Aquatic weeds pose hazards to aquatic ecosystems and particularly the aquatic environment in shellfish aquaculture due to its excessive growth covering entire freshwater bodies, leading to environmental pollution particularly eutrophication intensification, water quality depletion and aquatic organism fatality. In this study, pyrolysis of six aquatic weed types (wild and cultured species of Salvinia sp., Lemna sp. and Spirodella sp.) were investigated to evaluate its potential to reduce and convert the weeds into value-added chemicals. The aquatic weeds demonstrated high fixed carbon (8.7-47.3 wt%), volatile matter content (39.0-76.9 wt%), H/C ratio (1.5-2.0) and higher heating value (6.6-18.8 MJ/kg), representing desirable physicochemical properties for conversion into biofuels. Kinetic analysis via Coats-Redfern integral method obtained different orders for chemical reaction mechanisms (n = 1, 1.5, 2, 3), activation energy (55.94-209.41 kJ/mol) and pre-exponential factor (4.08 × 104-4.20 × 1017 s-1) at different reaction zones (zone 1: 150-268 °C, zone 2: 268-409 °C, zone 3: 409-600 °C). The results provide useful information for design and optimization of the pyrolysis reactor and establishment of the process condition to dispose this environmentally harmful species.
Organophosphorus (OP) compounds are one of the most hazardous chemicals used as insecticides/pesticide in agricultural practices. A large variety of OP compounds are hydrolyzed by organophosphorus hydrolases (OPH; EC 3.1.8.1). Therefore, OPHs are among the most suitable candidates which could be used in designing enzyme-based sensors for detecting OP compounds. In the present work, a novel nanobiosensor for the detection of paraoxon was designed and fabricated. More specifically, OPH was covalently embedded onto chitosan and the enzyme-chitosan bioconjugate was then immobilized on negatively charged gold nanoparticles (AuNPs) electrostatically. The enzyme was immobilized on AuNPs without chitosan as well to compare the two systems in terms of detection limit and enzyme stability under different pH and temperature conditions. Coumarin 1, a competitive inhibitor of the enzyme, was used as a fluorogenic probe. The emission of coumarin 1 was effectively quenched by the immobilized Au-NPs when bound to the developed nanobioconjugates. However, in the presence of paraoxon, coumarin 1 left the nanobioconjugate leading to enhanced fluorescence intensity. Moreover, compared to the immobilized enzyme without chitosan, the chitosan-immobilized enzyme was found to possess decreased Km value by over 50%, increased Vmax and Kcat values by around 15% and 74%, respectively. Higher stability within a wider range of pH (2-12) and temperature (25-90°C) was also achieved. The method worked in the 0 to 1050 nM concentration ranges, and had a detection limit as low as 5 × 10(-11) M.
Biotechnology-based detection systems and sensors are in use for a wide range of applications in biomedicine, including the diagnostics of viral pathogens. In this review, emerging detection systems and their applicability for diagnostics of viruses, exemplified by the case of avian influenza virus, are discussed. In particular, nano-diagnostic assays presently under development or available as prototype and their potentials for sensitive and rapid virus detection are highlighted.
Global production of shellfish aquaculture is steadily increasing owing to the growing market demands for shellfish. The intensification of shellfish aquaculture to maximize production rate has led to increased generation of aquaculture waste streams, particularly the effluents and shellfish wastes. If not effectively managed, these wastes could pose serious threats to human health and the ecosystem while compromising the overall sustainability of the industry. The present work comprehensively reviews the source, composition, and environmental implications of shellfish wastes and aquaculture wastewater. Moreover, recent advancements in the valorization of shellfish wastes into value-added biochar via emerging thermochemical and modification techniques are scrutinized. The utilization of the produced biochar in removing emerging pollutants from aquaculture wastewater is also discussed. It was revealed that shellfish waste-derived biochar exhibits relatively higher adsorption capacities (300-1500 mg/g) compared to lignocellulose biochar (<200 mg/g). The shellfish waste-derived biochar can be effectively employed for the removal of various contaminants such as antibiotics, heavy metals, and excessive nutrients from aquaculture wastewater. Finally, future research priorities and challenges faced to improve the sustainability of the shellfish aquaculture industry to effectively support global food security are elaborated. This review envisages that future studies should focus on the biorefinery concept to extract more useful compounds (e.g., carotenoid, chitin) from shellfish wastes for promoting environmental-friendly aquaculture.
