Lignin nanoparticles formation by multiscale structure control to regulate morphology and their adsorption, nucleation, and growth on chitin nanofibers.

The lignin nanoparticles (LNPs) synthesis relies on lignin polymers with heterogeneous molecules and properties, which impose significant limitations on the preparation and property regulation. The multiscale structure of lignin from monomers to oligomers, provides a potential pathway for precise regulation of its physical and chemical properties. The study addresses this challenge by employing coniferyl alcohol and sinapyl alcohol as monomers and separately utilizing the Zulaufverfaren (ZL) and Zutropfverfaren (ZT) methods to synthesize different types of lignin dehydrogenation polymers (DHPs) including guaiacyl (G)-ZL-DHP, G-ZT-DHP, syringyl (S)-ZL-DHP, and S-ZT-DHP. The investigation highlights the chemical bonds as essential components of lignin primary structure. Additionally, the secondary structure is influenced by branched and linear molecular structures. G unit provides some branching points, which are utilized and amplified in the ZL process of DHPs synthesis. The branched DHPs aggregate at the edge and form rod-like LNPs. While linear DHPs aggregate around the center, presenting polygonal LNPs. The study identifies that the branched LNPs, characterized by more surface charges and lower steric hindrance, can form a stable complex with chitin nanofibers. Emulsions with varying oil-to-water ratios were subsequently prepared, opening a new window for the application of LNPs in fields such as food and cosmetics.

Chitinase and Deacetylase-Based Chitin-Degrading Bacteria: One-Pot Cascade Bioconversion of Chitin to Chitooligosaccharides.

Cascade conversion of chitin into soluble and functional chitooligosaccharides has gained great attention. However, the biotransformation route is still limited to the low catalytic performances of chitin deacetylases (CDAs) and complicated procedures. In this study, a CDA from Arthrobacter sp. Jub115 (ArCDA) was identified and characterized, which showed a higher catalytic stability than the reported CDAs, with residual activity of 80.49%, 71.12%, and 56.09% after incubation at 30, 35, and 40 °C for 24 h, respectively. Additionally, ArCDA was identified to have a broad substrate spectrum toward ß-chitin and N-acetyl chitooligosaccharides. Moreover, an engineered chitin-degrading bacteria (CDB) with cell-surface-displayed deacetylase ArCDA and chitinase SaChiB was constructed to simplify catalysis procedures, facilitating the chitobiose production of 294.30 ± 16.43 mg/L in 10 h. This study not only identified a CDA with the desirable catalytic performance but also provided a strategy for constructing CDB, facilitating the high-value utilization of chitin.

An overview of the development of termite baits in the past 3 decades.

Since the commercialization in 1995, termite baits have been introduced in 32 countries, protecting over 3.7 million homes and reducing pesticide use by more than 11,100 metric tons. Over the past 3 decades, advancements have been made to address the limitations of bait systems, including improvements in bait toxicants, bait matrices, and the frequency of required site visits. Termite baits have been applied in both commercial and experimental area-wide projects. This article discusses the factors contributing to the success of these projects and the key elements driving the progress and advancements in termite bait technology.

Hydrothermal preparation of pharmaceuticals adsorbents from chitin and chitosan: Optimization and mechanism.

Hydrothermal treatment of fishery waste-derived chitin (CT) and chitosan (CS) was performed to prepare hydrochar adsorbents for the removal of pharmaceuticals of environmental concern. By systematically studying the effect of treatment conditions on the biochar structure, the correlation between hydrochar properties and the adsorption capacities was clarified to optimize the adsorption performance. CS hydrochars obtained by lower-temperature treatment showed high adsorption capacities for the pharmaceuticals having carboxyl groups attributed to the electrostatic binding. A decrease in the density of available amines in CS hydrochars prepared at higher temperatures resulted in lower adsorption capacities and the manifestation of different adsorption mechanisms based on hydrophobic and π-π interactions. CT hydrochars showed lower adsorption capacities than CS hydrochars due to inefficient carbonization and lack of adsorption sites. The hydrochar adsorbents prepared in this study address simultaneously the problems of marine waste bioresource utilization and environmental cleaning from the emergent pollutants.

