Reviews in Environmental Science and Bio/Technology最新文献

Per- and polyfluoroalkyl substances (PFAS) are highly persistent organic pollutants due to their strong C–F bonds, which contribute to their environmental persistence and associated health risks. Naturally-occurring microbes have the ability to degrade PFAS, with Pseudomonas genus showing the highest efficiency, including Pseudomonas plecoglossicida (75%) and Pseudomonas aeruginosa (67%), which has received much attention. This review explores the underlying mechanisms during microbial PFAS degradation, emphasizing bond cleavage processes, including C–F and C–Cl bonds, and the critical roles of microbial enzymes. Microorganisms utilize specialized metabolic strategies to actively cleave chemical bonds within PFAS molecules, initiating their breakdown. Additionally, microorganisms secrete specific enzymes, which play pivotal roles in catalyzing PFAS degradation. Microorganisms and their enzymes can transform and/or defluorinate PFAS through different metabolic processes, improving the efficiency of PFAS degradation. This review further explores the current challenges in PFAS biodegradation and outlines future research directions, aiming to help future studies overcome these obstacles and drive progress in this field.

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Microcystin, a potent cyanobacterial toxin, poses a potential health risk to humans through exposure to recycled water used for food crop irrigation. This comprehensive review synthesizes current knowledge on microcystin uptake and accumulation in various food crops, assessing associated health risks based on reported toxin levels and tolerable daily intake values. The impact of wastewater irrigation on microcystin uptake is also evaluated. Our analysis reveals critical knowledge gaps, highlighting key research priorities for ensuring food safety and mitigating human exposure to microcystin. Future studies should address these gaps to inform evidence-based guidelines for safe recycled water use in agriculture.

⁹⁹Tc is primarily released in spent nuclear fuel reprocessing, mainly exists as ({text{TcO}}_{4}^{-}) anions in aqueous solution, while its removal still remains a challenge due to its complex chemical behavior. Among various methods, adsorption stands out for its low cost and high selectivity. This review focuses on emerging nanomaterials, including covalent organic frameworks (COFs), metal–organic frameworks (MOFs), cationic polymer networks (CPNs), MXenes, layered double hydroxides (LDHs), and nano zero-valent iron (nZVI), for ⁹⁹Tc removal through adsorption. The adsorption performance and mechanism of these nanomaterials for ({text{TcO}}_{4}^{-}) removal were critically reviewed. Additionally, these nanomaterials’ irradiation stability and reusability were also assessed. Finally, the challenges and future research directions are discussed, offering insights into enhancing the practical application of these materials for radioactive wastewater treatment.

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Dissimilatory nitrate reduction to ammonium (DNRA) is important for nitrogen retention in ecosystems and is in competition with denitrification. However, denitrification tends to dominate. A high organic carbon content and limited nitrate are the key conditions for DNRA to outcompete denitrification, but the mechanisms for controlling the nitrate fate are not well understood. This review systematically summarizes the processes of and correlation between DNRA and denitrification, with a focus on outlining the characteristics of the active enzymes, including the enzyme structure, substrate affinity, and electron transfer. The competitive advantage of DNRA for electron acceptors are highlighted and discussed from enzymatic and kinetic perspectives. The high electron acquisition of DNRA causes it to dominate nitrate removal under nitrate limitation. Finally, strategies for promoting environmental nitrogen retention through DNRA are proposed, and possible directions for future research are suggested. This review aims to improve understanding of the competitive mechanisms of DNRA and denitrification and to promote the application and development of DNRA as a sustainable nitrogen retention strategy.

During the preparation of alcohol from grains, substantial amounts of value-added byproducts, known as distillers' grains, are generated. These byproducts are rich in nutrients, including dietary fiber (hemicellulose, cellulose, and lignin), protein, simple sugars (glucose, xylose, and arabinose), minerals, vitamins, and lipids. However, the rapid global expansion of the alcohol industry has resulted in tens of thousands of tons of distillers' grains remaining without appropriate disposal methods. Therefore, it is essential to identify innovative solutions that reintegrate waste and byproducts into the production cycle, thereby yielding high-quality products. In this review, we first summarize the classification, sources, and components of distillers' grains. We then analyze and compare their utilization value and extraction technologies, as well as their development and market status. Additionally, we summarize the categories of active substances found in distillers' grains and assess the current status and potential applications for resource recycling. Ultimately, this review aims to provide insights into the reuse of various active ingredients in different types of distillers' grains, contributing to the reduction of carbon emissions and achieving a balance of economic, environmental, and social benefits worldwide.