Anaerobic digestion (AD) of organic wastes is among the most promising approaches used for the simultaneous treatment of various waste streams, environment conservation, and renewable bioenergy generation (biomethane). Among the latest innovations investigated to enhance the overall performance of this process both qualitatively and quantitatively, the application of some nanoparticles (NPs) has attracted a great deal of attention. Typically, the NPs of potential benefit to the AD process could be divided into three groups: (i) zero-valent iron (ZVI) NPs, (ii) metallic and metal oxides NPs, and (iii) carbon-based NPs. The present review focuses on the latest findings reported on the application of these NPs in AD process and presents their various mechanisms of action leading to higher or lower biogas production rates. Among the NPs studies, ZVI NPs could be regarded as the most promising nanomaterials for enhancing biogas production through stabilizing the AD process as well as by stimulating the growth of beneficial microorganisms to the AD process and the enzymes involved. Future research should focus on various attributes of NPs when used as additives in biogas production, including facilitating mixing and pumping operations, enriching the population and diversity of beneficial microorganisms for AD, improving biogas release, and inducing the production and activity of AD-related enzymes. The higher volume of methane-enriched biogas would be translated into higher returns on investment and could therefore, result in further growth of the biogas production industry. Nevertheless, efforts should be devoted to decreasing the price of NPs so that the enhanced biogas and methane production (by over 90%, compared to control) would be more economically justified, facilitating the large-scale application of these compounds. In addition to economic considerations, environmental issues are also regarded as major constraints which should be addressed prior to widespread implementation of NP-augmented AD processes. More specifically, the fate of NPs augmented in AD process should be scrutinized to ensure maximal beneficial impacts while adverse environmental/health consequences are minimized.
The first objective of this study was to investigate the relationship between concentrations of beta-hydroxybutyrate (BHBA) in milk and blood to assess the reliability of the BHBA concentrations in milk measured by a semi quantitative keto-test paper to detect subclinical ketosis (SCK) in 50 fresh high-producing Iranian Holstein cows in Golestan Province, Iran. The second objective was the effects of SCK on milk yield and components. Concentrations of nonesterified fatty acids (NEFA) and BHBA were analyzed quantitatively in blood plasma and commercial keto-test paper was used for semi quantitative determination of BHBA concentration in milk. Milk yield was measured until 60 d after calving but milk compositions were measured until 30 d after calving. The mean plasma BHBA, milk BHBA, plasma NEFA, milk yield, milk fat percentage and milk fat: protein ratio were 1,234 micromol/L, 145 micromol/L, 0.482 mEq/L, 29.5 kg, 3.9% and 1.4, respectively. Fifty eight percent of the cows had SCK during the first month of lactation. High correlation coefficients were observed between blood BHBA and blood NEFA, and between blood and milk BHBA. The milk yield of cattle with SCK decreased (P < 0.01) but the fat percentage and milk fat: protein ratio increased (P < 0.01). The commercial keto-test paper used had a low false positive result at a cut-off point of 200 fmol of BHBA/L of milk. The results showed that the best time to assess SCK using the commercial keto-test paper was d 10, 14 and 17 after calving.
The increasing emphasis on the development of green replacements to traditional organic solvents and ionic liquids (ILs) can be attributed to the rising concerns over human health and detrimental impacts of conventional solvents towards the environment. A new generation of solvents inspired by nature and extracted from plant bioresources has evolved over the last few years, and are referred to as natural deep eutectic solvents (NADES). NADES are mixtures of natural constituents like sugars, polyalcohols, sugar-based alcohols, amino acids and organic acids. Interest in NADES has exponentially grown over the last eight years, which is evident from an upsurge in the number of research projects undertaken. NADES are highly biocompatible as they can be biosynthesized and metabolized by nearly all living organisms. These solvents pose several noteworthy advantages, such as easy synthesis, tuneable physico-chemical properties, low toxicity, high biodegradability, solute sustainability and stabilization and low melting point. Research on the applicability of NADES in diverse areas is gaining momentum, which includes as - media for chemical and enzymatic reactions; extraction media for essential oils; anti-inflammatory and antimicrobial agent; extraction of bioactive composites; as chromatographic media; preservatives for labile compounds and in drug synthesis. This review gives a complete overview of the properties, biodegradability and toxicity of NADES which we propose can assist in further knowledge generation on their significance in biological systems and usage in green and sustainable chemistry. Information on applications of NADES in biomedical, therapeutic and pharma-biotechnology fields is also highlighted in the current article along with the recent progress and future perspectives in novel applications of NADES.