A comprehensive review of chitosan-based functional materials: From history to specific applications.

Chitosan (CTS), a natural biopolymer derived from chitin, has garnered significant attention owing to its potential chemical, biological, and physical properties, such as biocompatibility, bioactivity, and biosafety. This comprehensive review traces the historical development of CTS-based materials and delves into their specific applications across various fields. The study highlights the evolution of CTS from its initial discovery to its current state, emphasizing key milestones and technological advancements that have expanded its utility. Despite the extensive research, the synthesis and functionalization of CTS to achieve desired properties for targeted applications remain a challenge. This review addresses current problems such as the scalability of production, consistency in quality, and the environmental impact of extraction and modification processes. Additionally, it explores the novel applications of CTS-based materials in biomedicine, agriculture, environmental protection, and food industry, showcasing innovative solutions and future potentials. By providing a detailed analysis of the current state of CTS research and identifying gaps in knowledge, this review offers a valuable resource for researchers and industry professionals. The novelty of this work lies in its holistic approach, combining historical context with a forward-looking perspective on emerging trends and potential breakthroughs in the field of CTS-based functional materials. Therefore, this review will be helpful for readers by summarizing recent advances and discussing prospects in CTS-based functional materials.

Identification, functional analysis of chitin-binding proteins and the association of its single nucleotide polymorphisms with Vibrio parahaemolyticus resistance in Penaeus vannamei.

Chitin-binding proteins (CBPs) play pivotal roles in numerous biological processes in arthropods, including growth, molting, reproduction, and immune defense. However, their function in the antibacterial immune defense of crustaceans remains relatively underexplored. In this study, twenty CBPs were identified and characterized in Penaeus vannamei. Expression profiling highlighted that the majority of CBPs were highly expressed in the intestine and hepatopancreas and responded to challenge by Vibrio parahaemolyticus. To explore the role of these CBPs in innate immunity, six CBPs (PvPrg4, PvKrtap16, PvPT-1a, PvPT-1b, PvExtensin and PvCP-AM1159) were selected for RNAi experiments. Silencing of only PvPrg4 and PvKrtap16 significantly decreased the cumulative mortality of V. parahaemolyticus-infected shrimp. Further studies demonstrated that inhibition of PvPrg4 and PvKrtap16 resulted in a marked upregulation of genes associated with the NF-κB and JAK-STAT signaling pathways, as well as antimicrobial peptides (AMPs), in both the intestine and hepatopancreas. These results collectively suggested that PvPrg4 and PvKrtap16 potentially promote V. parahaemolyticus invasion by negatively regulating the JAK-STAT and NF-κB pathways, thereby inhibiting the expression of AMPs. In addition, SNP analysis identified three SNPs in the exons of PvPrg4 that were significantly associated with tolerance to V. parahaemolyticus. Taken together, these findings are expected to assist in the molecular marker-assisted breeding of P. vannamei associated with anti-V. parahaemolyticus traits, as well as expand our understanding of CBP functions within the immune regulatory system of crustaceans.

Natural Feed Supplements From Crustacean Processing Side Streams for Improved Growth of Finfishes and Crustaceans: A Review.

