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As the demand for tea (Camellia sinensis) has grown across the world, the amount of biomass waste that has been produced during the harvesting process has also increased. Tea consumption was estimated at about 6.3 million tonnes in 2020 and is anticipated to reach 7.4 million tonnes by 2025. The generation of tea waste (TW) after use has also increased concurrently with rising tea consumption. TW includes clipped stems, wasted tea leaves, and buds. Many TW-derived products have proven benefits in various applications, including energy generation, energy storage, wastewater treatment, and pharmaceuticals. TW is widely used in environmental and energy-related applications. Energy recovery from low- and medium-calorific value fuels may be accomplished in a highly efficient manner using pyrolysis, anaerobic digestion, and gasification. TW-made biochar and activated carbon are also promising adsorbents for use in environmental applications. Another area where TW shows promise is in the synthesis of phytochemicals. This review offers an overview of the conversion procedures for TW into value-added products. Further, the improvements in their applications for energy generation, energy storage, removal of different contaminants, and extraction of phytochemicals have been reviewed. A comprehensive assessment of the sustainable use of TWs as environmentally acceptable renewable resources is compiled in this review.
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Chá , ResíduosRESUMO
Bioactive polysaccharides and oligosaccharides were successfully extracted from three distinct seaweeds: Sargassum sp., Graciallaria sp., and Ulva sp. utilizing various extraction techniques. The obtained polysaccharides and oligosaccharides were subjected to comprehensive characterization, and their potential antioxidant properties were assessed using a Hep G2 cell model. Analysis via FTIR spectroscopy unveiled the presence of sulfate groups in the polysaccharides and oligosaccharides derived from Sargassum sp. The antioxidant capabilities were assessed through various assays (DPPH, ABTS, Fe-ion chelation, and reducing power), revealing that SAR-OSC exhibited superior antioxidant activity than others. This was attributed to its higher phenolic content (24.6 µg/mg), FRAP value (36 µM Vitamin C/g of extract), and relatively low molecular weight (5.17 kDa). The study also investigated the protective effects of these polysaccharides and oligosaccharides against oxidative stress-induced damage in Hep G2 cells by measuring ROS production and intracellular antioxidant enzyme expressions (SOD, GPx, and CAT). Remarkably, SAR-OSC demonstrated the highest efficacy in protecting Hep G2 cells reducing ROS production and downregulating SOD, GPx, and CAT expressions. Current findings have confirmed that the oligosaccharides extracted by the chemical method show higher antioxidant activity, particularly SAR-OSC, and robust protective abilities in the Hep G2 cells.
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A systematic evaluation of microorganism's potential towards biosynthesis of cellulases from inexpensive lignocellulosic feedstock through appropriate kinetic modelling facilitates understanding, optimization and designing of an effective industrial cellulase enzyme production process. The present study aims to optimize a submerged fungal cultivation strategy for cellulase production from abundantly available newspaper wastes (NPW). A combined pretreatment strategy consisting diluted, 1% (v v-1) H2SO4 followed by 2% (w v-1) NaOH treatment was highly effective to convert newspaper waste to an effective cellulose-enriched inducer for the production of cellulase. In addition, the composition of the most influential nutrient components like peptone and lactose was optimized with the help of response surface methodology for enhanced cellulase production with maximum activity levels. Maximum cellulase production of 8.64 g L-1 with 7.82 FPU mL-1 total activity levels was achieved from optimized composition of pretreated NPW 3.29% (w v-1), lactose 2.94% (w v-1) and peptone 1.53% (w v-1). To analyse intrinsic inhibition effect of the substrate concentration on cellulase production, modified Luedeking-Piret model simulated experiments were further conducted with 1.5% (w/v), 3.29% (w/v) and 4% (w/v) NPW concentrations. The developed kinetic model perfectly captured the trends of biomass production, substrate consumption and adsorption characteristic of cellulase enzyme on its activity during production. The rate constant for cellulase synthesis was evaluated to be increased to 0.040 IU g-1 h -1 at 3.29% (w v-1) of NPW concentration; however, it was further reduced to 0.024 IU g-1 h -1 at higher NPW concentration of 4% (w v-1).
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Celulase , Celulases , Biomassa , Celulase/química , Fermentação , Lactose , PeptonasRESUMO
Gellan gum (GG) - the microbial exopolysaccharide is increasingly being adopted into drug development, tissue engineering, and food and pharmaceutical products. In spite of the commercial importance and expanding application horizon of GG, little attention has been directed toward the exploration of novel microbial cultures, development of advanced screening protocols, strain engineering, and robust upstream or downstream processes. This comprehensive review not only attempts to summarize the existing knowledge pool on GG bioprocess but also critically assesses their inherent challenges. The process optimization design augmented with advanced machine learning modeling tools, widely adopted in other microbial bioprocesses, should be extended to GG. The unification of mechanistic insight into data-driven modeling would help to formulate optimal feeding and process control strategies.
