Purpose of ReviewThis review imparts the information on melanin as a multifunctional biomolecule, emphasizing the diversity of sources like microbial, plant, and human, and accentuating its potential as a sustainable material. It deliberately focuses on current advances in utilizing melanin for inventive applications in important areas such as food, cosmetics, environmental improvement, and agriculture, as well as its increasing significance in promoting eco-friendly and industrial solutions.Recent FindingsMelanin derived from microbial, plant, and human sources has a broad spectrum of bioactivities, which includes protection from UV radiation, strong antioxidant capabilities, and the strong ability to affiliate and neutralize environmental contaminants. Recently its natural origin and biocompatibility have caught the eye in its usage as a food coloring and preservation. Not only this, it is also known to create a spark in the cosmetic industry by providing skin protection, pigmentation balance, and anti-aging effects, with both plant- and human-derived melanin playing their important roles.Environmentally, microbial and plant-based melanin built a strong resilience in the elimination of heavy and toxic metals and compounds. In agriculture, microbial melanin is well known for improving soil health in addition to increasing plant tolerance to stress and shielding biocontrol chemicals from UV destruction and showing their high capacity and significant role in different industries, making it one of the most promising byproducts of the cellular process.Recent FindingsMelanin derived from microbial, plant, and human sources has a broad spectrum of bioactivities, which includes protection from UV radiation, strong antioxidant capabilities, and the strong ability to affiliate and neutralize environmental contaminants. Recently its natural origin and biocompatibility have caught the eye in its usage as a food coloring and preservation. Not only this, it is also known to create a spark in the cosmetic industry by providing skin protection, pigmentation balance, and anti-aging effects, with both plant- and human-derived melanin playing their important roles.Environmentally, microbial and plant-based melanin built a strong resilience in the elimination of heavy and toxic metals and compounds. In agriculture, microbial melanin is well known for improving soil health in addition to increasing plant tolerance to stress and shielding biocontrol chemicals from UV destruction and showing their high capacity and significant role in different industries, making it one of the most promising byproducts of the cellular process.SummaryMelanin, derived from different sources-microorganisms, plants, and humans-represents a flexible and sustainable biomaterial that is becoming increasingly important in the various fields. Its multifunctional qualities make it extraordinary application for use in food preservation, cosmetics, environmental improvement, and sustainable agriculture. This review summarizes melanin's potential for long-term innovation and industrial progress by amalgamating the ideas from several biological sources.

The growing demand for sustainable and environment-friendly materials has driven extensive research on biopolymers for applications in agriculture, food science, and environmental remediation. Among these, nanocellulose-hydrogel hybrids (NC-HHs) have gained significant attention as an innovative class of bio-based materials that uniquely combine the remarkable physicochemical properties of nanocellulose with the functional versatility of hydrogels. These hybrids are characterised by exceptional water retention, mechanical strength and biodegradability, enabling advances in precision agriculture, smart food preservation and contaminant remediation. This review provides a comprehensive understanding of the synthesis, properties, and multifunctional applications of NC-HHs, emphasising their innovative role in sustainability. In agriculture, NCHHs enhance soil moisture retention, support plant growth, and serve as carriers for controlled-release fertilizers, optimizing water and nutrient use efficiency. In the food industry, they enable intelligent packaging solutions that extend shelf life, monitor food freshness, and inhibit microbial growth. Additionally, NC-HHs present groundbreaking strategies for environmental remediation by effectively immobilizing pollutants in water and soil. Beyond summarizing recent advances, this review presents an in-depth mechanistic perspective on the interactions between NC and HH, critically evaluating their structure-property relationships, functional adaptability and application-specific performance. By integrating recent advances in nanocellulose functionalisation, polymer chemistry and the development of responsive hydrogels, this review critically examines the key technological innovations and future prospects of NC-HHs, underscoring their transformative potential in addressing global challenges related to food security, environmental sustainability, and sustainable agricultural practices.

Enhancing the catalytic activity of inorganic minerals is crucial for advancing wastewater treatment technologies. In this study, carbon and lab-scale minerals were combined to develop a novel carbon-based material, termed paired mineral carbon (PMC), using rice husk (RH) as the carbon source. Montmorillonite (MMt), goethite (GTt), and hybrid of goethite and MMt were utilized to prepare the PMC. The resulting material exhibited an increased specific surface area of 187 m2g-1, and demonstrated exceptional activation efficiency of peroxymonosulfate (PMS) for degrading diethyl phthalate (DEP). A pseudo-first-order kinetic constant (k1) of 0.923 min-1 was achieved at pH 6.0. Pairing minerals synergistically altered PMC's structure, which had the highest ID/IG ratio (0.87) indicative of abundant defective sites in its hierarchical porous structure. Reactive species such as SO4 center dot-, center dot OH, and 1O2 were identified as key contributors to DEP degradation through electron spin resonance (ESR) and quencher experiment. Density functional theory (DFT) calculations further revealed preferential radical attack on DEP at specific atomic sites (f0 values: 0.0837-0.1027). Furthermore, the lab-scale synthesized PMC costs $8.08 kg-1. More versatile than commercial activated carbon ($10 kg-1). The simple, adaptive, scalable synthesis optimizes industrial costs. Moreover, phytotoxicity assessment demonstrated that PMC/PMS treatment significantly reduced DEP toxicity, promoting healthier growth of Raphanus sativus and Zea mays seedlings. These findings highlight the potential of PMC as an eco-friendly, efficient and economical catalyst for advanced wastewater treatment, offering a sustainable approach to managing both chemical pollutant and herbicide phytotoxicity.

The widespread proliferation of water hyacinth (Eichhornia crassipes) in aquatic ecosystems has raised significant ecological, environmental, and socioeconomic concerns globally. These concerns include reduced biodiversity, impeded water transportation and recreational activities, damage to marine infrastructure, and obstructions in power generation dams and irrigation systems. This review critically evaluates the challenges posed by water hyacinth (WH) and investigates potential strategies for converting its biomass into value-added agricultural products, specifically nanonutrients-fortified, biochar-based, green fertilizer. The review examines various methods for producing functional nanobiochar and green fertilizer to enhance plant nutrient uptake and improve soil nutrient retention. These methods include slow or fast pyrolysis, gasification, laser ablation, arc discharge, or chemical precipitation used for producing biochar which can then be further reduced to nano-sized biochar through ball milling, a top-down approach. Through these means, utilization of WH-derived biomass in economically viable, eco-friendly, sustainable, precision-driven, and smart agricultural practices can be achieved. The positive socioeconomic impacts of repurposing this invasive aquatic plant are also discussed, including the prospects of a circular economy, job creation, reduced agricultural input costs, increased agricultural productivity, and sustainable environmental management. Utilizing WH for nanobiochar (or nano-enabled biochar) for green fertilizer production offers a promising strategy for waste management, environmental remediation, improvement of waterway transportation infrastructure, and agricultural sustainability. To underscore the importance of this work, a metadata analysis of literature carried out reveals that an insignificant of the body of research on WH and biochar have focused on the nano-fortification of WH biochar for fertilizer development. Therefore, this review aims to expand knowledge on the upcycling of non-food crop biomass, particularly using WH as feedstock, and provides crucial insights into a viable solution for mitigating the ecological impacts of this invasive species while enhancing agricultural productivity.