Search Results (80)

Chitin, one of the most abundant natural polysaccharides, has gained increasing attention for its structural diversity and potential in biomedicine, agriculture, food packaging, and advanced materials. Conventional chitin production from crustacean shell waste faces limitations, including seasonal availability, allergenic protein contamination, heavy metal residues, and environmentally harmful demineralization processes. Chitin from fungi and microalgae provides a sustainable and chemically versatile alternative. Fungal chitin, generally present in the α-polymorph, is embedded in a chitin–glucan–protein matrix that ensures high crystallinity, mechanical stability, and compatibility for biomedical applications. Microalgal β-chitin, particularly from diatoms, is secreted as high-aspect-ratio microrods and nanofibrils with parallel chain packing, providing enhanced reactivity and structural integrity that are highly attractive for functional materials. Recent progress in green extraction technologies, including enzymatic treatments, ionic liquids, and deep eutectic solvents, enables the recovery of chitin with reduced environmental burden while preserving its native morphology. By integrating sustainable sources with environmentally friendly processing methods, fungal and microalgal chitin offer unique structural polymorphs and tunable properties, positioning them as a promising alternative to crustacean-derived chitin. Full article

Chitosan, a naturally abundant and biodegradable biopolymer derived from chitin found in crustacean shells, has emerged as a promising material for addressing environmental challenges. Its reactive amino and hydroxyl groups enable diverse interaction mechanisms. This makes it effective for removing heavy metals, dyes, pharmaceuticals, and other contaminants from water. However, the limitations of native chitosan, such as poor solubility and mechanical strength, necessitate strategic modifications. This review comprehensively examines recent advances in chitosan derivatives and composites. It focuses on modern modification strategies, such as chemical, physical, and composite formation, that enhance stability, selectivity, and efficiency. It explores the design principles of high-performance composites. It also details the multifaceted mechanisms of pollutant removal, including adsorption, catalysis, membrane filtration, and flocculation. Critical practical challenges are critically assessed. These include scalability, regeneration, lifecycle sustainability, and real-world implementation. Furthermore, emerging trends are highlighted. These integrate circular economy principles, seafood waste valorization, and digital optimization through the use of artificial intelligence. By consolidating current knowledge, this review aims to bridge the gap between laboratory innovations and large-scale environmental applications. It guides the development of intelligent, scalable, and ecologically responsible solutions based on this remarkable biopolymer. Full article

Chitosan films are promising for food packaging but are limited by poor solubility, weak mechanical strength, and insufficient functional properties. Most conventional chitosan is derived from crustacean shells, with limited exploration of alternative biosources. To overcome these drawbacks, this study utilized silkworm pupae chitosan as a substrate and graft-modified it with gallic acid (GA-g-CS) to develop functional composite films for blueberry preservation. The results showed that the synthesized GA-g-CS exhibited a grafting efficiency of 83.8%. Compared to chitosan films, the GA-g-CS composite films showed enhanced physical properties, mechanical properties, UV-blocking capacity, antioxidant activity, and antimicrobial activity. Water solubility increased by 21%, and water vapor permeability was reduced by approximately 91%. In blueberry preservation trials, GA-g-CS composite films reduced weight loss by 12%, decreased decay incidence by 30%, and better maintained firmness and nutritional content. This study modified silkworm pupae-derived chitosan to overcome the inherent limitations of native chitosan. The resulting GA-g-CS film represents a high-performance active packaging material with significant potential. The resulting GA-g-CS film represents a high-performance active packaging material with potential for preserving perishable foods prone to oxidation and spoilage. Full article

Aquatic biomass—ranging from fish scales and crustacean shells to various algae species—offers an abundant, renewable source for carbon dot (CD) synthesis, aligning with circular economy principles. This review highlights recent studies for valorizing aquatic biomass into high-performance carbon-based nanomaterials—specifically aquatic biomass-based carbon dots (AB-CDs)—briefly summarizing green synthesis approaches (e.g., hydrothermal carbonization, pyrolysis, and microwave-assisted treatments) that minimize environmental impact. Subsequent sections highlight the varied applications of AB-CDs, particularly in biosensing (including the detection of marine biotoxins), environmental monitoring of water pollutants, and drug delivery systems. Physically AB-CDs show unique optical and physicochemical properties—tunable fluorescence, high quantum yields, enhanced sensitivity, selectivity, and surface bio-functionalization—that make them ideal for a wide array of applications. Overall, the discussion underlines the significance of this approach; indeed, transforming aquatic biomass into carbon dots can contribute to sustainable nanotechnology, offering eco-friendly solutions in sensing, environmental monitoring, and therapeutics. Finally, current challenges and future research directions are discussed to give a perspective of the potential of AB-CDs; the final aim is their integration into multifunctional, real-time monitoring and therapeutic systems—for sustainable nanotechnology innovations. Full article