Exploitation of renewable sources of energy such as algal biodiesel could turn energy supplies problem around. Studies on a locally isolated strain of Dunaliella sp. showed that the mean lipid content in cultures enriched by 200 mg L(-1) myoinositol was raised by around 33% (1.5 times higher than the control). Similarly, higher lipid productivity values were achieved in cultures treated by 100 and 200 mg L(-1) myoinositol. Fluorometry analyses (microplate fluorescence and flow cytometry) revealed increased oil accumulation in the Nile red-stained algal samples. Moreover, it was predicted that biodiesel produced from myoinositol-treated cells possessed improved oxidative stability, cetane number, and cloud point values. From the genomic point of view, real-time analyses revealed that myoinositol negatively influenced transcript abundance of AccD gene (one of the key genes involved in lipid production pathway) due to feedback inhibition and that its positive effect must have been exerted through other genes. The findings of the current research are not to interprete that myoinositol supplementation could answer all the challenges faced in microalgal biodiesel production but instead to show that "there is a there there" for biochemical modulation strategies, which we achieved, increased algal oil quantity and enhanced resultant biodiesel quality.
Investment in biofuels as sustainable alternatives for fossil fuels has gained momentum over the last decade due to the global environmental and health concerns regarding fossil fuel consumption. Hence, effective management of biofuel supply chain (BSC) components, including biomass feedstock production, biomass logistics, biofuel production in biorefineries, and biofuel distribution to consumers, is crucial in transitioning towards a low-carbon and circular economy (CE). The present study aims to render an inclusive knowledge map of the BSC-related scientific production. In this vein, a systematic review, supported by a keywords co-occurrence analysis and qualitative content analysis, was carried out on a total of 1975 peer-reviewed journal articles in the target literature. The analysis revealed four major research hotspots in the BSC literature, including (1) biomass-to-biofuel supply chain design and planning, (2) environmental impacts of biofuel production, (3) biomass to bioenergy, and (4) techno-economic analysis of biofuel production. Besides, the findings showed that the following subject areas of research in the BSC research community have recently attracted more attention: (i) global warming and climate change mitigation, (ii) development of the third-generation biofuels produced from algal biomass, which has recently gained momentum in the CE debate, and (iii) government incentives, pricing, and subsidizing policies. The provided insights shed light on the understanding of researchers, stakeholders, and policy-makers involved in the sustainable energy sector by outlining the main research backgrounds, developments, and tendencies within the BSC arena. Looking at the provided knowledge map, potential research directions in BSCs towards implementing the CE model, including (i) integrative policy convergence at macro, meso, and micro levels, and (ii) industrializing algae-based biofuel production towards the CE transition, were proposed.
This study assesses the environmental impact of pine chip-based biorefinery processes, focusing on bioethanol, xylonic acid, and lignin production. A cradle-to-gate Life Cycle Assessment (LCA) is employed, comparing a novel biphasic pretreatment method (p-toluenesulfonic acid (TsOH)/pentanol, Sc-1) with conventional sulfuric acid pretreatment (H2SO4, Sc-2). The analysis spans biomass handling, pretreatment, enzymatic hydrolysis, yeast fermentation, and distillation. Sc-1 yielded an environmental impact of 1.45E+01 kPt, predominantly affecting human health (96.55%), followed by ecosystems (3.07%) and resources (0.38%). Bioethanol, xylonic acid, and lignin contributed 32.61%, 29.28%, and 38.11% to the total environmental burdens, respectively. Sc-2 resulted in an environmental burden of 1.64E+01 kPt, with a primary impact on human health (96.56%) and smaller roles for ecosystems (3.07%) and resources (0.38%). Bioethanol, xylonic acid, and lignin contributed differently at 22.59%, 12.5%, and 64.91%, respectively. Electricity generation was predominant in both scenarios, accounting for 99.05% of the environmental impact, primarily driven by its extensive usage in biomass handling and pretreatment processes. Sc-1 demonstrated a 13.05% lower environmental impact than Sc-2 due to decreased electricity consumption and increased bioethanol and xylonic acid outputs. This study highlights the pivotal role of pretreatment methods in wood-based biorefineries and underscores the urgency of sustainable alternatives like TsOH/pentanol. Additionally, adopting greener electricity generation, advanced technologies, and process optimization are crucial for reducing the environmental footprint of waste-based biorefineries while preserving valuable bioproduct production.
