Reviews in Environmental Science and Bio/Technology最新文献

Despite significant public health concerns regarding infectious diseases in air environments, potentially harmful microbiological indicators, such as antibiotic resistance genes (ARGs) in bioaerosols, have not received significant attention. Traditionally, bioaerosol studies have focused on the characterization of microbial communities; however, a more serious problem has recently arisen due to the presence of ARGs in bioaerosols, leading to an increased prevalence of horizontal gene transfer (HGT). This constitutes a process by which bacteria transfer genes to other environmental media and consequently cause infectious disease. Antibiotic resistance in water and soil environments has been extensively investigated in the past few years by applying advanced molecular and biotechnological methods. However, ARGs in bioaerosols have not received much attention. In addition, ARG and HGT profiling in air environments is greatly limited in field studies due to the absence of suitable methodological approaches. Therefore, this study comprehensively describes recent findings from published studies and some of the appropriate molecular and biotechnological methods for monitoring antibiotic resistance in bioaerosols. In addition, this review discusses the main knowledge gaps regarding current methodological issues and future research directions.

Digestate landspreading is a key aspect of the circular economy. However, organic matter (OM) stability in digestates is usually either poorly assessed or done through laborious methods. Spectroscopic methods are useful and easy to deploy alternatives to assess several aspects in anaerobic digestion (AD) studies such as process performance, waste classification and both OM composition and transformation. In these studies, a lack of agreement on analytical techniques, indicators and reference values is evident. This unclear scenario brings to the forefront the need for a meta-analytical study providing benchmarking values and trends. This review aimed to fill up this gap through the identification and evaluation of: (i) the most frequently applied techniques, their principles, deployment methods and limitations, (ii) the quantitative spectroscopic indices to define OM stability, (iii) the common trends of these parameters due to AD effect on the OM and (iv) the relevance of each technique based on the frequency of statistically significant results reported. Ultraviolet–visible and fluorescence spectroscopy have been identified as the most relevant techniques for aqueous phase study whereas mid-infrared and ¹³C cross-polarisation magic angle spinning nuclear magnetic resonance were the most appropriate for the solid phase. Their most applied indicators and their trends after AD have been summarised. Finally, the research studies that displayed statistically significant findings were described, the representativeness of the indices and the influence of sample preparation on their calculation were discussed and future research lines were suggested. Overall, this review demonstrates that spectroscopic methods provide relevant information for better digestate management.

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Manganese is extensively used in various advanced technologies. Due to high manganese demand and scarcity of primary manganese resources, extracting the metal from spent batteries is gaining increasing interest. The recycling of spent batteries for their critical metal content, is therefore environmentally and economically feasible. The conventional pyro- and hydrometallurgical extraction methods are energy-intensive or use hazardous chemicals. Bioleaching of manganese from spent batteries as secondary resource has been suggested to meet two objectives: reduce environmental footprint and turn waste into wealth. A bioleaching process can operate with less operating costs and consumption of energy and water, along with a simple process, which produces a reduced amount of hazardous by-products. Hence, this review discusses various approaches for bioleaching manganese from secondary resources using redoxolysis, acidolysis, and complexolysis. Candidate microbes for producing inorganic and organic biolixiviants are reviewed, along with the role of siderophores and extracellular polymeric substances as other effective agents in manganese extraction. The three main types of bioleaching are discussed, incorporating effective parameters with regard to temperature, pH, and pulp density, and future perspectives for manganese bioleaching and provided.

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In the past few decades, pollution from microplastics has emerged as an important issue on a global scale. These plastic particles are mainly the result of anthropogenic activities. Urban sprawl, industrialization, indiscriminate use and poor waste management of plastic products are the main factors responsible for the accumulation of microplastics in different ecosystems of the environment. The presence of microplastics in the soil matrix is considered an emerging threat to agroecosystems. Since most of the studies on microplastics have been done in the aquatic environment. The understanding of the ecotoxicological effects of these contaminants in terrestrial ecosystems is still limited, especially in agroecosystems. The negative effects of microplastics on the physical, chemical and biological properties of soil are now revealing. But the effects of microplastics on plant growth and yield are largely unexplored. Microplastic contamination in the soil can alter the functioning of plants by affecting the microbial community of the rhizosphere and disturbing the homeostasis of the agroecosystem. Furthermore, it may transfer into the plant system through nutrient and water absorption channels and affect plant physiology. The pervasive nature of microplastics in the soil is considered a barrier to sustainable agriculture and ecosystem functioning. The present review gives an overview of the sources, dissipation and effects of microplastics with reference to the soil–plant system, highlights the research gaps, and deciphers the possible future threats to agroecosystems.

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Constructed wetlands (CWs) are ecosystems artificially designed to mimic natural wetland systems for the treatment of effluents. Its adoption can be given both at a decentralized level and as an economic alternative for a variety of pollution controls: agricultural, industrial, mines and urban drainage effluents. Although a CW has larger area requirements than conventional energy-intensive treatment technologies, they have several advantages: lower costs; energy savings; fewer operating and maintenance requirements; enable wild habitat and natural leisure areas; and allow the use of solar energy. Thus, the treatment of effluents through CWs is highly promising. This review aims to encompass the current literature and state-of-the-art on CWs applied on domestic wastewater in decentralized systems, explaining with visual examples their constructions, processes and modalities.

