Reviews in Environmental Science and Bio/Technology最新文献

Bisphenol A (BPA) has been extensively applied for the production of polycarbonate plastics and epoxy resins, which has gained increasing attention due to its ubiquitous presence and adverse effect on ecosystems and human health. Various biological strategies (such as BPA biodegradation by bacteria, fungi, algae, and plants) have been developed to address BPA contamination issue. This review systematically summarized and analyzed recent advances in biological methods for BPA degradation, including bacterial, fungal, algal, and plants, highlighting the efficiency and mechanisms of BPA degradation. By analyzing the common intermediates of BPA biodegradation by bacteria, fungi, algae and plants reported in previous studies, the typical biodegradation pathways were proposed. The review further addressed the contentious topic of anaerobic BPA degradation, noting the scarcity of definitive evidence endorsing this process. Further, the common enzymes and typical enzymatic reactions involved in the biodegradation process of BPA were summarized. This review will deepen the understanding of BPA biodegradation, leading to the discovery of more efficient microorganisms and highly effective enzymatic catalysts for remediating BPA contamination.

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In many countries, scientists have developed techniques and processing methods to minimize animal feed waste and costs. The agricultural waste from each part of the cassava plant is rich in macronutrients, essential amino acids, vitamins, and minerals, making it a potential candidate to be used as animal feed. However, the significant content of anti-nutritional properties in cassava, which are linked with the indigestibility of the animal, led to controversy regarding the strategy to use cassava as highly commercialized animal feed. Among the anti-nutritional compounds found in cassava waste, cyanide was found to have the most negative effect on the animals upon feed consumption. Therefore, several strategies to maintain the homeostasis of nutrient and non-nutrient compounds improved the production and commercialization of cassava waste-based animal feed. Physical pretreatment, microbial pretreatment, and fermentation significantly reduced the cyanide content in the cassava waste. In terms of fermentation, solid-state fermentation of moist, solid, non-soluble organic material acts as a nutrient and energy source. Factors such as moisture content, particle size, temperature, pH, media composition, choice of microbial inoculum, and inoculum density were important to increase protein content, improve digestibility, amino acids, enzymes, and vitamins. The impact of using cassava waste as animal feed replacement was significant on the digestibility, growth performance, and changes in blood parameters of the animals. Despite the challenges in nutrient content and biological action, the accessibility and availability of cassava in different geographical areas also pose significant challenges. Therefore, applying technological advancements, particularly in enhancing the nutritional content and biological mechanisms, is important, with the implementation of advanced research and collaboration with industries and other stakeholders.

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Biogas contains significant quantities of undesirable and toxic compounds, such as hydrogen sulfide (H₂S), posing severe concerns when used in energy production-related applications. Therefore, biogas needs to be upgraded by removing H₂S to increase their bioenergy application attractiveness and lower negative environmental impacts. Commercially available biogas upgradation processes can be expensive for small and medium-scale biogas production plants, such as wastewater treatment facilities via anaerobic digestion process. In addition, an all-inclusive review detailing a comparison of biochar and hydrochar for H₂S removal is currently unavailable. Therefore, the current study aimed to critically and systematically review the application of biochar/hydrochar for H₂S removal from biogas. To achieve this, the first part of the review critically discussed the production technologies and properties of biochar vs. hydrochar. In addition, exisiting technologies for H₂S removal and adsorption mechanisms, namely physical adsorption, reactive adsorption, and chemisorption, responsible for H₂S removal with char materials were discussed. Also, the factors, including feedstock type, activation strategies, reaction temperature, moisture content, and other process parameters that could influence the adsorption behaviour are critically summarised. Finally, synergy and trade-offs between char and biogas production sectors and the techno-economic feasibility of using char for the adsorption of H₂S are presented. Biochar’s excellent structural properties coupled with alkaline pH and high metal content, facilitate physisorption and chemisorption as pathways for H₂S removal. In the case of hydrochar, H₂S removal occurs mainly via chemisorption, which can be attributed to well-preserved surface functional groups. Challenges of using biochar/hydrochar as commercial adsorbents for H₂S removal from biogas stream were highlighted and perspectives for future research were provided.