This study critically reviews the recent developments and future opportunities pertinent to the conversion of CO2 as a potent greenhouse gas (GHG) to fuels and valuable products. CO2 emissions have reached an alarming level of around 410 ppm and have become the primary driver of global warming and climate change leading to devastating events such as droughts, hurricanes, torrential rains, floods, tornados and wildfires across the world. These events are responsible for thousands of deaths and have adversely affected the economic development of many countries, loss of billions of dollars, across the globe. One of the promising choices to tackle this issue is carbon sequestration by pre- and post-combustion processes and oxyfuel combustion. The captured CO2 can be converted into fuels and valuable products, including methanol, dimethyl ether (DME), and methane (CH4). The efficient use of the sequestered CO2 for the desalinization might be critical in overcoming water scarcity and energy issues in developing countries. Using the sequestered CO2 to produce algae in combination with wastewater, and producing biofuels is among the promising strategies. Many methods, like direct combustion, fermentation, transesterification, pyrolysis, anaerobic digestion (AD), and gasification, can be used for the conversion of algae into biofuel. Direct air capturing (DAC) is another productive technique for absorbing CO2 from the atmosphere and converting it into various useful energy resources like CH4. These methods can effectively tackle the issues of climate change, water security, and energy crises. However, future research is required to make these conversion methods cost-effective and commercially applicable.
Crustacean waste, consisting of shells and other inedible fractions, represents an underutilized source of chitin. Here, we explore developments in the field of crustacean-waste-derived chitin and chitosan extraction and utilization, evaluating emerging food systems and biotechnological applications associated with this globally abundant waste stream. We consider how improving the efficiency and selectivity of chitin separation from wastes, redesigning its chemical structure to improve biotechnology-derived chitosan, converting it into value-added chemicals, and developing new applications for chitin (such as the fabrication of advanced nanomaterials used in fully biobased electric devices) can contribute towards the United Nations Sustainable Development Goals. Finally, we consider how gaps in the research could be filled and future opportunities could be developed to make optimal use of this important waste stream for food systems and beyond.
Large amounts of agricultural waste, especially marine product waste, are produced annually. These wastes can be used to produce compounds with high-added value. Chitosan is one such valuable product that can be obtained from crustacean wastes. Various biological activities of chitosan and its derivatives, especially antimicrobial, antioxidant, and anticancer properties, have been confirmed by many studies. The unique characteristics of chitosan, especially chitosan nanocarriers, have led to the expansion of using chitosan in various sectors, especially in biomedical sciences and food industries. On the other hand, essential oils, known as volatile and aromatic compounds of plants, have attracted the attention of researchers in recent years. Like chitosan, essential oils have various biological activities, including antimicrobial, antioxidant, and anticancer. In recent years, one of the ways to improve the biological properties of chitosan is to use essential oils encapsulated in chitosan nanocarriers. Among the various biological activities of chitosan nanocarriers containing essential oils, most studies conducted in recent years have been in the field of antimicrobial activity. It was documented that the antimicrobial activity was increased by reducing the size of chitosan particles in the nanoscale. In addition, the antimicrobial activity was intensified when essential oils were in the structure of chitosan nanoparticles. Essential oils can increase the antimicrobial activity of chitosan nanoparticles with synergistic effects. Using essential oils in the structure of chitosan nanocarriers can also improve the other biological properties (antioxidant and anticancer activities) of chitosan and increase the application fields of chitosan. Of course, using essential oils in chitosan nanocarriers for commercial use requires more studies, including stability during storage and effectiveness in real environments. This review aims to overview recent studies on the biological effects of essential oils encapsulated in chitosan nanocarriers, with notes on their biological mechanisms.
