 1100 mg·L-1, a temperature of 30 °C, a pH of 8.0, and a NaCl concentration of 0.5%. Notably, two new pyridine metabolic intermediates, 1,3-dihydroxyacetone and butyric acid, were discovered, indicating that J2 may degrade pyridine through two distinct metabolic pathways. Furthermore, the immobilized strain J2 was obtained by immobilizing J2 with biochar derived from the stem of Solidago canadensis L. In the pyridine-contaminated wastewater bioremediation experiment, the immobilized strain J2 was able to remove 2000 mg·L-1 pyridine with a 98.66% ± 0.47% degradation rate in 24 h, which was significantly higher than that of the control group (3.17% ± 1.24%), and remained above 90% in subsequent cycles until the 27th cycle. High-throughput sequencing analysis indicated that the J2 +B group had an elevated relative abundance of bacteria and functional genes that could be associated with the degradation of pyridine. The results offer a foundation for the effective use of immobilized strain in the treatment of recalcitrant pyridine-contaminated wastewater.

Efficient antibacterial and dye adsorption by novel fish scale silver biochar composite gel

A silver-loaded carbon-chitosan-polyvinyl alcohol gel (C/CTS/PVA) was designed for suppressing microbial growth and dye adsorption. The antibacterial test results showed that C/CTS/PVA gel had a good antibacterial ability against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. The inhibition rate in water was 100 %, and the antibacterial rate remained above 95 % within 35 days after preparation. The tight spatial structure provided by the adhesive effect of PVA and CTS effectively prevented water loss and enhanced the stability of the gel. The adsorption curves of the gel were fitted by establishing the pseudo-first order and pseudo-second order kinetic models. The adsorption curves were more consistent with the pseudo-second-order kinetic model. The best adsorption effect for Malachite green was 128.12 mg/g. C/CTS/PVA gel had a remarkable adsorption effect on Malachite green, Congo red, Methyl orange, and Methylene blue. In general, C/CTS/PVA gels have great potential for the treatment of sewage in the future.

Chryseobacterium herbae Isolated from the Rhizospheric Soil of Pyrola calliantha H. Andres in Segrila Mountain on the Tibetan Plateau

A non-motile, Gram-staining-negative, orange-pigmented bacterium called herbae pc1-10T was discovered in Tibet in the soil around Pyrola calliantha H. Andres' roots. The isolate thrived in the temperature range of 10-30 °C (optimal, 25 °C), pH range of 5.0-9.0 (optimum, pH = 6.0), and the NaCl concentration range of 0-1.8% (optimal, 0%). The DNA G+C content of the novel strain was 37.94 mol%. It showed the function of dissolving organophosphorus, acquiring iron from the environment by siderophore and producing indole acetic acid. Moreover, the genome of strain herbae pc1-10T harbors two antibiotic resistance genes (IND-4 and AdeF) encoding a β-lactamase, and the membrane fusion protein of the multidrug efflux complex AdeFGH; antibiotic-resistance-related proteins were detected using the Shotgun proteomics technology. The OrthoANIu values between strains Chryseobacterium herbae pc1-10T; Chryseobacterium oleae CT348T; Chryseobacterium kwangjuense KJ1R5T; and Chryseobacterium vrystaatense R-23566T were 90.94%, 82.96%, and 85.19%, respectively. The in silico DDH values between strains herbae pc1-10T; C. oleae CT348T; C. kwangjuense KJ1R5T; and C. vrystaatense R-23566T were 41.7%, 26.6%, and 29.7%, respectively. Chryseobacterium oleae, Chryseobacterium vrystaatense, and Chryseobacterium kwangjuense, which had 16S rRNA gene sequence similarity scores of 97.80%, 97.52%, and 96.75%, respectively, were its closest phylogenetic relatives. Chryseobacterium herbae sp. nov. is proposed as the designation for the strain herbae pc1-10T (=GDMCC 1.3255 = JCM 35711), which represented a type species based on genotypic and morphological characteristics. This study provides deep knowledge of a Chryseobacterium herbae characteristic description and urges the need for further genomic studies on microorganisms living in alpine ecosystems, especially around medicinal plants.