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Polissacarídeos Bacterianos , Polissacarídeos Bacterianos/química , Aprendizado de Máquina , FermentaçãoRESUMO
Advancements in research concerning the occurrence of microplastics (MPs) in human blood, sputum, urine, and breast milk samples have piqued the interest of the scientific community, prompting further investigation. MPs present in the placenta, amniotic fluid, and meconium raise concerns about interference with embryonic development, leading to preeclampsia, stillbirth, preterm birth, and spontaneous abortion. The challenges posed by MPs extend beyond pregnancy, affecting the digestive, reproductive, circulatory, immune, and central nervous systems. This has spurred scientists to examine the origins of MPs in distinct environmental layers, including air, water, and soil. These risks continue after birth, as neonates are continuously exposed to MPs through everyday items such as breast milk, cow milk and infant milk powder, as well as plastic-based products like feeding bottles and breast milk storage bags. It is the need of the hour to strike a balance amidst lifestyle changes, alternative choices to traditional plastic products, raising awareness about plastic-related health risks, and fostering collaboration between the scientific community and policymakers. This review aims to provide fresh insights into potential sources of MP pollution, with a specific focus on pregnancy and neonates. It is the first compilation of its kind so far that includes critical studies on recently reported discoveries.
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Líquidos Corporais , Nascimento Prematuro , Poluentes Químicos da Água , Recém-Nascido , Feminino , Gravidez , Animais , Bovinos , Lactente , Humanos , Microplásticos , Plásticos , Leite Humano , Monitoramento AmbientalRESUMO
Microplastics (MPs) are plastic particles in a size ranging from 1 mm to 5 mm in diameter, and are formed by the breakdown of plastics from different sources. They are emerging environmental pollutants, and pose a great threat to living organisms. Improper disposal, inadequate recycling, and excessive use of plastic led to the accumulation of MP in the environment. The degradation of MP can be done either biotically or abiotically. In view of that, this article discusses the molecular mechanisms that involve bacteria, fungi, and enzymes to degrade the MP polymers as the primary objective. As per as abiotic degradation is concerned, two different modes of MP degradation were discussed in order to justify the effectiveness of biotic degradation. Finally, this review is concluded with the challenges and future perspectives of MP biodegradation based on the existing research gaps. The main objective of this article is to provide the readers with clear insight, and ideas about the recent advancements in MP biodegradation.
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Poluentes Ambientais , Poluentes Químicos da Água , Microplásticos , Plásticos , Polímeros , Biodegradação AmbientalRESUMO
Reducing sugar generation from lignocellulosic biomass (LCB) is closely linked with biomass characteristics, pretreatment and enzymatic hydrolysis conditions. In this study curated experimental data from literature was used to develop multivariate regression and artificial neural network (ANN) model considering nine predictors (i.e., cellulose, hemicellulose, lignin content, cellulose-lignin ratio, acid concentration, temperature, time, pretreatment severity, and enzyme concentration). Selected reduced polynomial model (R2: 0.891, Adj. R2: 0.849) suggests positive influence of acid and enzyme, while negative influence of treatment severity, temperature and time on reducing sugar generation. Genetic algorithm-optimized ANN model offered excellent fitness for LCB hydrolysis on training (R2: 0.997), validation (R2: 0.984), and test sets (R2: 0.967). Sensitivity analysis of the ANN predictors suggests lignin and to some extent hemicellulose contents can be inhibitory. Though polynomial models can have simple interpretation, use of optimized ANN offers better predictability in dataset with diverse biomass compositions.
