The use of algae-based green synthesis of metal oxide nanoparticles (MONPs) for bioremediation is an environmentally friendly and cost-effective alternative to conventional approaches. Algal-mediated synthesis offers several benefits over other biogenic processes, such as plants, bacteria, and fungi, including ease of synthesis, scalability, and rapid synthesis. Algae are readily available in nature, nontoxic, and can produce various types of metal oxide nanoparticles. This approach could significantly accelerate the development of novel algae-nanomaterials with improved properties and performance, leading to more efficient and cost-effective bioremediation of pollutants from water solutions, seawater, and industrial effluent. This review focuses on the biogenic fabrication of metal oxide nanoparticles based on aquatic plants (microalgae and seaweeds) due to their many advantages and attractive applications in pollutant remediation from aqueous solutions. Additionally, photocatalysis is highlighted as a promising tool for the remediation of industrial effluents due to its efficacy, ease of use, quick oxidation, cost-effectiveness, and reduced synthesis of harmful byproducts.

Over the past few decades, the production of metal oxide nanoparticles (MONPs) has developed into an exciting and sophisticated research area. Green metal oxide nanoparticles have played an extremely imperative role in various fields, including biomedical, environmental, energy, agricultural applications, catalytic, bioactive, antibacterial, poisonous, and biocompatible. To achieve sustainability and adopt environmentally friendly practices, the production of MONPs is now increasingly focused on exploring green chemistry and alternative pathways. When made using green synthesis techniques, the metal oxide nanoparticles are especially important because they do not require external stabilizers, capping agents, dangerous chemicals, or harsh operating conditions (high pressure and temperature). Plant-mediated synthesis of different MONPs using either whole cells or extracts has several advantages, including rapid synthesis (compared with other biogenic processes (using fungi and bacteria)), being more stable than other types, being available in nature, and being non-toxic. This review provides a comprehensive overview of the green synthesis of MONPs using plant parts, factors affecting the synthesis, and the characterization of synthesized NPs. Additionally, it highlights the potential of these environmentally friendly nanoparticles that are widely used to treat environmental pollutants, including the removal of heavy metals, antibacterials, and the degradation of organic pollutants.

This study aimed to evaluate the effects of dietary supplementation with nano-curcumin (NCur) and a nano-curcumin/chitosan blend (NCur/Ch) on growth performance, digestibility, immune response, antioxidant status, intestinal morphometric characters, and gene regulation in Nile tilapia. Fish (n = 180, initial body weight = 12.0 ± 0.53 g) received supplementary NCur at rates of 0 (control), 0.00625, and 0.0125, and NCur/Ch at rates of 0.00625 + 0.5 g/kg diet for 4 weeks. Growth performance parameters (final weight and length, body mass gain, specific growth, and length gain rates) were markedly increased, and the feed conversion ratio was significantly decreased in the NCur- and NCur/Ch-supplemented groups. Digestive enzyme (amylase), immune response markers (immunoglobulin M, nitrous oxide, and lysozyme activity), plasma albumin, and total protein were increased significantly, mainly with a diet supplemented with 0.00625 g NCur/kg. Aspartate aminotransferase (AST), alanine aminotransferase (ALT), glucose, and cortisol levels decreased in the supplemented groups compared to the control. Significantly increased glutathione peroxidase (GPx) and decreased malondialdehyde (MDA) levels were observed in the NCur/Ch group. Superoxide dismutase (SOD) activity was improved in the 0.0125 NCur group. Intestinal morphometric characters, including villus length, width, interspace, and goblet cell abundance, were increased to cope with improved growth performance and were associated with upregulation of insulin-like growth factor 1 (igf-1) and complement C-5 (cc5) compared to the control group. Therefore, NCur and an NCur/Ch blend could be supplemented in the Nile tilapia diets as a natural alternative to promote growth, digestion, immune status, liver function, antioxidant status, and related gene expression in O. niloticus.

The current study investigated effects of garlic (Allium sativum) and/or ascorbic acid on growth performance, feed utilization, biochemical body composition, and hemato-biochemical parameters of juvenile Asian sea bass. A total of 600 fish (43.14 ± 0.23 g body weight) were divided into four groups. Fish in the first group were fed basal diet and served as a control group. Fish in groups 2, 3 and 4 were fed a basal diet mixed with garlic (40 g/kg diet), ascorbic acid (1.5 g/kg diet), or garlic (20 g/kg diet)/ascorbic acid (0.75 g/kg diet) mixture, respectively, for 12 weeks. A significant (p < 0.05) increase was observed in growth performance, feed utilization, and chemical body composition in fish fed garlic alone in comparison with the control and other treated groups. All hematological indices, biochemical parameters, and survival rate were not changed significantly (p > 0.05) in all groups throughout the experimental period when compared with the control. Total cholesterol and feed conversion ratio were significantly (p < 0.05) decreased in fish fed garlic alone in comparison to the control and other treated groups. Conclusively, dietary supplementation of garlic alone (40 g/kg diet) was highly effective in improving most of the studied parameters in comparison with that of ascorbic acid alone or a mixture of garlic (20 g/kg diet) and ascorbic acid (0.75 g/kg diet).