Introduction
Chitosan is a versatile natural biopolymer gaining increasing attention across biotechnology, pharmaceuticals, food processing, cosmetics, water treatment, and agricultural innovation. Derived primarily from marine shell sources, it combines biocompatibility, biodegradability, film-forming ability, and antimicrobial effects, making it a unique material capable of bridging scientific research and practical commercial application. This article explores what chitosan is, its source and production process, its physicochemical characteristics, key advantages, industry-specific applications, and its growing role in sustainable and environmentally responsible material solutions.
What is Chitosan?
Chitosan is a natural polysaccharide obtained by deacetylating chitin, which is the main structural material in the shells of shrimp, crab, and other crustaceans, as well as some fungi cell walls. From a structural point of view, chitosan is a linear copolymer composed of β-(1→4)-linked D-glucosamine (deacetylated units) and N-acetyl-D-glucosamine (acetylated units), and the ratio between these two units is usually described by the “degree of deacetylation” (DD). When the DD is higher, the polymer chain carries more free amino groups, which makes chitosan show a stronger cationic character and influences its solubility, reactivity, and interaction with other molecules.
Key physicochemical parameters
Degree of deacetylation (DDA)
Most chitosan falls in the 80–95% DDA range, with pharmaceutical and high‑performance grades often specified at about 85–92% or higher. Higher DDA generally improves solubility in dilute acids and increases cationic charge density, which enhances bioactivity, flocculation performance, and interaction with negatively charged molecules.
Viscosity grades
Chitosan is usually supplied as different viscosity grades measured in centipoise (cP) for a defined concentration and solvent system. Typical pharma and fine-chemical materials may span from low-viscosity grades around several tens of cP up to several hundred or about 800 cP, with custom viscosity tuning offered for formulation needs.
Solubility and particle size
Solubility behavior
Standard chitosan is insoluble in pure water and alkaline media but becomes soluble in dilute acidic solutions where the amino groups are protonated. Controlling DDA, molecular weight, and residual inorganic salts helps ensure rapid dissolution and stable, low‑turbidity solutions in customers’ processes.
Particle size (mesh)
Commercial grades are milled to specific mesh sizes (for example, 40–80 mesh, 80–120 mesh, or customized fine powders) so that they disperse and dissolve uniformly in acid media and blend consistently into solid formulations. Fine mesh products are preferred for pharmaceutical, cosmetic and high‑end coating applications, while coarser grades may be acceptable for agriculture or water treatment where rapid bulk hydration is more important than aesthetic appearance.
Impurities, microbiology, and safety
Inorganic and organic impurities
Typical specifications include limits for loss on drying, ash, protein content, and heavy metals such as lead, cadmium, mercury, and arsenic, which for pharmaceutical-grade materials are controlled to very low levels or “below detection limit” following pharmacopeial or elemental impurity guidelines. A clean impurity profile is essential for regulated markets and sensitive applications like injectables, wound dressings, and oral drug delivery systems.
Microbial limits
High-value grades specify total aerobic microbial counts, yeast and mold counts, and absence of specified pathogens in line with pharmacopeia or food regulations. For medical and pharmaceutical uses, additional controls on endotoxins and sometimes gamma irradiation or aseptic handling may be required to meet strict safety and sterility expectations.
The Natural Origin of Chitosan
Most commercial chitosan is obtained from chitin in the shells and exoskeletons of marine crustaceans such as shrimp, crab, lobster, krill, and related species. These shells are generated in large volumes as by‑products of seafood processing, so chitosan production helps convert what would otherwise be “waste” into a high‑value natural biopolymer.
In typical industrial practice, shell waste from shrimp or crab processing plants is collected, cleaned, and processed to isolate chitin, which is then chemically converted into chitosan by deacetylation. This creates a direct connection between chitosan and the sustainable utilization of marine resources, because the process adds value to an existing food‑industry side stream instead of requiring new biomass inputs.
Extraction & Production Process of Chitosan
Extraction and Purification of Chitin
Demineralization is the first step, which uses a dilute acid solution to remove a large amount of inorganic salts, such as calcium carbonate from the shell, which directly determines the ash content and purity of the final product.