Natural feed additives of plant/animal/microbial origin are researched as supplements in aquaculture to improve the properties of feed, minimize the usage of chemical alternatives, reduce food safety risks and ensure sustainability to combat global food and nutritional security. Side streams generated during shellfish processing possess valuable ingredients: protein, lipids, carotenoids, minerals and chitins. Considering the current trend of organic farming and antibiotic-free fish and shellfish, crustacean processing side streams and their derivatives seem promising and emerging resources as natural additives/supplements for formulating high-quality feeds with superior benefits. Lower concentrations of chitin and chitosan in diets are reported to stimulate the growth of shellfish and finfish under controlled conditions. Oligomers of chitosan and nano-chitosan are also the other potential derivatives as natural supplements in feed for better growth performance of aquaculture varieties. This review focuses on the significance of crustacean processing side streams and their derivatives, especially shrimp head meal, chitin, chitosan and chitosan oligosaccharides as potential natural additives in aquafeeds for promoting the growth performance of cultured fin fishes and shell fishes. Utilization in aquafeeds and the development of natural value-added supplements from crustacean processing side streams, especially shrimp head and shell leftover, offer an answer to the negative environmental impact due to its dumping; reduce the dependency on food fish for fish meal production & fishmeal for aquafeeds; solution to maintain the economic viability of the fish farmers & industry as well as to ensure the supply of safer and healthy aquatic foods to meet the objectives of sustainable development goals.

Differences in transcriptomic responses upon Phytophthora palmivora infection among cultivars reveal potential underlying resistant mechanisms in durian.

BACKGROUND: Phytophthora palmivora is a devastating oomycete pathogen in durian, one of the most economically important crops in Southeast Asia. The use of fungicides in Phytophthora management may not be a long-term solution because of emerging chemical resistance issues. It is crucial to develop Phytophthora-resistant durian cultivars, and information regarding the underlying resistance mechanisms is valuable for smart breeding programs. RESULTS: In this study, we conducted RNA sequencing (RNA-seq) to investigate early gene expression responses (at 8, 24, and 48 h) after the P. palmivora infection in three durian cultivars, which included one resistant cultivar (Puangmanee; PM) and two susceptible cultivars (Monthong; MT and Kradumthong; KD). We performed co-expression and differential gene expression analyses to capture gene expression patterns and identify the differentially expressed genes. The results showed that genes encoding heat shock proteins (HSPs) were upregulated in all infected durians. The expression levels of genes encoding HSPs, such as ERdj3B, were high only in infected PM. A higher level of P. palmivora resistance in PM appeared to be associated with higher expression levels of various genes encoding defense and chitin response proteins, such as lysM domain receptor-like kinases. MT had a lower resistance level than PM, although it possessed more upregulated genes during P. palmivora infection. Many photosynthetic and defense genes were upregulated in the infected MT, although their expression levels were lower than those in the infected PM. KD, the least resistant cultivar, showed downregulation of genes involved in cell wall organization or biogenesis during P. palmivora infection. CONCLUSIONS: Our results showed that the three durian cultivars exhibited significantly different gene expression patterns in response to P. palmivora infection. The upregulation of genes encoding HSPs was common in all studied durians. The high expression of genes encoding chitin response proteins likely contributed to P. palmivora resistance in durians. Durian susceptibility was associated with low basal expression of defense genes and downregulation of several cell wall-related genes. These findings enhance our understanding of durian resistance to Phytophthora infection and could be useful for the development of elite durian cultivars.

Water-in-water emulsions stabilized by nano-chitin.

A water-in-water (W/W) emulsion consists of microdroplets was formed by the spontaneous liquid-liquid separation by mixing polyacrylic acid and chitosan oligosaccharide in water, and these microdropletes were stabilized by nano-chitin, formed water-in-water Pickering emulsions. By taking the advantage of interfacial adsorption of nano-chitin, the W/W emulsion droplets composed of polyacrylic acid/chitosan oligosaccharide (COS/PAA) polyelectrolyte coacervate were successfully stabilized. Research results indicated that composite microspheres were formed by the nano-chitin stabilized COS/PAA emulsion, and the size of these composite microspheres was related to the concentration and morphology of the nano-chitin. As the concentration of nano-chitin increases, the size of the composite microspheres first increases and then decreases, gradually becoming more uniform; whereas a decrease in the length of nano-chitin will lead to an increase in the size of the composite microspheres. The formation of composite microspheres may be due to the electrostatic interactions between nano-chitin and the emulsion droplets. In addition, the composite microspheres exhibit the best release effect for berberine hydrochloride at a pH value of 3.