One of agriculture’s most important goals is finding the proper equilibrium between sustainability and intensification of production. The exponential growth of the world population, climate variability, and soil degradation are essential factors that require the development of novel agricultural practices to achieve food security. In this context, organo-mineral fertilization has been proposed as a promising approach. Such a concept is based on novel fertilizers formulations combining organic and mineral resources features, which could simultaneously address soil fertility and health issues. The manufacturing processes of organo-mineral fertilizers (OMF) are highly versatile and revolve around the co-processing of organic and mineral matrices. OMF’s peculiarity resides in using systemic methodologies for waste valorization to generate cost-effective and eco-friendly products in alignment with the bio-circular economy. Despite their advantages, OMF adoption by farmers is still not satisfactory, which could be attributed to the difficulty of accessibility and a stagnant market. This work critically reviews recent advances in the organo-mineral fertilization concept. Our review provides an in-depth understanding of the chemical, biological, and thermal methodologies used for OMF generation through mineral and organic matrices co-processing. We also discuss the positive effect of such products on the plant-soil system by focusing on the mechanism of action. Furthermore, this review scrutinizes the innovation profile of OMF based on trends of patent submission during the last 20 years. It also provides future research and development pathways based on current drawbacks and limitations of the industry.

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The development of alternative, sustainable sources of fuels is necessary for addressing the increasing world’s energy demand and global warming crisis. Butanol, an important and promising biofuel candidate, is generally produced from heterotrophic microorganisms by carbohydrate fermentation. Cyanobacteria can serve as an alternative feedstock for third and fourth-generation biofuel production. Biofuel and biochemical synthesis from CO₂ using photosynthetic organisms is an attractive approach. These prokaryotic photosynthetic microorganisms have been used as an energy feedstock and also genetically engineered for direct conversion of CO₂ into butanol. This review aims to highlight the crucial aspects of photosynthetic biobutanol synthesis. The review explores the recent advances in biobutanol production from cyanobacteria. It reviews the recent and classical cyanobacterial genetic modification approaches and the advances in synthetic biology toolboxes of cyanobacteria. It discusses both third and fourth-generation butanol synthesis while emphasizes more on genetic modifications used in metabolic engineering and their effects on butanol production. Challenges associated with strain development, cultivation, butanol toxicity, and recovery have also been discussed.

BiOX (bismuth oxyhalides) are a ternary structure (V–VI–VII) of semiconductor materials with tunable band gaps, a low recombination rate, wide light absorption range, electro-magnetical and optical properties due to their unique crystallinity with tetragonal matlockite configuration. This article critically reviews the applicability of BiOX-based photocatalysts for water treatment and/or energy storage applications. To enhance their photocatalytic activities under visible light, a particular focus is given to the formation of heterojunctions, or plasmonic nanoparticles. Their technological strengths and limitations are evaluated and compared. Synthesis techniques such as precipitation, solvothermal, hydrolysis, and doping strategy of self-assembling BiOX including heterojunctions with other semiconductors in enhancing photocatalytic performance are presented. Research direction, challenges, and perspectives of BiOX-based photocatalysts for practical applications are elaborated. It is evident from a literature survey of 227 published articles (1972–2022) that the physico-chemical properties of BiOX-based photocatalysts such as energy band structures and anisotropic layered structure are responsible for UV light-driven photocatalytic performance. The hybridized valence band of O 2p and Bi 6s² orbitals in the Bi(III)-based compounds upshifts their valence band (v_b) that narrows energy bandgap and expands the absorption of visible light range. Among the BiOX, BiOI and BiOCl are the most outstanding photocatalysts under UV Vis irradiation due to their narrow bandgaps (E^o = 2.0 and 3.4 eV, respectively), large surface area, and strong light absorption. It is important to note that technical applicability, target pollutants, and cost-effectiveness represent the key factors in selecting the most appropriate BiOX-based photocatalysts for water treatment and/or energy storage applications.

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Amino acids (AAs) are important intermediate metabolites during the anaerobic digestion (AD) of protein-rich organic matter. L (levorotatory, left-handed) AAs are the predominant AAs found in proteolysis process, and can be converted to D (dextrorotatory, right-handed)-AAs. Alkaline, heat pretreatment and fermentation of the organic matter may lead to the transformation of AAs configuration, that is, L-AAs and D-AAs co-exist in the AD system. D-Ala, D-Asp, and D-Glu are the most frequently detected in food waste. D-AAs also widely exist in seeds, leaves and the extracellular biomolecules of bacterial cell walls and can be applied in pharmaceutical industry and agrochemical industry. Compared with L-AAs, D-AAs is not easily decomposed by microorganisms, thus D-AAs accumulate in waste/wastewater or natural environments. Many evidences showed that D-AAs have specific biological functions. AAs and their enantiomers have certain biological characteristics which are closely related to their configuration, which will have different effects on the microorganisms in the anaerobic system, and eventually affect the stability of AD and the yield of biogas. Therefore, this paper mainly reviews the distribution of AAs and enantiomeric function in AD system, analyzes the promoting/inhibitory effect of AAs on AD and the mechanisms, and puts forward some suggestions for future studies of AD of organic matter.

The Membrane bioreactor (MBR) technology enhances biomass retention with less residual sludge which is desirable for the treatment of strong wastewater such as landfill leachate. The technology has evolved to encompass anaerobic MBRs (AnMBRs) due to the benefit of producing renewable energy in the form of methane biogas and reducing the cost of aeration and sludge handling. This paper presents a critical review on the progress and application of the AnMBR technology for the treatment of landfill leachate in particular. We evaluate its performance and elaborate on potential operational limitations with emphasis on fouling and inhibitory factors that may suppress the development of microbial communities in AnMBR systems. We conclude by highlighting existing gaps and future directions and proposing a framework with a comprehensive experimental program towards improving the application of the AnMBR technology.