In this paper, mussel shells were used to produce chitin, chitosan, and calcium acetate using chemical processes, searching for an alternative environmentally friendly biopolymer and calcium source. Mussel shells were treated with acetic acid as a demineralizing agent, resulting in separate solid fractions and calcium solution. The solid was further purified to produce chitin by deproteinization and decolorization processes, and then the deacetylation process was used to obtain chitosan. The calcium solution was evaporated to produce calcium acetate powder. The yields of extracted chitin, chitosan, and calcium acetate from 100 g of mussel shells were 2.98, 2.70, and 165.23 g, respectively. The prepared chitin, chitosan, and calcium acetate were analyzed by Fourier transform infrared (FTIR) spectrophotometry, X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscope (SEM) to confirm the chemical and physical properties. The analysis results of chitin and chitosan revealed the similarity to chitosan derived from crustaceans and insects in terms of functional group, structure and morphologies. The prepared calcium acetate shows FTIR and XRD data corresponding to calcium acetate monohydrate (Ca(CH₃COO)₂·H₂O) similar to synthesized calcium acetate in previous research. In addition, the mineral contents of calcium acetate identified by X-ray fluorescence (XRF) analysis exhibit 97.8% CaO with non-toxic impurities. This work demonstrated the potential of the production process of chitin, chitosan, and calcium acetate for the development of a sustainable industrial process with competitive functional performance against the commercial chitin and chitosan production process using crustacean shells and supported the implementation of a circular economy. Full article

Machine vision/image analysis is used in the sorting and handling of many aquatic species. Pictures of 474 New Zealand Greenshell™ (Perna canaliculus, Gmelin, 1791) whole unopened mussels (215 females and 259 males) from the top and from the side were analyzed to evaluate if visual attributes (size, shape, and color) can be used to differentiate gender. Size (length, width, height, and view area), color, and shape (by elliptic Fourier analysis and by ray length-ray angle analysis) were analyzed and differences by gender tested. Application of Artificial Neural Networks (ANN), Principal Component Analysis (PCA), Canonical Discriminant Analysis (CDA), and Random Forest (RF) to the shape parameters failed to reliably predict gender. Comprehensive morphometric and color characterization of males and females, as well as shape parameters, are presented as a reference for future image-based research. The parasitic crustacean pea crab can change the shape of mussel shells, and elliptic Fourier analysis can quantify this difference. Full article

We studied the feeding habits of the common eagle ray (Myliobatis aquila) in the shallow northern Adriatic Sea. Altogether we analysed the contents of 122 stomachs of specimens caught as by-catch in the Gulf of Trieste and along the west Istrian coast. Shelled molluscs (N% = 75.17), mainly bivalves and gastropods, were the most prominent prey categories, while crustaceans, sipunculids, echinoderms and polychaets (N% < 10) represented considerably smaller numbers. With increasing size (and age) the eagle rays tend to become more experienced in preying molluscs and specialized to this prey category. The obtained results are in general in agreement with the limited existing reports on the diet of the common eagle ray in the Mediterranean Sea and adjacent areas. Full article

Seafood waste is often landfilled and/or discarded into water, raising microbiological pollution and environment policy concerns. Repurposing this low-cost biomass collected at point-source processing centers can help reduce greenhouse gas emissions and support industrial progress in developing economies. Safe alternative methods to utilize seafood waste were investigated. Hydrothermal carbonization-enriched shrimp shell waste was converted into higher-value products, such as sprayable fertilizer and dry biochar fertilizer pellets. Environment friendly sprayable fertilizer from shrimp and crab shell waste as an inexpensive carbon fixer is a potential solution. An average spray coverage area of 0.12 m² from only 300 mL of 1:10 shrimp shell waste to water mixture is reported. Characterization using N:P:K ratios from elemental analysis showed crustacean shell waste to comprise long-term organic carbon fixers in the soil with minor mineral enrichment, demonstrating potential for long-term soil care. Additionally, hydrothermally carbonized mineral rich shrimp shell and untreated crab shell waste were pelletized to test their friability and feasibility in transportation. Such a bio-investigation to promote economic goals for sustainability can improve biomass waste handling locally. Full article

