Production of High-Value Nanoparticles via Biogenic Processes Using Aquacultural and Horticultural Food Waste

Copper nanoparticles biosynthesis by Priestia megaterium and its application as antibacterial and antitumor agents

The growth of material science and technology places high importance on creating better processes for synthesizing copper nanoparticles. Thus, an easy, ecological, and benign process for producing copper nanoparticles (CuNPs) has been developed using Priestia sp. bacteria utilizing a variety of low-cost agro-industrial wastes and byproducts. The biosynthesis of CuNPs was conducted using glucose medium and copper ions salt solution, then it was replaced by utilizing low-cost agro-industrial wastes. UV-visible spectroscopy, dynamic light scattering (DLS), X-ray diffraction (XRD), High-resolution transmission electron microscope (HR-TEM), Attenuated Total Reflectance and Fourier transform infrared (ATR-FTIR), and zeta potential were used to characterize the biosynthesized CuNPs. The cytotoxicity of CuNPs using Vero -CCL-81 cell lines, and antibacterial and antitumor properties using human colon epithelial colorectal adenocarcinoma Caco-2-HTB-37 cell lines were assessed. The UV-visible and DLS studies revealed CuNPs formation, with a maximum concentration of 6.19 ppm after 48 h, as indicated by a 0.58 Surface plasmon resonance (SPR) within 450 nm and 57.73 nm particle size. The 16S rRNA gene analysis revealed that Priestia sp. isolate is closely related to Priestia megaterium and has been deposited in the NCBI GenBank with accession number AMD 2024. The biosynthesis with various agro-industrial wastes indicated blackstrap sugar cane molasses being the most effective for reducing CuNPs size to 3.12 nm owing to various reducing and stabilizing active compounds. The CuNPs were free of contaminants, with a sphere-shaped structure and a cytotoxicity assessment with an IC50 of 367.27 μg/mL. The antibacterial activity exhibited by the most susceptible bacteria were Bacillus cereus ATCC 11788 and Staphylococcus aureus ATCC 6538 with inhibition zones of 26.0 mm and 28.0 mm, respectively. The antitumor effect showed an IC50 dose of 175.36 μg/mL. Based on the findings, the current work sought to lower product costs and provide a practical solution to the environmental contamination issues brought on by the buildup of agricultural wastes. In addition, the obtained CuNPs could be applied in many fields such as pharmaceuticals, water purification, and agricultural applications as future aspects.

A Comprehensive Review on the Importance of Sustainable Synthesized Coinage Metal Nanomaterials and Their Diverse Biomedical Applications

From a historical perspective, coinage metals (CMNMs) are most renowned for their monetary, ornamental, and metallurgical merits; nevertheless, as nanotechnology's potential has only just come to light, their metal nanostructures and uses may be viewed as products of modern science. Notable characteristics of CMNMs include visual, electrical, chemical, and catalytic qualities that depend on shape and size. Due diligence on the creation and synthesis of CMNMs and their possible uses has been greatly promoted by these characteristics. This review focuses on solution-based methods and provides an overview of the latest developments in CMNMs and their bimetallic nanostructures. It discusses a range of synthetic techniques, including conventional procedures and more modern approaches used to enhance functionality by successfully manipulating the CMNMs nanostructure's size, shape, and composition. To help with the design of new nanostructures with improved capabilities in the future, this study offers a brief assessment of the difficulties and potential future directions of these intriguing metal nanostructures. This review focuses on mechanisms and factors influencing the synthesis process, green synthesis, and sustainable synthesis methods. It also discusses the wide range of biological domains in which CMNMs are applied, including antibacterial, antifungal, and anticancer. Researchers will therefore find the appropriateness of both synthesizing and using CMNMS keeping in mind the different levels of environmental effects.