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Celulase , Lignina , Açúcares , Biomassa , Hidrólise , Carboidratos , Celulose , Redes Neurais de ComputaçãoRESUMO
The application of on-site produced cellulolytic enzymes in place of commercial enzymes towards hydrolytic preparations of reducing sugars using inexpensive lignocellulosic wastes is considered the most efficient strategy to accomplish a cost-effective biofuel production process. Along with improved production, intrinsic and systematic performance evaluation of the produced enzyme during the hydrolysis process through kinetic intervention remains a crucial requirement for achieving the improved performance of the process. With this motivation, the present study primarily deals with the nutritionally optimized production strategy of cellulases from rice straw (RS) waste using Trichoderma reesei (MTCC 164). The highest cellulase production was obtained 8.09 ± 0.32 g/l in batch mode at optimized combinations of 3.5% (w/v) RS inducer, 3.0% (w/v) lactose, and 1.5% (w/v) peptone. Production was further improved through pH-regulated (pH 5.5 to 6.5) fed-batch fermentations. The enzyme produced at pH 6 was considered for hydrolysis studies at 4 to 10% (w/w) solid loading due to reasonable exoglucanase, endoglucanase, and maximum ß-glucosidase activity levels of 9.3 U/ml, 3.87 U/ml, and 2.65 U/ml respectively. Multi-reaction systematic kinetic modeling was implemented to evaluate enzyme performance during hydrolysis, and the values of inhibitory kinetic parameters (K2r = 7.1 < K1r = 18.5 < K3r = 276.6) suggested that sequential conversion of cellulose to glucose by existing enzyme components was more dominant over direct conversion.
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Celulase , Celulases , Oryza , Oryza/metabolismo , Hidrólise , Celulose/metabolismo , FermentaçãoRESUMO
In the recent past, an increasing interest is mostly observed in using microwave and ultrasonic irradiation to aid the biological conversion of waste materials into value-added products. This study is focused on various individual impacts of microwaves and ultrasonic waves for the treatment of biomass before the synthesis of value-added products. Following, a comprehensive review of the mechanisms governing microwaves and ultrasonication as the treatment methods, their effects on biomass disruption, solubilization of organic matter, modification of the crystalline structure, enzymatic hydrolysis and production of reducing sugars was performed. However, based on the lab-scale experiments evaluated, microwaves and ultrasonication were studied to be economically and energetically ineffective despite their beneficial effects on the waste biomass. This article reviews some of the difficulties associated with using microwaves and ultrasonic irradiation for the efficient processing of waste biomasses and identified some potential directions for future study.
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Lignina , Micro-Ondas , Lignina/química , Biomassa , Hidrólise , ResíduosRESUMO
Rapidly changing bioremediation prospects are key drive to develop sustainable options that can offer extra benefits rather than only environmental remediation. Algal remediating is gaining utmost attention due to its mesmerising sustainable features, removing odour and toxicity, co-remediating numerous common and emerging inorganic and organic pollutants from gaseous and aqueous environments, and yielding biomass for a range of valuable products refining. Moreover, it also improves carbon footprint via carbon-capturing offers a better option than any other non-algal process for several high CO2-emitting industries. Bio-uptake, bioadsorption, photodegradation, and biodegradation are the main mechanisms to remediate a range of common and emerging pollutants by various algae species. Bioadsorption was a dominant remediation mechanism among others implicating surface properties of pollutants and algal cell walls. Photodegradable pollutants were photodegraded by microalgae by adsorbing photons on the surface and intracellularly via stepwise photodissociation and breakdown. Biodegradation involves the transportation of selective pollutants intracellularly, and enzymes help to convert them into simpler non-toxic forms. Robust models are from the green microalgae group and are dominated by Chlorella species. This article compiles the advancements in microalgae-assisted pollutants remediation and value-addition under sustainable biorefinery prospects. Moreover, filling the knowledge gaps, and recommendations for developing an effective platform for emerging pollutants remediation and realization of commercial-scale algal bioremediation.
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Chlorella , Poluentes Ambientais , Recuperação e Remediação Ambiental , Microalgas , Biodegradação Ambiental , BiomassaRESUMO
In the continual march to a predominantly urbanized civilization, anthropogenic activities have increased scrupulously, industrialization have occurred, economic growth has increased, and natural resources are being exploited, causing huge waste management problems, disposal issues, and the evolution of several pollutants. In order to have a sustainable environment, these pollutants need to be removed and degraded. Bioremediation employing microorganisms or enzymes can be used to treat the pollutants by degrading and/or transforming the pollutants into different form which is less or non-toxic to the environment. Laccase is a diverse enzyme/biocatalyst belonging to the oxidoreductase group of enzymes produced by microorganisms. Due to its low substrate specificity and monoelectronic oxidation of substrates in a wide range of complexes, it is most commonly used to degrade chemical pollutants. For degradation of emerging pollutants, laccase can be efficiently employed; however, large-scale application needs reusability, thermostability, and operational stability which necessitated strategies like immobilization and engineering of robust laccase possessing desirable properties. Immobilization of laccase for bioremediation, and treatment of wastewater for degrading emerging pollutants have been focussed for sustainable development. Challenges of employing biocatalysts for these applications as well as engineering robust laccase have been highlighted in this study.