A Synbiotic Combining Chitin-Glucan and Lactobacillus acidophilus NCFM Induces a Colonic Molecular Signature Soothing Intestinal Pain and Inflammation in an Animal Model of IBS.

Chitin-glucan (CG) is a new generation of prebiotic. Lactobacillus acidophilus NCFM® (NCFM) is a probiotic with the ability to decrease abdominal pain. We evaluate the functional and molecular gastrointestinal responses to a synbiotic administration combining CG and NCFM in a rat model of long-lasting colon hypersensitivity. The intracolonic pressure was assessed during the 9-week experiment in animals receiving CG in association or not with NCFM and compared to that in Lacticaseibacillus paracasei Lpc-37®-treated animals and control rats receiving tap water. The effects of the synbiotic were evaluated using the Wallace score, the quantification of colon myeloperoxidase (MPO) and the master genes driving analgesia and inflammation. CG 1.5 alone and NCFM 109 colony forming units (CFU) alone similarly decreased the visceral pain sensitivity. Lpc-37 had no significant effect. The best profile of pain perception inhibition was obtained with the combination of CG 1.5 g and NCFM 109 CFU, confirming a synbiotic property. This synbiotic treatment significantly reduced macroscopic colonic lesions and MPO concentrations, and induced master genes involved in analgesia (CB1, CB2, MOR, PPARα), with a downregulation of inflammatory cytokines (IL-1ß, TNFα) and an induction of IL-10 and PPARγ. In conclusion, CG 1.5 g + NCFM 109 CFU significantly decreased visceral pain perception and intestinal inflammation through the regulation of master genes.

Structure-based virtual screening of novel chitin synthase inhibitors for the control of Phytophthora sojae.

BACKGROUND: Chitin synthase (CHS) is an important target for pesticide development as chitin biosynthesis is essential for the survival and reproduction of various organisms, such as oomycetes, fungi and insects. Small-molecule inhibitors of CHS have potential applications for the control of agricultural pests and diseases. RESULTS: In this study, exploiting the cryo-EM structures of PsChs1, the CHS indispensable to the sporangial production and virulence of soybean root rot pathogenic oomycete Phytophthora sojae, a virtual screening method combining by molecular docking, inhibitory activity measurement and biological activity determination was conducted, to identify novel small-molecule inhibitors of CHS. A chemical library containing ≈1.8 million compounds was screened, and four potent inhibitors (HS-20, HS-24, HS-36 and HS-40) were identified. Amongst these compounds, HS-20 showed the most potent inhibitory activity with a Ki value of 4.2 ± 0.2 µM. Besides inhibitory activities towards PsChs1, these compounds were effective in decreasing sporangial production and preventing zoospore infection. When inoculated with zoospores, HS-20 and HS-24 completely inhibited the growth of P. sojae, suggesting their potential in its prevention and control. CONCLUSION: This study identified four new compounds with potent chitin synthase (CHS) inhibitory activity, all of which significantly reduce sporangia production and zoospore infection. It also presents promising in silico techniques and small molecule candidates for the design and development of novel CHS inhibitors. © 2024 Society of Chemical Industry. Published by John Wiley & Sons Ltd.

Role of chitin synthases CHS1 and CHS2 in biosynthesis of the cyst wall of Cryptocaryon irritans.