Biogenic nanoparticles from waste fruit peels: Synthesis, applications, challenges and future perspectives

Nanotechnology is a continually growing field with a wide range of applications from food science to biotechnology and nanobiotechnology. As the current world is grappling with non-biodegradable waste, considered more challenging and expensive to dispose of than biodegradable waste, new technologies are needed today more than ever. Modern technologies, especially nanotechnology, can transform biodegradable waste into products for human use. Researchers are exploring sustainable pathways for nanotechnology by utilizing biodegradable waste as a source for preparing nanomaterials. Over the past ten years, the biogenic production of metallic nanoparticles (NPs) has become a promising alternative technique to traditional NPs synthesis due to its simplicity, eco-friendliness, and biocompatibility in nature. Fruit and vegetable waste (after industrial processing) contain various bioactives (such as flavonoids, phenols, tannins, steroids, triterpenoids, glycosides, anthocyanins, carotenoids, ellagitannins, vitamin C, and essential oils) serving as reducing and capping agents for NP synthesis and they possess antibacterial, antioxidant, and anti-inflammatory properties. This review addresses various sources of biogenic NPs including their synthesis using fruit/vegetable waste, types of biogenic NPs, extraction processes and extracted biomaterials, the pharmacological functionality of NPs, industrial aspects, and future perspectives. In this manner, this review will cover the most recent research on the biogenic synthesis of NPs from fruit/vegetable peels to transform them into therapeutic nanomedicines.

Review on Surface-Modified Electrodes for the Enhanced Electrochemical Detection of Selective Serotonin Reuptake Inhibitors (SSRIs)

Selective serotonin re-uptake inhibitors (SSRIs) are one of the most commonly prescribed classes of antidepressants used for the treatment of moderate to severe depressive disorder, personality disorders and various phobias. This class of antidepressants was created with improved margins of safety. However, genetic polymorphism may be responsible for the high variability in patients' responses to treatment, ranging from failure to delayed therapeutic responses to severe adverse effects of treatment. It is crucial that the appropriate amount of SSRI drugs is administered to ensure the optimum therapeutic efficacy and intervention to minimise severe and toxic effects in patients, which may be the result of accidental and deliberate cases of poisoning. Determining SSRI concentration in human fluids and the environment with high sensitivity, specificity and reproducibility, and at a low cost and real-time monitoring, is imperative. Electrochemical sensors with advanced functional materials have drawn the attention of researchers as a result of these advantages over conventional techniques. This review article aims to present functional materials such as polymers, carbon nanomaterials, metal nanomaterials as well as composites for surface modification of electrodes for sensitive detection and quantification of SSRIs, including fluoxetine, citalopram, paroxetine, fluvoxamine and sertraline. Sensor fabrication, sensor/analyte interactions, design rationale and properties of functional material and the electrocatalytic effect of the modified electrode on SSRI detection are discussed.

Current Technologies and Uses for Fruit and Vegetable Wastes in a Sustainable System: A Review

The fruit and vegetable industry produces millions of tons of residues, which can cause large economic losses. Fruit and vegetable wastes and by-products contain a large number of bioactive substances with functional ingredients that have antioxidant, antibacterial, and other properties. Current technologies can utilize fruit and vegetable waste and by-products as ingredients, food bioactive compounds, and biofuels. Traditional and commercial utilization in the food industry includes such technologies as microwave-assisted extraction (MAE), supercritical fluid extraction (SFE), ultrasonic-assisted extraction (UAE), and high hydrostatic pressure technique (HHP). Biorefinery methods for converting fruit and vegetable wastes into biofuels, such as anaerobic digestion (AD), fermentation, incineration, pyrolysis and gasification, and hydrothermal carbonization, are described. This study provides strategies for the processing of fruit and vegetable wastes using eco-friendly technologies and lays a foundation for the utilization of fruit and vegetable loss/waste and by-products in a sustainable system.

