Biodegradation最新文献

Vapor intrusion (VI) happens when volatile organic compounds (VOCs) migrate from subsurface sources into buildings, harming indoor air quality and occupants’ health. To investigate the migration and biodegradation of volatile organic compounds (VOCs) originating from subsurface sources, a soil column experiment was performed. In this experiment, high-concentration vapor from the liquid phase of toluene was steadily released into silty sand soil, aiming to simulate the conceptual model of a specific site. The experimental findings revealed that, within the silty sand soil, it took 36 h for toluene vapors to diffuse through a 120-cm-long soil column. During this process, the volume fractions of O₂ and CO₂ within the soil column varied. The level of microbial activity in the soil column first rose and then declined, as did the abundance of the dominant degrading toluene bacteria group. The experiment demonstrated that covering a certain thickness of silty sand soil could effectively retard the migration of toluene vapor. In addition, biodegradation occurred during the migration of the toluene vapor. However, long-term exposure to high-concentration toluene vapors inhibited both the activity and growth of microorganisms within the soil column.

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Hyperuricemia (HUA) caused by high serum uric acid (UA) level can lead to a range of metabolic diseases, such as gout, cardiovascular disease and diabetes. The reduction of crucial UA precursors of both inosine and guanosine is a potential method to control HUA. Here a promising bacterial strain for biodegrading both inosine and guanosine were successfully isolated from Baijiu cellar mud and identified as Lysinibacillus fusiformis-YC01 by ANI analysis. Initial 490 mg/L of inosine and 612 mg/L of guanosine were completely biodegraded by YC01 within 18 h at 38 °C. In addition, the initial 357 mg/L of inosine and 365 mg/L of guanosine were also removed by the cell-free extracts of YC01 at a protein concentration of 0.13 mg/mL within 16 h. Furthermore, the whole genome analysis of YC01 revealed that purine nucleoside phosphorylase and purine nucleosidase played key roles in the biodegradation of inosine and guanosine, which encoded by gene deoD and gene iunH. These findings indicated that YC01 could biodegrade inosine and guanosine, and provided the new valuable insights into microbial removal of UA precursors for the amelioration of HUA.

This study explored the ability of two Bacillus species isolated from mangrove sediments to degrade hexachlorobenzene (HCB), a persistent organic pollutant that affects the quality of surface water, groundwater, and soil. Hence, we analyzed bacterial growth in a medium with hexachlorobenzene as the sole carbon source. Moreover, chemical oxygen demand removal, ecotoxicity, and measured radiolabeled HCB degradation were assessed. Our results revealed that both Bacillus strains (I3 and I6) demonstrated hexachlorobenzene-degrading potential and achieved degradation rates of 11.5 ± 1.47% and 21.1 ± 0.84%. Additionally, the ability of these strains to mineralize HCB was confirmed by the production of radiolabeled carbon dioxide, assessed by liquid scintillation spectrometry and thin-layer chromatography. Ecotoxicity assays further demonstrated the effectiveness of bacteria treatment in degrading HCB. These findings underscore the potential of Bacillus strains from mangrove sediments to degrade and mineralize HCB, opening new perspectives for the bioremediation of aromatic compounds in contaminated environments.

The disposal of plastic materials has resulted in the huge increase of microplastics in the environment. One of the most hazardous plastic waste is polyvinyl chloride (PVC) due to its durability. A tool to remediate PVC microplastic polluted environment might be offered by microorganisms such as Actinobacteria, which has been proven to degrade PVC. Streptomyces gobitricini was isolated from soil polluted by heavy metals and plastic debris and used in a PVC microplastics degradation experiment. Fourier-transform infrared spectroscopy (FT-IR), Raman spectroscopy, and scanning electron microscopy (SEM) were used to study the characteristics of microplastic particles. For the incubation, the optimal pH 7.5 was determined in a preliminary experiment where also pH 5.5 and pH 9.5 were included. Three PVC concentrations (200, 400, and 800 mg/L) were incubated in Luria–Bertani broth with S. gobitricini for 90 days. After the incubation, PVC-MP particles were recovered by filtering. The percentual weight loss of microplastics was highest (66%) in 200 mg/L treatment. Relatively high reductions were observed for the higher microplastic concentrations as well (400 mg/L; 65% and 800 mg/L; 60%). The bacterial growth decreased in order 200 mg/L (3.1 ± 0.1 CFU × 10⁵/mL), 400 mg/L (3.0 ± 0.0 CFU × 10⁵/mL) and 800 mg/L treatment (2.7 ± 0.0 CFU × 10⁵/mL). High hydrophobicity was observed in all treatments at the end of the incubation indicating the formation of bacterial biofilm on the surfaces of plastic particles. The highest hydrophobicity (84%) associated with the bacterial strain was observed in 200 mg/L microplastics treatment. The results show that the bacterium S. gobitricini suits for further studies to reduce PVC microplastic waste in the environment.