Cryptocaryon irritans, a protozoan parasite that infects marine fish, is characterized by a complex life cycle that includes a cyst-forming reproductive phase. However, the composition of the cyst wall and mechanism of its formation remain unclear. In this study, we identified chitin as a key component of the cyst wall using calcofluor white and wheat germ agglutinin, with Fourier-transform infrared spectroscopy confirming its ß-form structure. Two chitin synthase genes, CHS1 and CHS2, were identified as being expressed throughout the life cycle and show close phylogenetic relationships with chitin synthase from ciliates. Incubation with specific anti-CHS1 and -CHS2 antibodies significantly reduced both the thickness and chitin content of the cyst wall, highlighting the critical role of these enzymes in chitin biosynthesis. Treatment with benzoylureas, which inhibit chitin synthesis, caused thinning of the cyst wall and downregulation of CHS gene expression, resulting in an 84 % reduction in the hatching rate after treatment with 0.01 mM CuSO4 compared with control tomonts. Western blot analysis demonstrated that recombinant CHS proteins are immunogenic, and tomonts from CHS-immunized grouper exhibited reduced size. These findings bridge a crucial knowledge gap in understanding of the C. irritans cyst wall and highlight promising targets for infection prevention and control strategies.

Efficacy of Food Industry By-Product ß-Glucan/Chitin-Chitosan on Lipid Profile of Overweight and Obese Individuals: Sustainability and Nutraceuticals.

Fat-binding nutraceutical supplements have gained considerable attention as potential cholesterol-lowering strategies to address dyslipidemia in overweight and obese individuals. This study aimed to evaluate the effects of a polysaccharide-rich compound containing ß-glucan/chitin-chitosan (ßGluCnCs) on lipid profiles and lipoprotein function. In a prospective, two-arm clinical trial, 58 overweight and obese individuals were randomized to receive either 3 g/day of ßGluCnCs or a placebo (microcrystalline cellulose) for 12 weeks. Serum lipids and lipoprotein functions were assessed at baseline and at 4-week intervals throughout the study. The administration of ßGluCnCs led to a significant increase in HDL cholesterol (HDLc) levels and improved HDLc/non-HDLc and HDLc/total cholesterol (TC) ratios, while reducing apolipoprotein B (ApoB) levels (p < 0.05). However, the intervention did not affect HDL particle diameter, particle number, or lipoprotein functionality. Women demonstrated greater sensitivity to changes in HDLc during ßGluCnCs supplementation, whereas men exhibited a significant reduction in ApoB levels. When stratified by baseline LDL cholesterol (LDLc) levels (cut-off: 130 mg/dL), the increase in HDLc and the ApoA1/ApoB ratio was found in the low-LDL group. In contrast, the high-LDL group experienced a significant reduction in atherogenic non-LDLc and LDLc, along with an improvement in HDL's antioxidant capacity after ßGluCnCs intervention. These changes were not statistically significant in the placebo group. In conclusion, our study demonstrated that daily supplementation with ßGluCnCs significantly improved lipid profiles, with effects that varied based on sex and baseline LDLc levels.

A Thermosensitive and Degradable Chitin-Based Hydrogel as a Brucellosis Vaccine Adjuvant.

Brucellosis is a zoonotic infectious disease that has long endangered the development of animal husbandry and human health. Currently, vaccination stands as the most efficacious method for preventing and managing brucellosis. Alum, as the most commonly used adjuvant for the brucellosis vaccine, has obvious disadvantages, such as the formation of granulomas and its non-degradability. Therefore, the aims of this study were to prepare an absorbable, injectable, and biocompatible hydroxypropyl chitin (HPCT) thermosensitive hydrogel and to evaluate its immunization efficacy as an adjuvant for Brucella antigens. Specifically, etherification modification of marine natural polysaccharide chitin was carried out to obtain a hydroxypropyl chitin. Rheological studies demonstrated the reversible temperature sensitivity of HPCT hydrogel. Notably, 5 mg/mL of bovine serum albumin can be loaded in HPCT hydrogels and released continuously for more than one week. Furthermore, the L929 cytotoxicity test and in vivo degradation test in rats proved that an HPCT hydrogel had good cytocompatibility and histocompatibility and can be degraded and absorbed in vivo. In mouse functional experiments, as adjuvants for Brucella antigens, an HPCT hydrogel showed better specific antibody expression levels and cytokine (Interleukin-4, Interferon-γ) expression levels than alum. Thus, we believe that HPCT hydrogels hold much promise in the development of adjuvants.