Phyto-Assisted Synthesis of Nanoselenium-Surface Modification and Stabilization by Polyphenols and Pectins Derived from Agricultural Wastes

Raw and purified mandarin peel-derived pectins were characterized and combined with olive pomace extract (OPE) in the green synthesis of selenium nanoparticles (SeNPs). SeNPs were characterized in terms of size distribution and zeta potential, and their stability was monitored during 30 days of storage. HepG2 and Caco-2 cell models were used for the assessment of biocompatibility, while antioxidant activity was investigated by the combination of chemical and cellular-based assays. SeNP average diameters ranged from 171.3 nm up to 216.9 nm; smaller SeNPs were obtained by the utilization of purified pectins, and functionalization with OPE slightly increased the average. At concentrations of 15 mg/L SeNPs were found to be biocompatible, and their toxicity was significantly lower in comparison to inorganic selenium forms. Functionalization of SeNPs with OPE increased their antioxidant activity in chemical models. The effect was not clear in cell-based models, even though all investigated SeNPs improved cell viability and protected intracellular reduced GSH under induced oxidative stress conditions in both investigated cell lines. Exposure of cell lines to SeNPs did not prevent ROS formation after exposure to prooxidant, probably due to low transepithelial permeability. Future studies should focus on further improving the bioavailability/permeability of SeNPs and enhancing the utilization of easily available secondary raw materials in the process of phyto-mediated SeNP synthesis.

Green synthesis of nanoparticles from biodegradable waste extracts and their applications: a critical review

The contemporary world is concerned only with non-biodegradable waste management which needs more sophisticated procedures as compared to biodegradable waste management. Biodegradable waste has the potential to become useful to society through a simple volarization technique. The researchers are behind sustainable nanotechnology pathways which are made possible by using biodegradable waste for the preparation of nanomaterials. This review emphasizes the potentialities of biodegradable waste produced as a viable alternative to create a sustainable economy that benefits all humans. Volarization results in the utilization of biowastes as well as provides safer and hazard-free green methods for the synthesis of nanoparticles. Starting from different sources to the application which includes therapeutics, food industry and water treatment. The review hovers over the pros and cons of biowaste-mediated nanoparticles and concludes with possible advances in the application. In the present scenario, the combination of green synthesis and biowaste can bring about a wide variety of applications in nanotechnology once the hurdles of bulk-scale industrial production are resolved. Given these points, the review is focused on the cost-effective synthesis of metal and metal oxide nanoparticles.

Effects of Waste-Derived ZnO Nanoparticles against Growth of Plant Pathogenic Bacteria and Epidermoid Carcinoma Cells

Green synthesis of zinc oxide nanoparticles (ZnO NPs) has recently gained considerable interest because it is simple, environmentally friendly, and cost-effective. This study therefore aimed to synthesize ZnO NPs by utilizing bioactive compounds derived from waste materials, mangosteen peels, and water hyacinth crude extracts and investigated their antibacterial and anticancer activities. As a result, X-ray diffraction analysis confirmed the presence of ZnO NPs without impurities. An ultraviolet–visible absorption spectrum showed a specific absorbance peak around 365 nm with an average electronic band gap of 2.79 eV and 2.88 eV for ZnO NPs from mangosteen peels and a water hyacinth extract, respectively. An SEM analysis displayed both spherical shapes of ZnO NPs from the mangosteen peel extract (dimension of 154.41 × 172.89 nm) and the water hyacinth extract (dimension of 142.16 × 160.30 nm). Fourier transform infrared spectroscopy further validated the occurrence of bioactive molecules on the produced ZnO NPs. By performing an antibacterial activity assay, these green synthesized ZnO NPs significantly inhibited the growth of Xanthomonas oryzae pv. oryzae, Xanthomonas axonopodis pv. citri, and Ralstonia solanacearum. Moreover, they demonstrated potent anti-skin cancer activity in vitro. Consequently, this study demonstrated the possibility of using green-synthesized ZnO NPs in the development of antibacterial or anticancer agents. Furthermore, this research raised the prospect of increasing the value of agricultural waste.