Subsequently, deproteinization is carried out using a dilute alkaline solution for high-temperature treatment, with the aim of removing proteins attached to chitosan fibers, ensuring subsequent reaction efficiency, and improving the safety of the product in biomedical applications.
The final step is decolorization, which removes natural pigments and gives the product a commercially required white or off white powder appearance. After these steps, purified chitin can be obtained.
Deacetylation of chitin
The key to converting chitin into chitosan lies in the deacetylation reaction. This is achieved by hydrolyzing purified chitin in a high concentration, strong alkaline solution of sodium hydroxide at high temperature. This reaction aims to remove the acetyl groups from chitosan molecules, thereby generating free amino groups that endow chitosan with unique cationic properties.
Product Features & Advantages of Chitosan
Antimicrobial and antibacterial activity
Chitosan shows broad antimicrobial activity against many Gram‑positive and Gram‑negative bacteria, as well as fungi and yeasts, mainly because its positively charged amino groups interact with negatively charged microbial cell walls and membranes. This interaction can disturb membrane permeability, interfere with nutrient transport, and even affect DNA and protein synthesis, making it a natural candidate for food preservation coatings, hygiene products, and antimicrobial wound dressings.
Film-forming and barrier properties
In acidic solution, chitosan can be cast into clear, flexible films or coatings that adhere well to a wide range of substrates. These films provide oxygen and microbial barriers while remaining biodegradable and often edible, so they are widely explored in food packaging, fruit and vegetable coatings, cosmetic masks, and controlled‑release formulations.
Chelation and water treatment performance
Because of its amino and hydroxyl groups, chitosan is an efficient chelating and flocculating agent for many dissolved metal ions and negatively charged contaminants. This makes chitosan-based products valuable in industrial and municipal water treatment, where they help remove heavy metals, dyes, and suspended solids as a more sustainable alternative to purely synthetic flocculants.
Hemostatic capability and biocompatibility
Chitosan can promote rapid clot formation and support platelet adhesion, which underlies its use in hemostatic dressings and emergency bleeding‑control products. At the same time, its good biocompatibility and low toxicity have been demonstrated in many biomedical studies, supporting applications in wound healing, tissue engineering scaffolds, and drug‑delivery systems.
Biodegradability and advantage over synthetics
Chitosan is enzymatically degradable into harmless sugars in the environment and in living systems, which reduces long‑term residue concerns compared with many non‑degradable synthetic polymers. Combined with its natural origin from shell or fungal biomass and generally favorable safety profile, this biodegradability positions chitosan as a “green” functional polymer that helps brands and end users move toward more sustainable formulations without sacrificing performance.
Applications of Chitosan Across Industries
Biomedical and healthcare
In biomedical use, chitosan is incorporated into wound dressings, gauzes, and hemostatic pads where its antimicrobial and hemostatic properties help control bleeding and reduce infection risk while supporting moist wound healing. Hospitals, emergency kits, and military medical suppliers already purchase chitosan-based dressings for trauma care, burns, and chronic ulcers, so this is a well-established, real-world segment.
Chitosan is also widely researched and applied as a drug-delivery excipient, especially in oral, nasal, ocular, and transdermal systems, because its positive charge gives mucoadhesive properties and can enhance permeation of active ingredients. Pharmaceutical and biotech companies use chitosan to make nanoparticles, microspheres, hydrogels, and film coatings that provide controlled release, targeted delivery, and improved bioavailability of sensitive drugs.
Food preservation and nutrition
In the food industry, chitosan is used as an edible coating for fruits, vegetables, meat, and seafood to extend shelf life by forming a thin antimicrobial, oxygen-limiting film on the surface. Fresh produce packers and exporters apply chitosan coatings in post‑harvest lines to reduce microbial spoilage and moisture loss during cold-chain transport and retail display.
Chitosan is also used as a functional dietary fiber or nutraceutical ingredient in some beverages, tablets, and powders, leveraging its indigestible, positively charged polymer backbone. This allows brands to position products around digestive health, fat-binding, or cholesterol-management claims in markets where regulatory frameworks permit such positioning.