Depending on its physicochemical properties and antibacterial activities, chitosan can have a wide range of applications in food, pharmaceutical, medicine, cosmetics, agriculture, and aquaculture. In this experimental study, chitosan was extracted from shrimp waste through conventional extraction, microwave-assisted extraction, and conventional extraction under microwave process conditions. The effects of the heating source on the physicochemical properties and antibacterial activity were investigated. The results showed that the heating process parameters affected the physicochemical properties considerably. The conventional procedure yielded high molecular weight chitosan with a 12.7 % yield, while the microwave extraction procedure yielded a porous medium molecular weight chitosan at 11.8 %. The conventional extraction under microwave process conditions led to medium molecular weight chitosan with the lowest yield (10.8 %) and crystallinity index (79 %). Antibacterial assessment findings revealed that the chitosan extracted using the conventional method had the best antibacterial activity in the agar disk diffusion assay against Listeria monocytogenes (9.48 mm), Escherichia coli. (8.79 mm), and Salmonella Typhimurium (8.57 mm). While the chitosan obtained by microwave-assisted extraction possessed the highest activity against E. coli. (8.37 mm), and Staphylococcus aureus (8.05 mm), with comparable antibacterial activity against S. Typhimurium (7.34 mm) and L. monocytogenes (6.52 mm). Moreover, the minimal inhibitory concentration and minimal bactericidal concentration assays demonstrated that among the chitosan samples investigated, the conventionally-extracted chitosan, followed by the chitosan extracted by microwave, had the best antibacterial activity against the target bacteria.
A comprehensive exergoeconomic performance analysis of a municipal solid waste digestion plant integrated with a biogas genset was conducted throughout this study in order to highlight its bottlenecks for further improvements. Exergoeconomic performance parameters of each component of the plant were determined by solving exergy and cost balance equations based on Specific Exergy Costing (SPECO) approach. The analysis was conducted to reveal the cost structure of the plant based on actual operating information and economic data. The exergy unitary cost of two main products of the plant, i.e., bioelectricity and biofertilizer were determined at 26.27 and 2.27 USD/GJ, respectively. The genset showed the highest overall cost rate (101.27 USD/h) followed by digester (68.41 USD/h). Furthermore, the net bioelectricity amounted to 67.81% of the overall cost rate of the products, while this value was 32.19% for both liquid and dewatered digestates. According to the results obtained, efforts should mainly focus on enhancing the efficiency of the genset in order to boost the overall performance of the system exergoeconomically. In addition, minimizing the investment-related cost of the digester could also substantially enhance the exergoeconomic performance of the plant.
Chitin, as the main component of the exoskeleton of Arthropoda, is a highly available natural polymer that can be processed into various value-added products. Its most important derivative, i.e., chitosan, comprising β-1,4-linked 2-amino-2-deoxy-β-d-glucose (deacetylated d-glucosamine) and N-acetyl-d-glucosamine units, can be prepared via alkaline deacetylation process. Chitosan has been used as a biodegradable, biocompatible, non-antigenic, and nontoxic polymer in some in-vitro applications, but the recently found potentials of chitosan for in-vivo applications based on its biological activities, especially antimicrobial, antioxidant, and anticancer activities, have upgraded the chitosan roles in biomaterials. Chitosan approval, generally recognized as a safe compound by the United States Food and Drug Administration, has attracted much attention toward its possible applications in diverse fields, especially biomedicine and agriculture. Despite some favorable characteristics, the chitosan's structure should be customized for advanced applications, especially due to its drawbacks, such as low drug-load capacity, low solubility, high viscosity, lack of elastic properties, and pH sensitivity. In this context, derivatization with relatively inexpensive and highly available mono- and di-saccharides to soluble branched chitosan has been considered a "game changer". This review critically scrutinizes the emerging technologies based on the synthesis and application of lactose- and galactose-modified chitosan as two important chitosan derivatives. Some characteristics of chitosan derivatives and biological activities have been detailed first to understand the value of these natural polymers. Second, the saccharide modification of chitosan has been discussed briefly. Finally, the applications of lactose- and galactose-modified chitosan have been scrutinized and compared to native chitosan to provide an insight into the current state-of-the research for stimulating new ideas with the potential of filling research gaps.