Current advancements on the fabrication, modification, and industrial application of zinc oxide as photocatalyst in the removal of organic and inorganic contaminants in aquatic systems

Industrial wastewaters contain hazardous contaminants that pollute the environment and cause socioeconomic problems, thus demanding the employment of effective remediation procedures such as photocatalysis. Zinc oxide (ZnO) nanomaterials have emerged to be a promising photocatalyst for the removal of pollutants in wastewater owing to their excellent and attractive characteristics. The dynamic tunable features of ZnO allow a wide range of functionalization for enhanced photocatalytic efficiency. The current review summarizes the recent advances in the fabrication, modification, and industrial application of ZnO photocatalyst based on the analysis of the latest studies, including the following aspects: (1) overview on the properties, structures, and features of ZnO, (2) employment of dopants, heterojunction, and immobilization techniques for improved photodegradation performance, (3) applicability of suspended and immobilized photocatalytic systems, (4) application of ZnO hybrids for the removal of various types of hazardous pollutants from different wastewater sources in industries, and (5) potential of bio-inspired ZnO hybrid nanomaterials for photocatalytic applications using renewable and biodegradable resources for greener photocatalytic technologies. In addition, the knowledge gap in this field of work is also highlighted.

Valorizing the Unexplored Filtration Waste of Brewing Industry for Green Silver Nanocomposite Synthesis

The brewing industry generates a substantial amount of by-products rich in polyphenols, carbohydrates, sugars, sulfates, nitrogen compounds, organic carbon, and several elements, including chlorine, magnesium, and phosphorus. Although limited quantities of these by-products are used in fertilizers and composts, a large amount is discarded as waste. Therefore, it is crucial to identify different ways of valorizing the by-products. Research regarding the valorization of the brewery by-products is still in its nascent stage; therefore, it still has high potential. Herein, we report the valorization of the brewery by-product from the filtration stage of the brewing process (BW9) to synthesize silver nanocomposites as this waste has remained largely unexplored. The BW9 nanocomposites have been compared to those obtained from the brewery product B. The chemical composition analysis of BW9 and B revealed several organic moieties capable of reducing metal salts and capping the formed nanoparticles. Therefore, the brewery waste from stage 9 was valorized as a precursor and added to silver-based precursor at various temperatures (25, 50, and 80 °C) and for various time periods (10, 30, and 120 min) to synthesize silver nanocomposites. The nanocomposites obtained using BW9 were compared to those obtained using the main product of the brewing industry, beer (B). Synthesized nanocomposites composed of AgCl as a major phase and silver metal (Ag_met) was incorporated in minor quantities. In addition, Ag₃PO₄ was also found in B nanocomposites in minor quantities (up to 34 wt.%). The surface morphology depicted globular nanoparticles with layered structures. Small ball-like aggregates on the layer representative of Ag₃PO₄ were observed in B nanocomposites. The surface of nanocomposites was capped with organic content and functional groups present in the brewery products. The nanocomposites demonstrated high antibacterial activity against Escherichia coli (E. coli), with BW9 nanocomposites exhibiting a higher activity than B nanocomposites.

Organic waste valorisation towards circular and sustainable biocomposites

Organic waste valorisation into biopolymers and nanofillers potentially lowers the pressure on non-renewable resources, avoids the generation of waste-streams and opens new opportunities to develop multifunctional bio-based products.

Valorization of Brewery Wastes for the Synthesis of Silver Nanocomposites Containing Orthophosphate

Brewery wastes from stage 5 (Wort precipitate: BW5) and stage 7 (Brewer's spent yeast: BW7) were valorized for the synthesis of silver phosphate nanocomposites. Nanoparticles were synthesized by converting silver salt in the presence of brewery wastes at different temperatures (25, 50, and 80 °C) and times (10, 30, and 120 min). Unexpectedly, BW7 yielded Ag3PO4 nanoparticles with minor contents of AgCl and Ag metal (Agmet). Contrastingly, BW5 produced AgCl nanoparticles with minor amounts of Ag3PO4 and Agmet. Nanocomposites with different component ratios were obtained by simply varying the synthesis temperature and time. The morphology of the nanocomposites contained ball-like structures representative of Ag3PO4 and stacked layers and fused particles representing AgCl and Agmet. The capping on the nanoparticles contained organic groups from the brewery by-products, and the surface overlayer had a rich chemical composition. The organic overlayers on BW7 nanocomposites were thinner than those on BW5 nanocomposites. Notably, the nanocomposites exhibited high antibacterial activity against Escherichia coli ATCC 25922. The antibacterial activity was higher for BW7 nanocomposites due to a larger silver phosphate content in the composition and a thin organic overlayer. The growth of Agmet in the structure adversely affected the antimicrobial property of the nanocomposites.