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Poluentes Ambientais , Lacase/química , Águas Residuárias , Eliminação de Resíduos Líquidos , Enzimas Imobilizadas/metabolismo , Biodegradação AmbientalRESUMO
Present study focused on optimizing bioprocess condition for microalgal lutein production. From previous baseline yields of biomass (3.46 g/L) and lutein (13.7 mg/g), this study examined few key parameters. The 3X:3X ratio macro- and micronutrients was the most affecting parameter with highest biomass and lutein yields of 4.61 g/L and 14.3 mg/g. Temperature 30 °C enhanced the lutein up to 17.3 mg/g but reduced the biomass to 3 g/L. The light effects study showed 10 k lux was most effective for lutein up to 14 mg/g, and effect of increasing salinity (25-75 %) was detrimental. All the above parameters' optimization resulted in a lipid content of 22.5-26.5 %. A maximum lutein productivity and yield of 0.451 mg/L/d and 65.74 mg/L with a 3X:3X macro- and micronutrient ratio was achieved. The Chlorella sorokiniana Kh12 strain exhibited one of the highest yields among recent reports; hence it could be a source for commercial lutein production.
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Chlorella , Microalgas , Luteína , Biomassa , TemperaturaRESUMO
This study addresses the pressing need for sustainable bioremediation solutions to combat increasing pollution challenges in alignment with sustainability development goals. The research focuses on developing a co-culture approach involving microalgae and Komagataeibacter europaeus BCRC 14148 bacterium to create a biocomposite for efficient ammonia removal. Nanocellulose, produced by the bacterium, serves as a substrate for microalgae attachment. Optimization using specific growth media ratios resulted in biocomposite yields of 4.05 ± 0.16 g/L and 3.83 ± 0.13 g/L in HS medium with fructose and glucose, respectively. The optimal conditions include a 40:60 ratio of HS-F to TAP medium, 25 â incubation, 6000 Lux light intensity, pH 5.5, and a 48-hour incubation period. When applied to wastewater treatment, the biocomposite demonstrated exceptional ammonium removal efficiency at 91.64 ± 1.27 %. This co-culture-derived biocomposite offers an eco-friendly, recyclable, and effective solution for sustainable environmental bioremediation.
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Celulose , Microalgas , Águas Residuárias , Amônia , Técnicas de Cocultura , BiomassaRESUMO
Advanced sustainable bioremediation is gaining importance with rising global pollution. This review examines microalgae's potential for sustainable bioremediation and process enhancement using multi-omics approaches. Recently, microalgae-bacterial consortia have emerged for synergistic nutrient removal, allowing complex metabolite exchanges. Advanced bioremediation requires effective consortium design or pure culture based on the treatment stage and specific roles. The strain potential must be screened using modern omics approaches aligning wastewater composition. The review highlights crucial research gaps in microalgal bioremediation. It discusses multi-omics advantages for understanding microalgal fitness concerning wastewater composition and facilitating the design of microalgal consortia based on bioremediation skills. Metagenomics enables strain identification, thereby monitoring microbial dynamics during the treatment process. Transcriptomics and metabolomics encourage the algal cell response toward nutrients and pollutants in wastewater. Multi-omics role is also summarized for product enhancement to make algal treatment sustainable and fit for sustainable development goals and growing circular bioeconomy scenario.
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Microalgas , Purificação da Água , Águas Residuárias , Biocombustíveis , Microalgas/metabolismo , Metagenômica , BiomassaRESUMO
The rising consumption of the popular non-alcoholic beverage tea and its derivative products caused massive growth in worldwide tea production in the last decade, leading to the generation of huge quantities of waste tea residues every year. Most of these wastes are usually burnt or disposed in landfills without proper treatment which results in serious environmental issues by polluting water, air and soil. In the recent times, 'waste to wealth' is a fast-growing concept for environment friendly sustainable development. Utilization of the large amount of tea wastes for the production of low-cost adsorbents to reduce the expenses of water and wastewater treatment can be a sustainable way of management of these wastes which at the same time will improve circular economy also. This review endeavours to evaluate the potential of both raw and modified tea wastes towards the adsorption of pollutants from wastewater. The production of various adsorptive materials such as biochar, activated carbon, nanocomposites, hydrogels, nanoparticles from tea wastes are summarized. The advancements in their applications for the removal of different emerging contaminants from wastewater as well as potable water, air and soil are exhaustively reviewed. The outcome of the present review reveals that tea waste and its derivatives are appropriate candidates to be used as adsorbents that show tremendous effectiveness in cleaning the environment. This article will provide the readers with an in-depth knowledge on the sustainable utilization of tea waste as adsorbent materials and will assist them to explore this abundant cheap waste biomass for environmental remediation.