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The mangrove ecosystem is a sensitive and highly productive ecosystem in the sea-land transition zone. Mangroves are almost saturated with marine ecosystems and provide ecological services and the organisms of the mangrove ecosystem are adapted to the dynamic conditions of the intertidal zone. For global sustainability, anthropogenic activities that destroy mangrove ecosystems must be reduced, and effective management is needed to mitigate these threats to improve mangrove health and ecosystem services. Plant growth-promoting microorganisms (PGPMs), which include growth-promoting bacteria (PGPB) such as Acinetobacter, Alcaligenes, Arthrobacter, Azospirillum, Azotobacter, Bacillus, Burkholderia, Clostridium, Enterobacter, Flavobacterium, Paenibacillus, Pseudomonas, and Rhizobium, plant growth promoting actinobacteria (PGPA) Actinophytocola, Nocardiopsis, Pseudonocardia, and Streptomyces, plant growth promoting fungi (PGPF) Aspergillus, Fusarium, Gliocladium, Humicola, Penicillium, Phoma, and Trichoderma and plant growth promoting cyanobacteria (PGPC) like Anabaena, Aphanothece, Calothrix, Lyngbya, Microcoleus, Nostoc, and Oscillatoria help the mangrove plants to acquire nutrients, produce growth-promoting substances, and resist stress. In addition, PGPMs promote nutrient cycling, leaf litter degradation, organic and inorganic pollutant remediation, pathogen inhibition, and enhance soil stabilization. The biofilm formed by PGPMs increases physical, chemical, and biological stress resistance, and the associated extracellular polymeric substances (EPS) stabilize the soil. This complex and highly structured microbial community is essential to plant and soil health. The primary goal of this review is to explore the ecological interactions between microbes, mangrove plants, and the intertidal environment, focusing on implementing PGPM-based strategies to sustain mangrove ecosystems. Additionally, this review explores how PGPMs enhance plant and soil health, mitigate stress in mangrove vegetation, and improve ecosystem services.

Plastics and other polymer-based compounds are inevitable in our day-to-day life starting from packaging to consumer goods. Awareness about recycling plastics is all known; however, it is not sufficient to contain their negative effects on the environment and health. Disintegration products of plastic called micro- and nano-plastics (M/NPs) are increasingly found in food and environmental samples, which are considered to be an invisible threat with greater impact. Yet, there are no comprehensive regulations to monitor the M/NPs in food and water samples. Considering their harmful effects, there is a need for appropriate detection techniques to effectively identify and quantify the M/NPs in food and environment. Conventional techniques such as the Fourier transform infrared spectroscopy, Raman spectroscopy and scanning electron microscopy are expensive, require lab and labor, and are not suitable for on-field real-time monitoring. Optical detection techniques using various probes and sensors have been extensively used in the fields of bioimaging, biosensing, molecular fingerprinting etc. Recent research suggests that these probes and sensors are effective in detecting and quantifying the M/NPs. In this regard, the distinctive features of visual, colorimetric and plasmonic detection techniques have proved their high-end applicability. Most of these detectors are based on the principles of fluorescence, localized surface plasmon resonance, colorimetry, surface-enhanced Raman spectroscopy and speckle pattern analysis. This review discusses the recent advancements in the field of optical detection for M/NPs, summarizing its advantages, salient features, drawbacks, and ideas for future research.

The current agri-food systems are unable to fulfill global demand and account for 33% of all greenhouse gas emissions. Conventional agriculture cannot produce more food because of the scarcity of arable land, the depletion of freshwater resources, and the increase in greenhouse gas emissions. Thus, it is important to investigate alternate farming methods. Algae farming is a feasible alternative that produces food, feed, and feedstock using wastelands and unconventional agricultural settings such as coastal regions, salt-affected soils, and urban/peri-urban environments. This review focuses on three emerging scenarios. First is seawater, which makes up 97.5% of the water on Earth. However, it is nevertheless used less often than freshwater. Second is a growing trend of people moving from rural to urban regions for improved employment prospects, living standards, and business chances. However, most rural migrants are essentially skilled in agriculture, which limits their applicability in metropolitan environments. The third scenario focuses on excellent crop yields and soil fertility; it is essential to maintain appropriate levels of organic matter and soil structure. In this case, algae have remarkable potential for osmoregulation-based salt tolerance and may provide valuable metabolites when cultivated in brackish or saltwater. Using brackish water, treated wastewater, and saltwater, algal culture systems may be established in arid/semi-arid, urban/peri-urban, and coastal areas to fulfill the increasing need for food, feed, and industrial feedstocks. It may also provide migrants from rural areas with work possibilities, which would allay environmental footprints.