Antimicrobial resistance (AMR) is a major global health problem, exacerbated by the excessive and inappropriate use of antibiotics in human medicine, animal care and agriculture. Therefore, new strategies and compounds are needed to overcome this issue. In this view, it may be appropriate to reconsider existing biomaterials to alleviate antibiotic overuse. Chitin, a naturally abundant amino mucopolysaccharide, is a poly-β-1, 4-N-acetylglucosamine (GlcNAc). It is a white, hard, inelastic, nitrogenous polysaccharide and the major source of surface pollution in coastal areas. Chitosan derives from the partial N-deacetylation of chitin and originates from the shells of crustaceans and the fungi cell walls. It is a nontoxic natural antimicrobial polymer approved by GRAS (Generally Recognized as Safe by the United States Food and Drug Administration). Chitin and chitosan, as non-toxic biopolymers, are useful compounds for wastewater treatment to remove pollutants, such as pharmaceuticals, heavy metals and dyes. The described features make these biopolymers intriguing compounds to be investigated for their application as antibacterials. Full article

Ocean acidification (OA) associated with climate change is expected to lower the ocean’s pH by 0.5 units by 2100. Whilst associated effects such as coral bleaching and shell calcification are well documented, lesser-known impacts are the ‘invisible’ effects on animal sensory systems. Olfactory disruption impacts the behaviour towards chemical cues in many marine species, including crustaceans. We examine the effects of microplastic odour and additional stressors on the European green crab C. maenas. Using uridine diphosphate (UDP) and uridine triphosphate (UTP) as a sex pheromone bouquet, glutathione (GSH) as a food cue, and polyethylene (PE) as plastic odour, cues were mixed with carboxycellulose to create slow-release gels. Crabs were exposed to gels in seawater pH values of 8.2, 7.6, and 7.2. Crabs took longer to react to all odours in reduced pH conditions (pH 8.2 to pH 7.2, p = 0.0017). At a low pH, PE-exposed crabs exhibited attraction towards microplastic odour and changed behavioural responses by burying. The study confirms low pH as disruptive to olfaction and highlights that plastic derivatives can become more bioactive at reduced pH levels, potentially increasing the threat posed by microplastic pollution. Further research is required to determine the potential long-term impacts of the combined threat of microplastics and reduced pH in the environment. Full article

Semicarbazide (SEM), a metabolite of nitrofurazone (NFZ), is widely used to detect the illegal application of NFZ in crustaceans. The conventional detection method involves chemical derivatization combined with reversed-phase liquid chromatography–tandem mass spectrometry (RPLC-MS/MS), which is both complex and time-consuming. To address this limitation, a more efficient approach was developed for SEM detection. This study introduces a modified QuEChERS pretreatment method coupled with hydrophilic interaction liquid chromatography–tandem mass spectrometry (HILIC-MS/MS) for detecting SEM in crustaceans. The proposed method is simple, fast, and highly accurate, making it universally applicable for SEM detection in crustaceans. Additionally, the method was applied to investigate NFZ metabolism in Macrobrachium rosenbergii with a kinetic model. The findings suggested a plausible mechanism for the absorption of NFZ and its subsequent transfer from meat to the shell. In conclusion, this study provides a simple and rapid technique for SEM detection in crustaceans with immense application value. Full article

The red king crab, Paralithodes camtscaticus, is a commercially significant crustacean that supports lucrative fisheries in Russia, the USA, and Norway. The western Kamchatka shelf, located in the Sea of Okhotsk, is home to one of the most important populations of the red king crab. In this study, we have conducted a review of the symbionts associated with P. camtscaticus in the waters off the Kamchatka Peninsula. A total of 42 symbiotic species belonging to 14 different phyla were identified in association with the red king crab. Out of these, 14 species were found to be parasitic to the red king crab, while the remaining 28 were either commensal or epibiont in nature. The taxa with the highest number of associated species included ciliates (11), crustaceans (8), and acanthocephalans (4). Our study found that red king crabs suffering from shell disease exhibited a more diverse symbiotic fauna and higher infestation indices as compared to healthy crabs, which were found to be free from parasites. Dangerous symbionts, such as dinoflagellates Hematodinium sp. and rhizocephalan barnacles Briarosaccus callosus, had low incidence rates, indicating that the red king crab population in the Sea of Okhotsk is in good condition with respect to population abundance, health, and recruitment and is not being adversely impacted by symbiotic organisms. Full article