Biotransformation of insect processing residues: Production of lactic acid bacterial biomass and associated partial removal of proteins from chitin.

Processing of edible insects typically involves fractionating into high-value food ingredients, which results in by-products containing chitin and insoluble proteins. This study examined the effectiveness of lactic acid bacteria (LAB) in removing proteins from chitin in insect processing residues. Lesser mealworm processing residues were biologically treated for 48 and 120 h using LAB strains without added carbon sources. Results showed partial deproteinization, up to 29 % with Levilactobacillus brevis after 120 h. Most LAB grew up to 2 log10 colony-forming units/mL in the first 48 h. Confocal microscopy and Fourier-transform infrared spectra indicated that some protein remained attached to chitin. The molecular weight of solubilized proteins was affected by strain and time of incubation, with antioxidant activity increasing significantly after 120 h with Lacticaseibacillus paracasei. The biological treatment of insect processing streams can be a sustainable approach to producing high amounts of LAB biomass with subsequent protein solubilization and chitin release.

Evaluating the strategies to improve strength and water-resistance of chitin nanofibril assembled structures: Molecule-bridging, heat-treatment and deacidifying.

Chitin nanofibril (ChiNF) is a promising building block used to fabricate chitin fibers, films or gels via self-assembly from its aqueous suspension. Although mechanical strengthening of its assembled structures has made great advances, the unsatisfactory water-resistance is still a crucial obstacle to practical application and even rarely referred to. Herein, ChiNF was prepared via deacetylation-ultrasonication treatment and the strategies of molecule-bridging, heat-treatment and deacidifying that aiming to improve the strength and water-resistance of its assembled films were evaluated. Molecule-bridging, including tannic acid (TA) or/and chitosan (CS), improved the mechanical properties to some extent, but had no obvious positive effects on water-resistance; heat-treatment was a useful route to enhance both strength and water-resistance; interestingly, deacidifying was more efficient than heat-treatment with respect to improving strength and water-resistance, implying the presence of acid was the major reason for deteriorating assembled structures. Combining molecule-bridging, deacidifying and heat-treatment produced a strong ChiNF-TA/CS cast film with excellent water-resistance. Different from the commonly-used approach of vacuum filtration, these strategies are very suitable for large-scale production of the ChiNF-based self-supported films or coatings via solution casting. Furthermore, the reverse dialysis deacidification simultaneously produced highly concentrated suspensions suitable for dry-spinning, and thus strong chitin macrofibers were successfully fabricated.

Nature's loom: How to design a spinning tool using chitin-protein based composite material.

Silk-producing animals use spigots to generate natural silk fibers for various purposes. These natural looms must be able to withstand prolonged silk extrusion. To gain insight into the functional basis of spigots, we report on the structural design of the spigot of the silkworm Bombyx mori. The B. mori spigot exhibits a unique triple-ridged strip surface structure, consisting of cuticle proteins, resilin, chitin, and metal ions (such as K and Ca). This multi-microstructure endows the spigot with superior hierarchical mechanical properties, enabling it to function as a spinning tool for silk formation, thereby influencing the structure and performance of the silk. These findings demonstrate new pathways for achieving specialized functions in confined spaces, providing theoretical support for understanding the natural spinning mechanism and inspiring new directions for developing innovative biomimetic materials.

Turning black soldier fly rearing by-products into valuable materials: Valorisation through chitin and chitin nanocrystals production.