Water and wastewater treatment
Water treatment plants and industrial facilities use chitosan as a natural flocculant and adsorbent to remove suspended solids, dyes, and heavy metals from wastewater streams. Its amino and hydroxyl groups chelate metal ions like lead, copper, or chromium and help agglomerate colloidal particles into larger flocs that can be separated by sedimentation or filtration, providing a “greener” alternative to purely synthetic polymers.
Chitosan-based beads, membranes, and composite sorbents are implemented in plating, mining, textile, and dyeing industries where effluents contain both organic dyes and metal contaminants. This creates demand for technical-grade chitosan from engineering firms that design turnkey wastewater treatment systems for factories and municipalities.
Cosmetics and personal care
In cosmetics, chitosan functions as a film-forming, moisturizing, and conditioning polymer in skin-care gels, serums, masks, and hair-care products. Its cationic nature allows it to bind to negatively charged skin and hair surfaces, improving feel, smoothness, and hydration while stabilizing emulsions and suspensions in formulations.
Brands focused on “clean beauty” and natural ingredients use chitosan and its derivatives in products such as sheet masks, scalp tonics, and anti-acne gels, where antimicrobial and soothing properties are a marketing advantage. For these customers, non-animal or low-allergen grades and clear documentation of purity and origin are important selling points.
Agriculture and crop protection
In agriculture, chitosan is applied as a seed coating, foliar spray, or soil amendment to stimulate plant defense responses and improve stress tolerance. Seed companies and agrochemical formulators use chitosan to enhance germination, root development, and resistance against fungal pathogens, which can translate into better stand establishment and yield.
Chitosan-based formulations also serve as biocontrol agents and elicitors that trigger plant immunity, helping crops better cope with diseases, drought, and salinity while reducing reliance on conventional pesticides. This fits well with organic and sustainable farming programs that favor biologically derived inputs with low environmental impact.
Sustainability & Environmental Value of Chitosan
Renewable and circular raw materials
Chitosan is derived from chitin, which is mainly obtained from seafood-processing byproducts such as shrimp, crab, and other crustacean shells, as well as some fungal sources. Using these waste streams as raw materials reduces landfill pressure and transforms what was once a disposal problem into a renewable resource for high-value biopolymers.
Biodegradability and low environmental persistence
Chitosan is a biodegradable polymer that can be broken down by microorganisms into simple, non-toxic compounds such as carbon dioxide, water, and biomass, depending on the environment. In packaging, coating, and agricultural uses, this biodegradability allows chitosan films or residues to return safely to the environment after use.
Reducing reliance on synthetic polymers and chemicals
Because chitosan can act as a flocculant, adsorbent, film-former, thickener, and antimicrobial agent, it allows formulators to replace or reduce multiple synthetic additives in water treatment, packaging, agriculture, and personal-care products.
Why Choose Runtai Chemical as Your Chitosan Supplier
- Consistent Quality and Purity: Each batch of chitosan is manufactured under strict quality control with full documentation, including COA, MSDS, and analytical data.
- Customized Specifications: Tailored DDA levels, molecular weight ranges, viscosity grades, and particle sizes to meet the specific needs of different industries.
- Strong Technical Support: Our team provides formulation guidance, technical insights, and application recommendations for research and commercial use.
- Stable Supply Chain & Competitive Pricing: With secure sourcing and efficient logistics, we support stable long-term procurement and cost advantages for our customers.
- Compliance and Certifications: Chitosan meets international standards for safety and regulatory compliance, ensuring compatibility for global markets and applications.
Conclusion
Chitosan represents a unique bridge between natural resources and advanced material innovation. Its biodegradability, antimicrobial properties, biocompatibility, and functional versatility make it highly valuable across diverse sectors — from pharmaceuticals and biomedical research to water treatment, food preservation, cosmetics, and agricultural solutions. As global industries continue shifting toward sustainable and environmentally responsible materials, chitosan is poised to play an increasingly important role in future product development and industrial transformation.
With deep expertise, consistent supply quality, and strong customer support, Runtai Chemical is committed to helping partners worldwide unlock the full potential of chitosan. Whether you are sourcing for industrial manufacturing, R&D applications, or commercial product formulation, we provide reliable materials and technical guidance to support long-term success. Contact us to discuss your requirements, request samples, or obtain customized specifications tailored to your application needs.