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In recent years, it has become important for a sustainable environment that clothes are biodegradable, and that unused clothing does not pollute the environment by decomposing in nature. Cotton, especially organic cotton, can decompose very quickly in nature. Since organic clothing production has become important in recent years, the seam performance and biodegradability of these products, unlike conventional products, are important in creating new data for the textile and clothing industry. This paper presents an experimental study of the seam performance and biodegradability properties of organic clothes for their sustainability. In this study, six groups of fabrics with a plain weave structure were produced to examine the seam performance and biodegradability of clothes made of organic cotton woven fabrics. Each group includes three different samples of the fabric: conventional cotton fabric dyed with reactive dyes, organic cotton fabric dyed with reactive dyes, and organic cotton fabric dyed with natural dye. Therefore 18 samples having different properties were obtained. Fabric breaking strength, seam strength, seam efficiency and biodegradability tests of these fabric samples were determined. Sample women's blouses were sewn from the fabric samples used in the experimental study, and the blouse appearances were visually presented on the mannequin.

Polyhydroxyalkanoates (PHAs) are promising polymer in the battle against plastic pollution. Here, Rhodococcus qingshengii LS18 bacterial strain recovered from abattoir soil was identified as significant PHA producer (2.16 g/L PHA). Amongst five animal wastes tested, chicken feathers (2.2 g/L) were found to be best for PHA production from R. qingshengii LS18. Finest conditions for PHA production after statistical optimization were found at 120 h with 40 g/L chicken feathers and 1 g/L urea at 80 rpm which showed 2.6 times increment in PHA production as compared to One-factor-at-a-time optimization (OFAT). The extracted PHA was analysed using NMR, FTIR, XRD and GCMS. The melting temperature (T_m) of microbial PHA was recorded at 176.63 °C as per DSC analysis and this polymer suffered complete disintegration at ~ 300 °C as per the TGA profile which is better than the standard PHA (~ 283.14 ± 10 °C). Blending of microbial PHA was done to overcome the brittleness with sole extracted PHA and for better degradation capability. Best PHA blend obtained with gelatin and Egg shell powder (ESP) in ratio 2:1:1 where 94% Elongation at break, 62% Elongation at max load and 9.81 MPa Tensile strength was found. Here, biodegradation rate of PHA blend in unaltered garden soil (at 30–40 °C, humidity ~ 30%, pH 7.4) was recorded to be 94% on 60th day of soil burial experiment. The study concludes that R. qingshengii LS18 is a promising PHA producer having the ability to utilize chicken feathers in optimised conditions and can be used for packaging applications in the form of PHA blends.

Mycoremediation is a biological treatment approach that relies on fungi to transform environmental pollutants into intermediates with lower environmental burden. Basidiomycetes have commonly been used as the target fungal phylum for bioaugmentation in mycoremediation, however this phylum has been found to be unreliable when used at scale in the field. In this study, we isolated, characterized, and identified potential polycyclic aromatic hydrocarbon (PAH) degrading fungal isolates from creosote-contaminated sediment in the Elizabeth River, Virginia. Our goal was to identify non-basidiomycete PAH degrading fungi. A total of 132 isolates were isolated, of which the overwhelming majority belonged to the phylum Ascomycota. Isolates were screened for their ability to produce known PAH degrading enzymes, particularly laccase and manganese-dependent peroxidases, and to transform model PAH compounds [fluoranthene, phenanthrene, pyrene and benzo(a)pyrene]. Fungal isolates were subsequently biostimulated using complex amendments including chicken feathers, wheat seeds, grasshoppers, and maple saw dust. Following biostimulation, laccase expression and PAH transformation were assessed. The grasshopper amendment was found to yield the highest laccase upregulation improvement with a maximum increase of 18.9% for the Paraphaeosphaeria isolate. The Septoriella and Trichoderma isolates exposed to the chitin-based grasshopper amendment demonstrated an increase in PAH removal. Septoriella sp. increased its transformation of fluoranthene (44%), pyrene (54.2%, and benzo(a)pyrene (48.7%), while there was a 58.3% increase in the removal of benzo(a)pyrene by Trichoderma sp. While the results from this study demonstrate the potential of indigenous fungi to be biostimulated for the removal of PAHs, additional investigation is needed to determine if the response to the chitin-based grasshopper mycostimulation can be translated from the bench to the field.