This study presents the first comprehensive data on a vermetid formation along the Apulian coast of the Adriatic Sea, representing one of the northernmost records in the Mediterranean. Surveys along the Brindisi coastline employed visual inspection to map the bioconstruction’s distribution and extension. Detailed data on the bioconstruction inner and the outer edge length, thickness, width, slope and topographic complexity were collected at three selected sites. Moreover, photographic replicates were used to assess shell aperture density and diameters of Dendropoma sp. Associated fauna was studied using two quantitative sampling squares in each transect. The results showed that the vermetid bioconstruction consisted of a thin, encrusted monolayer (thickness < 1.5 cm) that extended for 3.273 linear kilometers, covering 17.23% of the investigated area; it had an average width of 0.5 m, with a mean density of Dendropoma sp. at 2.52 ind/cm². The associated fauna was composed of 47 taxa dominated by crustaceans, mollusks and annelids. Species richness was correlated with the bioconstruction’s thickness and complexity. These findings underline the ecological importance of vermetid bioconstructions as biodiversity hotspots. The lack of massive mortality events along the Apulian coast, in contrast to other Mediterranean vermetid bioconstructions, underscores the necessity for targeted conservation measures. Full article

Eriocheir sinensis is an important and popular crustacean species in China, producing huge economic benefits. Large individuals of E. sinensis are preferred due to market demand. The long-term goal of our research group is to produce a new variety of E. sinensis with better growth performance and stronger abilities to resist environmental changes through mass selection. The present study aimed to evaluate the progress of the genetic breeding of E. sinensis by analyzing the genetic diversity and genetic distance between the basic breeding population (pooled population of Suqian and Yixing, G0) and generation 1 (G1) using whole-genome sequencing (WGS). The growth traits, including body weight, shell length, shell width, and third appendage length, in the G1 generation increased by 8.3%, 7.9%, 9.6%, and 9.3%, respectively, compared with those of the G0 generation, indicating that the G1 generation showed better growth performance. A total of 372,448,393 high-quality single nucleotide polymorphisms (SNPs) were detected in 40 E. sinensis individuals, with an average of 9,331,209.83 SNPs. The fixation index values were 0.007 between the Yixing and Suqian populations and 0.015 between the G0 generation and G1 generation, indicating a close genetic background between these groups, especially when considered in combination with the phylogenetic tree and principal component analysis. All of these data suggest that genetic information was stably inherited by the G1 generation, with no introduction of foreign genetic information during the genetic breeding process. In addition, the genetic diversity analysis revealed that the G0 and G1 generations showed a high level of genetic diversity and a relatively stable genetic structure. The present study evaluated the recent progress of the genetic improvement of E. sinensis by our research group, providing valuable evidence for further genetic improvement in this species. Future studies will be performed to select growth-related SNPs and genes through genome-wide association studies. Full article

Soil pollution by heavy metals (HMs) is a major environmental problem around the world. The addition of biowaste-based stabilizers for HM remediation has recently gained attention due to its relatively low cost and eco-risk, abundance, ease of operation, and quick remediation results. Among these stabilizers, shell (crustacean shell, bivalve shell, and eggshell), starfish, and bone-based stabilizers are particularly attractive because of their high Ca and P contents, allowing for highly efficient HM immobilization and simultaneous supplement of nutrients to the soil. However, a comprehensive review focusing on these stabilizers is currently missing. Therefore, this review attempts to summarize the HM immobilization efficiency of these stabilizers and the mechanisms associated with HM stabilization, and perform an operation cost estimation and cost comparison. Cost comparisons among different stabilizers are widely ignored in reviews due to the lack of reliable cost estimation tools or methods. However, for practical application in soil remediation, cost is one of the most important factors to consider. Thus, a simple but reasonable cost estimation method is developed and discussed in this review. Bivalve shell-based stabilizers demonstrated the most promising results for the immobilization of soil HMs in terms of higher performance and lower cost. Current research limitations, challenges, and recommendations regarding possible future research directions are also provided. Full article