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Recuperação e Remediação Ambiental , Poluentes Químicos da Água , Adsorção , Solo , Chá/química , Águas Residuárias , ÁguaRESUMO
Practically, high-yield conversion of biomass into value-added products at low cost is a primary goal for any lignocellulosic refinery. In the industrial context, the limitation in the practical adaptation of the conventional techniques practically involves multiple reactors for the conversion of biomass to bioproducts. Therefore, the present manuscript critically reviewed the advancements in one-pot reaction systems with a major focus on the scientific production of value-added products from lignocellulosic biomass. In view of that, the novelty of one-pot reactions is shown during the fractionation of biomass into their individual constituents. The importance of the direct conversion of cellulose and lignin into a range of valuable products including organic acids and platform chemicals are separately discussed. Finally, the article is concluded with the opportunities, existing troubles, and possible solutions to overcome the challenges in lignocellulosic biorefinery. This article will assist the readers to identify the economic-friendly-one-pot conversion of lignocellulosic biomass.
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Celulose , Lignina , Biomassa , Compostos Orgânicos , BiocombustíveisRESUMO
Over the last few decades, the globe has much relied on fossil fuels; however, environmental concerns forced the World to look at biofuel as an alternative for stable economic development. Biofuel also facilitates national energy security maintenance and reduces environmental complications. The present study is focused on an in-depth analysis of bioenergy policy measures undertaken by various federal agencies of different countries in order to shed light on the bottlenecks that impede biofuel's growth as a sustainable and alternative fuel. An in-depth assessment of feedstock utilization, blending targets, and policy assistance schemes have been thoroughly reviewed. In addition, the potential of commercial firms for the production of bioenergy is highlighted in order to grasp the current bioenergy market scenario better. Finally, the article is concluded with the viewpoints of the authors to address the standing issues of global bioenergy generation.
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Biocombustíveis , Desenvolvimento Sustentável , Biomassa , Combustíveis FósseisRESUMO
Bacterial cellulose (BC) represents a novel bio-origin nonomaterial with its unique properties having diverse applications. Increased market demand and low yield are the major reason for its higher cost. Bacteria belonging to Komagataeibacter sp are the most exploited ones for BC production. Development of a cost-effective bioprocess for higher BC production is desirable. Though static fermentation modes have been majorly employed for BC production using tray fermenters, agitated mode has also been employed successfully with air-lift fermenters as well as stirred tank reactors. Bioprocess advances in recent years has led BC production to an upper level; however, challenges of aeration requirement and labor cost towards the higher end is associated with static cultivation at large scale. We have discussed the bioprocess development for BC production in recent years along with the challenges associated and the path forward.
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Bactérias , Celulose , Bactérias/metabolismo , Celulose/metabolismo , FermentaçãoRESUMO
There is an immediate global requirement for an ingenious strategy for food waste conversion to biofuels in order to replace fossil fuels with renewable resources. Food waste conversion to bioethanol could lead to a sustainable process having the dual advantage of resolving the issue of food waste disposal as well as meeting the energy requirements of the increasing population. Food waste is increasing at the rate of 1.3 billion tonnes per year, considered to be one-third of global food production. According to LCA studies discarding these wastes is detritus to the environment, therefore; it is beneficial to convert the food waste into bioethanol. The CO2 emission in this process offers zero impact on the environment as it is biogenic. Among several pretreatment strategies, hydrothermal pretreatment could be a better approach for pretreating food waste because it solubilizes organic solids, resulting in an increased recovery of fermentable sugars to produce bioenergy.
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Eliminação de Resíduos , Biocombustíveis , Biomassa , Fermentação , Alimentos , Eliminação de Resíduos/métodos , AçúcaresRESUMO
Strategic valorization of readily available sugarcane bagasse (SB) is very important for waste management and sustainable biorefinery. Conventional SB pretreatment methods are ineffective to meet the requirement for industrial adaptation. Several past studies have highlighted different pretreatment procedures which are lacking environmentally benign characteristics and effective SB bioconversion. This article provides an in-depth review of a variety of environmentally acceptable thermochemical and biological pretreatment techniques for SB. Advancements in the conversion processes such as pyrolysis, liquefaction, gasification, cogeneration, lignin conversion, and cellulose conversion via fermentation processes are critically reviewed for the formation of an extensive array of industrially relevant products such as biofuels, bioelectricity, bioplastics, bio adsorbents, and organic acids. This article would provide comprehensive insights into several crucial aspects of thermochemical and biological conversion processes, including systematic perceptions and scientific developments for value-added products from SB valorization. Moreover, it would lead to determining efficient pretreatment and/or conversion processes for sustainable development of industrial-scale sugarcane-based biorefinery.