The industry of insect-based proteins as feed and food products has been encountering a huge development since the last decade, and industrial-scale factories are now arising worldwide. Among all the species studied, Black Soldier Fly is one of the most promising and farmed. This rearing activity generates several by-products in the form of chitin-rich biomass that can be valorised to keep a virtuous production cycle embedded in the scope of the bioeconomy. Herein, we report the isolation of chitin and, for the first time, chitin nanocrystals (ChNCs) from all the BSF rearing by-products, i.e., moults (larval exuviae, puparium) and dead adults. Extraction yields, were dependent on the type of by-products and ranged from 5.8 % to 20.0 %, and the chemical structure of the extracts exhibited typical features of α-chitin, confirmed by FTIR, NMR, XRD and TGA analysis. Both STEM in SEM and AFM analysis confirmed the isolation of chitin nanocrystals presenting a rod-like morphology. The average nanocrystal height estimated by AFM ranged from 13 to 27 nm depending on the by-product sample. The following results highlighted the potential of BSF rearing by-products, promoting an approach to valorise those industrial waste and paving the way towards insect-based biorefinery.

Valorization of fishery industry waste: Chitosan extraction and its application in the industry.

Waste from the fishing industry is disposed of in soils and oceans, causing environmental damage. However, it is also a source of valuable compounds such as chitin. Although chitin is the second most abundant polymer in nature, its use in industry is limited due to the lack of standardized and scalable extraction methods and its poor solubility. The deacetylation process increases its potential applications by enabling the recovery of chitosan, which is soluble in dilute acidic solutions. Chitosan is a polymer of great importance due to its biocompatible and bioactive properties, which include antimicrobial and antioxidant capabilities. Chitin extraction and its deacetylation to obtain chitosan are typically performed using chemical processes that involve large amounts of strongly acidic and alkaline solutions. To reduce the environmental impact of this process, extraction methods based on biotechnological tools, such as fermentation and chitin deacetylase, as well as emerging technologies, have been proposed. These extraction methods have demonstrated the potential to reduce or even avoid using strong solvents and shorten extraction time, thereby reducing costs. Nevertheless, it is important to address existing gaps in this area, such as the requirements for large-scale implementation and the determination of the stoichiometric ratios for each process. This review highlights the use of biotechnological tools and emerging technologies for chitin extraction and chitosan production. These approaches truly minimize environmental impact, reduce the use of strong solvents, and shorten extraction time. They are a reliable alternative to fishery waste valorization, lowering costs; however, addressing the critical gaps for their large-scale implementation remains challenging.

Advances in extraction, utilization, and development of chitin/chitosan and its derivatives from shrimp shell waste.

Shrimp consumption is in great demand among the seafood used globally. However, this expansion has resulted in the substantial generation and disposal of shrimp shell waste. Through literature search, it has been observed that since 2020, global scholars have shown unprecedented interest in shrimp shell waste and its chitin/chitosan. However, these new insights lack corresponding and comprehensive summarization and analysis. Therefore, this article provides a detailed review of the extraction methods, applications, and the latest research developments on chitin/chitosan from shrimp shells, including micro-nano derivatives, from 2020 to the present. The results indicate that chemical extraction remains the primary technique for the extraction and preparation of chitin/chitosan from shrimp shells. With further refinement and development, adjusting parameters in the chemical extraction process or employing auxiliary techniques such as microwave and radiation enable the customization of target products with different characteristics (e.g., deacetylation degree, molecular weight, and degree of acetylation) according to specific needs. Additionally, in pursuit of environmentally friendly, efficient, and gentle extraction processes, recent research has shifted toward microbial fermentation and green solvent methods for chitin/chitosan extraction. Beyond the traditional antibacterial, film-forming, and encapsulation functionalities, research into the applications of chitosan in biomedical, food processing, new materials, water treatment, and adsorption fields is gradually deepening. Chitin/chitosan derivatives and their modified products have also been a focal point of research in recent years. However, with the rapid expansion, the future development of chitin/chitosan and its derivatives still faces challenges related to the unclear mechanism of action and the complexities associated with industrial scale-up.