Plant celluloses, hemicelluloses, lignins, and volatile oils for the synthesis of nanoparticles and nanostructured materials

A huge variety of plants are harvested worldwide and their different constituents can be converted into a broad range of bionanomaterials. In parallel, much research effort in materials science and engineering is focused on the formation of nanoparticles and nanostructured materials originating from agricultural residues. Cellulose (40-50%), hemicellulose (20-40%), and lignin (20-30%) represent major plant ingredients and many techniques have been described that separate the main plant components for the synthesis of nanocelluloses, nano-hemicelluloses, and nanolignins with divergent and controllable properties. The minor components, such as essential oils, could also be used to produce non-toxic metal and metal oxide nanoparticles with high bioavailability, biocompatibility, and/or bioactivity. This review describes the chemical structure, the physical and chemical properties of plant cell constituents, different techniques for the synthesis of nanocelluloses, nanohemicelluloses, and nanolignins from various lignocellulose sources and agricultural residues, and the extraction of volatile oils from plants as well as their use in metal and metal oxide nanoparticle production and emulsion preparation. Furthermore, details about the formation of activated carbon nanomaterials by thermal treatment of lignocellulose materials, a few examples of mineral extraction from agriculture waste for nanoparticle fabrication, and the emerging applications of plant-based nanomaterials in different fields, such as biotechnology and medicine, environment protection, environmental remediation, or energy production and storage, are also included. This review also briefly discusses the recent developments and challenges of obtaining nanomaterials from plant residues, and the issues surrounding toxicity and regulation.

Fruit and Vegetable Peels: Utilization of High Value Horticultural Waste in Novel Industrial Applications

Fruits and vegetables are the highly used food products amongst the horticultural crops. These items are consumed uncooked, nominally cooked or fully cooked, according to their nature and cooking process. With the change in diet habits and rising population, the production, as well as the processing of horticultural crops, has exponentially improved to meet its increasing demand. A large amount of peel waste is generated from fruit and vegetable-based industries and household kitchen and has led to a big nutritional and economic loss and environmental problems. Processing of fruits and vegetables alone generates a significant waste, which amounts to 25-30% of the total product. Most common wastes include pomace, peels, rind and seeds, which are highly rich in valuable bioactive compounds such as carotenoids, enzymes, polyphenols, oils, vitamins and many other compounds. These bioactive compounds show their application in various industries such as food to develop edible films, food industries for probiotics and other industries for valuable products. The utilization of these low-cost waste horticultural wastes for producing the value-added product is a novel step in its sustainable utilization. The present review intends to summarize the different types of waste originating from fruits as well as vegetables peels and highlight their potential in developing edible films, probiotics, nanoparticles, carbon dots, microbial media, biochar and biosorbents.

Comparative study on antidiabetic, cytotoxicity, antioxidant and antibacterial properties of biosynthesized silver nanoparticles using outer peels of two varieties of Ipomoea batatas (L.) Lam

BACKGROUND

Ipomoea batatas (L.) Lam.(Ib) has high content of various beneficial nutrients which helps in improving and maintaining human health. It is well known as a functional food and also a valuable source of unique natural products. It contains various phenolic and flavonoid bioactive compounds.

METHODS

In this study, using the outer peel of two varieties of Ib : Korean red skin sweet potato and Korean pumpkin sweet potato, silver nanoparticles (AgNPs) were synthesized (termed Ib1-AgNps and Ib2-AgNps), respectively. Characterization of Ib1-AgNPs and Ib2-AgNPs was carried out through scanning electron microscopy, Fourier-transform infrared (FT-IR) spectroscopy, energy-dispersive X-ray analysis, X-ray powder diffraction and UV-Vis spectroscopy. Further, the bio-potential of the synthesized AgNPs was investigated by antidiabetic (α-glucosidase assay), antioxidant (free radical scavenging assays), antibacterial (disc diffusion method) and cytotoxicity assays (cell viability against HepG2 cells).