Insensitive munitions compounds (IMCs), such as 2,4-dinitroanisole (DNAN), 3-nitro-1,2,4-triazol-5-one (NTO) and nitroguanidine (NQ), are replacing conventional explosives due to their higher detonation temperatures and greater resistance to mechanical shocks, making them safer for handling and storage. IMCs can contaminate the environment through the dissolution of undetonated residues in military training ranges or the discharge of wastewater from IMCs manufacturing. Developing remediation strategies has become imperative, given the toxicity and, in some cases, carcinogenicity of IMCs or their transformation products. Bioremediation offers a cost-effective method to treat IMCs, potentially converting hazardous contaminants into harmless products. Recent years have seen a surge in research focused on various strategies for IMCs bioremediation. Thus, a review becomes imperative to consolidate findings and guide future research in this field. This work aims to provide the first comprehensive guidelines for the microbial remediation of IMCs and their transformation products. It starts by explaining the mechanisms involved in anaerobic biotransformation and aerobic mineralization of IMCs. It then explores different types of bioreactor systems used for treating both individual IMCs and their mixtures. Finally, it provides potential bioremediation approaches for handling wastewater from munitions manufacturing facilities and addressing groundwater and soil contaminated by IMCs. The focus is to support scientists, engineering consultants, and site remediation managers in developing and optimizing effective microbial remediation strategies for IMCs contamination.

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As an emerging pollutant, per- and polyfluoroalkyl substances (PFAS) are ubiquitous in water and pose a great risk to humans. Adsorption technology is a promising technology for removing PFAS, but efficient adsorbents are still needed. Newly developed nanoporous crystalline materials, metal–organic frameworks (MOFs) and covalent organic frameworks (COFs), exhibit significant promise for the adsorptive removal of PFAS pollution, but there is still a lack of relevant reviews. Therefore, this review mainly focused on MOFs and COFs’ adsorption performance and mechanisms towards PFAS. Hydrophobic and electrostatic interactions take part in the process of PFAS adsorption, while ion exchange, hydrogen bonding, and Lewis acid–base complexation are also concluded. The novelty of this work lies in the comparison of MOFs and COFs in terms of PFAS’s adsorptive removal. Future suggestions for the improved utility of MOFs and COFs were also given.

Fruit production is a pivotal sector of the human diet and world economy. Oranges, bananas, and guava stand out as some of the most widely produced fruits either for direct consumption or industrial processing. Consequently, an environmental problem arises from the waste disposal generated throughout these fruits’ life cycle. Seeds, bagasse, leaves, peel, and the fruit itself are the main residues found, all lignocellulosic biomasses composed mainly of cellulose, hemicellulose, and lignin, in addition to pectin as a minor component. Thus, fruit waste biomass has been investigated for obtaining macromolecules and derivatives as building blocks for several value-added applications within the biorefinery/bioenergy field such as xylooligosaccharides, xylan and pectin-based bioplastics, biofuel, biogas, electrochemical sensors, nanocomposites, among others. However, when it comes to lignin from fruit waste, there is an enormous unexplored potential compared to other feedstocks, especially wood and gramineous plants. This review addresses the lignocellulosic composition of orange, banana, and guava fruit waste, pretreatments, and recent applications, to assist and foment future research on waste biomass conversion.

In the environmental cycle of mercury (Hg), plants link the atmosphere, soil sphere, hydrosphere, and biosphere, serving as important sites for Hg transformation and translocation across these domains. The absorption and migration of Hg by plants play a critical role in the natural or environmental cycle of Hg. In this review, we outlined the existing technical methods for studying Hg behaviours involving plants, summarized the uptake pathways of Hg by different plant tissues from the environment, analyzed the transformation processes of Hg in plants and its various migration pathways, and demonstrated the changes in the source-sink relationship of Hg between plants and the environment. Additionally, we highlight knowledge gaps in existing research concerning the mechanisms of Hg transformation processes in plants, the role of marine plants in the environmental cycle of Hg, and the impact of global change on Hg cycle. This study aims to provide a comprehensive overview of current research on the relationship between Hg and plants, facilitating a quick understanding of the research progress and highlighting potential directions for future studies.

Biochar is a carbon-rich material produced through the pyrolysis of organic biomass. Its unique properties make it a versatile asset in agricultural and environmental management. This review paper provides scientific insights into how biochar affects soil’s physical, chemical, and biological properties. It then discusses how these changes can impact crop growth and yield, addressing a key concern for farmers while also considering the potential for biochar to mitigate greenhouse gas (GHG) emissions such as carbon dioxide (CO₂), Nitrous oxide (N₂O), and methane (CH₄), which is of public interest. Additionally, it examines the costs and benefits associated with biochar use, aiming to guide its adoption and suggest future research directions in agricultural applications. Biochar incorporation improves soil properties by enhancing structure, water retention, aeration, nutrient availability, and microbial activity. Different processes impact the effects of biochar on soil, plants, and agricultural systems, influenced by factors like biochar type, soil type, and application rate. Understanding the interaction of these elements, especially over the long term, is vital for promoting the widespread use of biochar in agriculture. Moreover, assessing the economic benefits and costs of biochar in each region is key to convincing farmers to adopt this practice.

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