State of Innovation in Alginate-Based Materials

This review article presents past and current alginate-based materials in each application, showing the widest range of alginate's usage and development in the past and in recent years. The first segment emphasizes the unique characteristics of alginates and their origin. The second segment sets alginates according to their application based on their features and limitations. Alginate is a polysaccharide and generally occurs as water-soluble sodium alginate. It constitutes hydrophilic and anionic polysaccharides originally extracted from natural brown algae and bacteria. Due to its promising properties, such as gelling, moisture retention, and film-forming, it can be used in environmental protection, cosmetics, medicine, tissue engineering, and the food industry. The comparison of publications with alginate-based products in the field of environmental protection, medicine, food, and cosmetics in scientific articles showed that the greatest number was assigned to the environmental field (30,767) and medicine (24,279), whereas fewer publications were available in cosmetic (5692) and food industries (24,334). Data are provided from the Google Scholar database (including abstract, title, and keywords), accessed in May 2023. In this review, various materials based on alginate are described, showing detailed information on modified composites and their possible usage. Alginate's application in water remediation and its significant value are highlighted. In this study, existing knowledge is compared, and this paper concludes with its future prospects.

Determining the degradation mechanism and application potential of benzopyrene-degrading bacterium Acinetobacter XS-4 by screening

In industrial wastewater treatment, organic pollutants are usually removed by in-situ microorganisms and exogenous bactericides. Benzo [a] pyrene (BaP) is a typical persistent organic pollutant and difficult to be removed. In this study, a new strain of BaP degrading bacteria Acinetobacter XS-4 was obtained and the degradation rate was optimized by response surface method. The results showed that the degradation rate of BaP was 62.73% when pH= 8, substrate concentration was 10 mg/L, temperature was 25 °C, inoculation amount was 15% and culture rate was 180 r/min. Its degradation rate was better than that of the reported degrading bacteria. XS-4 is active in the degradation of BaP. BaP is degraded into phenanthrene by 3, 4-dioxygenase (α subunit and β subunit) in pathway Ⅰ and rapidly forms aldehydes, esters and alkanes. The pathway Ⅱ is realized by the action of salicylic acid hydroxylase. When sodium alginate and polyvinyl alcohol were added to the actual coking wastewater to immobilize XS-4, the degradation rate of BaP was 72.68% after 7 days, and the removal effect was better than that of single BaP wastewater (62.36%), which has the application potential. This study provides theoretical and technical support for microbial degradation of BaP in industrial wastewater.

More effective application of biochar-based immobilization technology in the environment: Understanding the role of biochar

In recent years, biochar-based immobilization technology (BIT) has been widely used to treat different environmental issues because of its cost-effectiveness and high removal performance. However, the complexity of the real environment is always ignored, which hinders the transfer of the BIT from lab-scale to commercial applications. Therefore, in this review, the analysis is performed separately on the internal side of the BIT (microbial fixation and growth) and on the external side of the BIT (function) to achieve effective BIT performance. Importantly, the internal two stages of BIT have been discussed concisely. Further, the usage of BIT in different areas is summarized precisely. Notably, the key impacts were systemically analyzed during BIT applications including environmental conditions and biochar types. Finally, the suggestions and perspectives are elucidated to solve current issues regarding BIT.

Beads for Cell Immobilization: Comparison of Alternative Additive Manufacturing Techniques

The attachment or entrapment of microbial cells and enzymes are promising solutions for various industrial applications. When the traps are beads, they are dispersed in a fluidized bed in a vessel where a pump guarantees fresh liquid inflow and waste outflow without washing out the cells. Scientific papers report numerous types of cell entrapment, but most of their applications remain at the laboratory level. In the present research, rigid polymer beads were manufactured by two different additive manufacturing (AM) techniques in order to verify the economy, reusability, and stability of the traps, with a view toward a straightforward industrial application. The proposed solutions allowed for overcoming some of the drawbacks of traditional manufacturing solutions, such as the limited mechanical stability of gel traps, and they guaranteed the possibility of producing parts of constant quality with purposely designed exchange surfaces, which are unfeasible when using conventional processes. AM proved to be a viable manufacturing solution for beads with complex shapes of two different size ranges. A deep insight into the production and characteristics of beads manufactured by AM is provided. The paper provides biotechnologists with a manufacturing perspective, and the results can be directly applied to transit from the laboratory to the industrial scale.