Bioplastics, particularly polyhydroxyalkanoates (PHAs), are emerging as promising alternatives to traditional materials due to their biodegradability. This study focuses on the production of PHAs as bioplastics using effluent from hydrogen production in a two-stage Biohythane Pilot Plant, which provides a low-cost substrate. The aim is to optimize production conditions, with Cupriavidus necator TISTR 1335 being used as the PHA producer. Utilizing Response Surface Methodology-Central Composite Design, we explored optimal conditions, revealing peak PHA production at a substrate concentration of 33.51 g COD/L and a pH of 6.87. The predicted optimal PHA concentration was at 3.05 g/L within the established model, closely matching the experimentally validated value of 3.02 g/L, with the overall usage rate of reducing sugars approximately 50–60%. This study underscores the importance of optimizing PHA production conditions and paving the way toward large-scale PHA production.

Per- and polyfluoroalkyl substances (PFAS) are synthetic organofluoride compounds, widely used in industries since the 1950s for their hydrophobic properties. PFAS contamination of soil and water poses significant environmental and public health risks due to their persistence, chemical stability, and resistance to degradation. The Chemical Abstracts Service catalogs approximately 4300 PFAS globally. Research in various regions such as North America, Asia, Europe, and remote polar zones has revealed the accumulation of perfluorooctane sulfonate (PFOS) in the tissues of various animal species, with concentrations reaching up to 1900 ng/g in aquatic species like dolphins and whales. Researchers have employed various remediation techniques such as solvent extraction, ion exchange, precipitation, adsorption, and membrane filtration, each of which has its drawbacks. Adsorption, particularly using waste-derived functional materials like biochar, is emerging as a promising method for PFAS remediation due to its cost-effectiveness and sustainability. For example, waste timber-derived biochar exhibits adsorption efficiency comparable to commercial activated carbon. This review highlights advancements in using agricultural, industrial, and biological waste-derived materials for sustainable PFAS remediation. We discuss innovative modification techniques like hydrothermal synthesis, pyrolysis, calcination, co-precipitation, the sol–gel method, and ball milling. The study also examines adsorption mechanisms, factors affecting adsorption efficiency, and the technological challenges in scaling up waste-derived material use. It aims to explore developments, challenges, and future directions for using these materials for efficient PFAS remediation and contributing to sustainable environmental cleanup solutions.

This study aims to investigate the biodegradation potential of a gut bacterial strain, Bacillus cereus AP-01, isolated from Tenebrio molitor larvae fed Styrofoam, focusing on its efficacy in degrading low-density polyethylene (LDPE). The biodegradation process was evaluated through a series of assays, including clear zone assays, biodegradation assays, and planktonic cell growth assessments in mineral salt medium (MSM) over a 28-day incubation period. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were employed to characterize the alterations in LDPE pellets, followed by molecular characterization. Over three months, sterile soil + LDPE pellets were treated with different concentrations of gut bacterial strain. The degradation capabilities were assessed by measuring pH, total microbial counts, carbon dioxide evolution, weight loss, and conducting phase contrast microscopy and mechanical strength tests. Results demonstrated that MSM containing LDPE as a carbon source with gut bacterial strain produced a clear zone and enhanced planktonic cell growth. FTIR analysis revealed the formation of new functional groups in the LDPE, while SEM images displayed surface erosion and cracking, providing visual evidence of biodegradation. Molecular characterization confirmed the strain as Bacillus cereus AP-01 (NCBI Accession Number: OR288218.1). A 10% inoculum concentration of Bacillus cereus AP-01 exhibited increased soil bacterial counts, carbon dioxide evolution, and pH levels, alongside a notable weight loss of 30.3% in LDPE pellets. Mechanical strength assessments indicated substantial reductions in tensile strength (7.81 ± 0.84 MPa), compression (4.92 ± 0.53 MPa), hardness (51.96 ± 5.62 shore D), flexibility (10.62 ± 1.15 MPa), and impact resistance (14.79 ± 0.94 J). These findings underscore the biodegradation potential of Bacillus cereus AP-01, presenting a promising strategy for addressing the global LDPE pollution crisis.

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