The rapid development of the textile industry and improvement of people's living standards have led to the production of cotton textile and simultaneously increased the production of textile wastes. Cotton is one of the most common textile materials, and the waste cotton accounts for 24% of the total textile waste. To effectively manage the waste, recycling and reusing waste cotton are common practices to reduce global waste production. This paper summarizes the characteristics of waste cotton and high-value products derived from waste cotton (e.g., yarns, composite reinforcements, regenerated cellulose fibers, cellulose nanocrystals, adsorptive materials, flexible electronic devices, and biofuels) via mechanical, chemical, and biological recycling methods. The advantages and disadvantages of making high-value products from waste cotton are summarized and discussed. New technologies and products for recycling waste cotton are proposed, providing a guideline and direction for merchants and researchers. This review paper can shed light on converting textile wastes other than cotton (e.g., bast, silk, wool, and synthetic fibers) into value-added products.
In order to develop a product sustainably, multiple analyses, including comprehensive environmental assessment, are required. Solar-assisted production of walnut husk methanolic extract (WHME) as a natural antioxidant for biodiesel was scrutinized by using the life cycle assessment (LCA) approach. More specifically, the environmental sustainability of WHME antioxidant was evaluated and compared to that of propyl gallate (PG), the most widely used synthetic biodiesel antioxidant, under two scenarios. Additionally, supplementary files including the inventory data consisting of raw data as well as elementary flows, mid-point, and end-point categories are presented. The analysis of scenarios revealed that the use of the natural antioxidant and the avoidance of the chemical antioxidant in biodiesel fuel could be regarded as an eco-friendly approach substantially enhancing the environmental friendliness of biodiesel in particular in terms of human health. Furthermore, given the waste-oriented nature of WHME, the scenario involved its application could serve as a promising strategy to simultaneously valorize the agro-waste and generate a value-added product; a move toward implementing the circular economy approach in the biodiesel industry.
Integrated environmental analysis using life cycle assessment for different fuel blends used in a single-cylinder diesel engine was performed to select the most eco-friendly fuel blend. More specifically, the inventory data in support of the integrated environmental analysis of water-emulsified 5% biodiesel/diesel blends (B5) containing different levels of carbon nanoparticles (i.e., 38, 75, and 150 µM) as a novel fuel nanoadditives at a fixed engine speed of 1000 rpm and four different engine loads (i.e., 25, 50, 75, and 100%) are presented. Neat diesel, B5, and B5 containing water (3 wt.%) were used as controls. Raw data related to the production and combustion of fuel blends were experimentally collected. Industrial (i.e., experiments at large scale) and laboratory (i.e., experiments at small scale) data were used for fuel blends production while experimental data obtained by engine tests were used for the combustion stage. Then raw data were processed with the IMPACT 2002+ methods by using the SimaPro software and EcoInvent database and were then converted into environmental impacts. Accordingly, six supplementary files including the inventory data on integrated environmental analysis of the different fuel blends are presented (Supplementary Files 1-6). The data could be applied for integrated environmental analysis in order to avoid subjective weighting of combustion parameters for selecting the most eco-friendly fuel blend for use in diesel engines. More specifically, by developing a single score indicator obtained through conducting integrated combustion analysis, comparison of various fuel blends is largely facilitated.
Five cyanobacterial strains with Nostoc-like morphology from different localities of the Mazandaran province of Iran were characterized using a polyphasic approach. Three strains clustered within the Aliinostoc clade whereas one each of the remaining two strains clustered within the genera Desmonostoc and Desikacharya. The phylogenetic positioning of all the strains by the bayesian inference, neighbour joining and maximum parsimony methods inferred using 16S rRNA gene indicated them to represent novel species of the genera Aliinostoc, Desmonostoc and Desikacharya. The 16S-23S ITS secondary structure analysis revealed that all five strains under study represented novel species unknown to science. In accordance with the International Code of Nomenclature for algae, fungi and plants we describe three novel species of the genus Aliinostoc and one species each of the genera Desmonostoc and Desikacharya.