Greenhouse gas emissions and climate change concerns have prompted worldwide initiatives to lower carbon dioxide (CO₂) levels and prevent them from rising in the atmosphere, thereby controlling global warming. Effective CO₂ management through carbon capture and storage is essential for safe and permanent storage, as well as synchronically meeting carbon reduction targets. Lowering CO₂ emissions through carbon utilization can develop a wide range of new businesses for energy security, material production, and sustainability. CO₂ mineralization is one of the most promising strategies for producing thermodynamically stable solid calcium or magnesium carbonates for long-term sequestration using simple chemical reactions. Current advancements in CO₂ mineralization technologies,focusing on pathways and mechanisms using different industrial solid wastes, including natural minerals as feedstocks, are briefly discussed. However, the operating costs, energy consumption, reaction rates, and material management are major barriers to the application of these technologies in CO₂ mineralization. The optimization of operating parameters, tailor-made equipment, and smooth supply of waste feedstocks require more attention to make the carbon mineralization process economically and commercially viable. Here, carbonation mechanisms, technological options to expedite mineral carbonation, environmental impacts, and prospects of CO₂ mineralization technologies are critically evaluated to suggest a pathway for mitigating climate change in the future. The integration of industrial wastes and brine with the CO₂ mineralization process can unlock its potential for the development of novel chemical pathways for the synthesis of calcium or magnesium carbonates, valuable metal recovery, and contribution to sustainability goals while reducing the impact of global warming.

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As an essential strategy for transitioning towards a circular economy for a sustainable society, food waste (FW) can be efficiently used for the biological production of added-value compounds such as medium chain fatty acids (MCFAs). The microbial conversion of FW into MCFAs is an ecofriendly, sustainable and cost-effective approach that reduces the great pressure on land and water resources associated with traditional MCFAs production methods. Among the MCFAs, caproate holds high economic value and a large market size due to its widespread application in several industrial areas. The biological production of caproate from FW is a complex mechanism that requires a deep understanding of microbial dynamics, metabolic potentialities and functional stability for process optimization and large-scale application. This review aims to outline the existing knowledge about bacterial component involved in the caproate production from FW. Innovative approaches to address current research gaps, ensuring a thorough and up-to-date understanding of the biological caproate production are herein identified and proposed.

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Incineration is an integral part of the waste management process to reduce the enormous volumes of municipal solid waste generated daily. Of the various incineration products, bottom ash makes up a major portion, which subsequently needs to be disposed or reused. Unavoidably, trace amounts of heavy metal content present in incineration bottom ash (IBA) can be leached out over time, ending up in water bodies and eventually entering the food chain. This can lead to toxic bioaccumulation of heavy metals in animals and humans. To minimize leaching, it is essential for heavy metals in IBA to be effectively immobilized. In this review, we critically evaluate the effectiveness of various heavy metal immobilization strategies to treat IBA in terms of their suppression of heavy metal leaching based on past research examples. Furthermore, these strategies are assessed for their medium to long term stabilities, potential impact on the environment, as well as challenges that may be faced in their successful implementation. Finally, some future directions in heavy metal immobilization efforts are proposed in light of the present climate crisis.

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Water hyacinth (Pontederia crassipes) is a free-floating macrophyte and an abundantly available species of aquatic weeds worldwide. This species is widely dispersed among rivers, lakes, and other water bodies. Exceptional proliferation rate, ability to adapt to a varied range of ecosystems, and aggressive growth are its prominent features. These characteristics pose a serious threat to surface water bodies by restricting light and air transfer rates. As a result, runoff, navigation, and fishing in the waterbodies are hindered. In addition, the growth of water hyacinths in waterbodies provides a suitable ecosystem for the propagation of pests and insects, which spreads diseases, subsequently reduces the water quality, and diminishes the useful flora and fauna of the waterbodies. Different physical, chemical, and biological control measures have been employed so far to eradicate these weeds and have partly alleviated the problems. However, the approaches of transforming water hyacinths into useful resources such as agricultural products, e.g., compost, biofertilizer, and mulch, energy resources such as bioethanol, biomethane, biohydrogen, and biochar, and other resources such as biopolymers, animal feed and fish feed, and high-value chemicals have been gaining popularity in the last decade. These are the sustainable approaches to manage this issue. Furthermore, water hyacinth has potential applications in phytoremediation, including removing toxic, heavy metals, and inorganic and organic pollutants. Here, our goal is to characterize the morphology of water hyacinth biomass and evaluate its potential for environmental and bioenergy-based applications. Additionally, an in-depth discussion on the potential of water hyacinths to produce promising socioeconomic impacts by nurturing communities and empowering downtrodden people is also highlighted here.