RESULTS

FT-IR spectroscopy revealed the contribution of bioactive compounds existing in Ib1 and Ib2 extracts, in the biosynthesis and equilibrium of the AgNPs. Although the Ib2-AgNPs had a higher atomic percentage of Ag in comparison with Ib1-AgNPs, in the antidiabetic assay, the inhibition percentage of α-glucosidase was higher for AgNPs of Ib1 than Ib2, at all three concentrations examined. From the cytotoxicity results, HepG2 cancer cells were more sensitive to the Ib1-AgNPs in comparison to the Ib2-AgNPs-treated HepG2 cells. The antioxidant prospective was higher in Ib2-AgNPs than Ib1-AgNPs. Moreover, the Ib2-AgNPs showed inhibitory action against all five tested pathogenic bacteria, producing an inhibition zone of 8.74-11.52 mm while Ib1-AgNPs had an inhibitory effect on four of them, with an 8.67-11.23 (mm) inhibition zone.

CONCLUSIONS

Overall, the results concluded that the Ib2-AgNPs exhibited relatively higher functional activity than Ib1-AgNPs, which might be credited to the greater abundance of bioactive compounds existing in Ib2 extract that acted as reducing as well as capping agents in the synthesis of Ib2-AgNPs. Overall, the current study highlights a novel cost-effective and eco-friendly AgNPs synthesis using food waste peels with biocompatibility and could be potentially utilized in biomedical and pharmaceutical industries.

Photo-mediated Biosynthesis of Silver Nanoparticles Using the Non-edible Accrescent Fruiting Calyx of Physalis peruviana L. Fruits and Investigation of its Radical Scavenging Potential and Cytotoxicity Activities

Silver nanoparticles (AgNPs) have been synthesized by various ways but the green technology methods using food waste materials has been accepted now a days for their cost effectiveness, environmental friendly and effective biomedical application. In the present study an attempt has been made to synthesize AgNPs by using the outer accrescent fruiting calyx of Physalis peruviana fruits, a food waste material under different light source condition, and to investigate their cytotoxic activity against the HepG₂ cells as well as their antibacterial and radical scavenging potential. The surface morphology and elemental composition of the biosynthesized AgNPs were evaluated by scanning electron microscopy, energy-dispersive X-ray analysis, and X-ray powder diffraction analysis. Fourier transform infrared spectroscopy of the sample extract and AgNPs was performed to determine the involvement of functional groups in the synthesis, capping, and stabilization process. The AgNPs showed promising cytotoxic activity against the HepG2 cells in a dose-dependent manner. The biosynthesized AgNPs also exhibited moderate antibacterial activity (8.14-10.22 mm inhibition zones) against two Gram-negative pathogenic bacteria with promising radical scavenging potential. Overall, the results highlight the effectiveness of the AgNPs for use in antibacterial wound dressing materials and other biomedical applications for the treatment of critical diseases such as cancer.

Bactericidal Properties of Plants-Derived Metal and Metal Oxide Nanoparticles (NPs)

Nanoparticles (NPs) are nano-sized particles (generally 1–100 nm) that can be synthesized through various methods. The wide range of physicochemical characteristics of NPs permit them to have diverse biological functions. These particles are versatile and can be adopted into various applications, particularly in biomedical field. In the past five years, NPs’ roles in biomedical applications have drawn considerable attentions, and novel NPs with improved functions and reduced toxicity are continuously increasing. Extensive studies have been carried out in evaluating antibacterial potentials of NPs. The promising antibacterial effects exhibited by NPs highlight the potential of developing them into future generation of antimicrobial agents. There are various methods to synthesize NPs, and each of the method has significant implication on the biological action of NPs. Among all synthetic methods, green technology is the least toxic biological route, which is particularly suitable for biomedical applications. This mini-review provides current update on the antibacterial effects of NPs synthesized by green technology using plants. Underlying challenges in developing NPs into future antibacterials in clinics are also discussed at the present review.