1. What is vegetal chitosan?

Chitosan is a natural biopolymer that is primarily derived from chitin, which is the second most abundant natural polysaccharide after cellulose. Chitin is commonly found in the exoskeletons of crustaceans like crabs, shrimps, and lobsters, as well as in the cell walls of certain fungi like mushroom, aspergillus niger.

Structure and Properties:

• Chemical Structure: Chitosan is obtained by deacetylating chitin. This process involves removing acetyl groups from chitin, resulting in a polymer that has free amine groups.
• Solubility: Unlike chitin, chitosan is soluble in acidic to neutral solutions, making it more versatile for various applications.
• Biocompatibility and Biodegradability: Chitosan is known for its excellent biocompatibility and biodegradability. It’s non-toxic and can be broken down by natural biological processes.

Chitosan, sometimes known as deacetylated chitin, is a natural polycationic linear polysaccharide derived from partial deacetylation of chitin. Chitin is the structural element in the exoskeleton of insects, crustaceans (mainly shrimps and crabs shell), and cell walls of fungi (oyster mushroom, agaricus bisprous and aspergillus niger), and also is the second most abundant natural polysaccharide after cellulose.

Chitosan, a natural polysaccharide prepared of fungal origin, is initially extracted and purified from reliable and abundant food or biotechnological fungal sources such as Agaricus bisporus or Aspergillus niger.

Chitosan is composed of glucosamine sugar units (deacetylated units) and N-acetyl-D-glucosamine units (acetylated units) interconnected by ß→(1.4) type linkages.

Uses and Applications:

1. Medical and Pharmaceutical Fields: Due to its biocompatibility and non-toxic nature, chitosan is used in wound healing, drug delivery systems, and as a biomaterial in tissue engineering.
2. Water Treatment: Its ability to bind with heavy metals and other contaminants makes it useful in water purification and treatment processes.
3. Agriculture: As a natural biostimulant and elicitor, chitosan is used to enhance plant growth and provide resistance against pathogens.
4. Food Industry: It’s used as a food additive for its antimicrobial properties, and as an edible film or coating to enhance the shelf life of perishable food products.
5. Cosmetics and Personal Care: In this realm, it finds use as a thickener, moisturizer, and film-forming agent, particularly in hair and skin care products.

Chitosan has been widely used in various fields, including wine, pharmaceuticals, dietary supplement, medicine, agriculture, and food industries, due to its biocompatibility, biodegradability, and non-toxicity. In recent years, researchers have investigated the use of vegetal chitosan, which is derived from fungal or plant sources, as a sustainable alternative for use in wine applications.

Variants:

• Traditional Chitosan: Traditionally sourced from marine crustaceans.
• Vegetal Chitosan: Derived from fungal sources, offering an alternative for those seeking non-animal derived products.

In summary, chitosan’s versatility, biodegradability, and non-toxic nature make it a valuable material across various industries, from healthcare to cosmetics. Its ability to be derived from non-animal sources also makes it an appealing option for vegetarian and vegan-friendly products.

2. What are the advantages of vegetal chitosan?

Vegetal chitosan, also known as fungal chitosan or mycelium chitosan, is a type of chitosan derived from the cell walls of fungi (mushroom and aspergillu niger). It has several advantages over traditional chitosan derived from shellfish, including:

• 1. Vegan and vegetarian-friendly: Vegetal chitosan is an excellent alternative for individuals who avoid animal-based products, such as those who follow a vegan or vegetarian lifestyle.
• 2. Allergen-free: Traditional chitosan is derived from shellfish, which can cause allergic reactions in some people. Vegetal chitosan does not contain any shellfish-derived ingredients, making it an allergen-free option.
• 3. Purer: Vegetal chitosan is often considered to be purer than traditional chitosan because it is derived from a single source, whereas traditional chitosan can be contaminated with other shellfish-related substances.
• 4. Better solubility: Vegetal chitosan is more soluble than traditional chitosan, which makes it easier to incorporate into various applications such as cosmetics, pharmaceuticals, wine and food.
• 5. Improved bioavailability: Some studies have suggested that vegetal chitosan has a higher bioavailability compared to traditional chitosan, which means that it can be absorbed and utilized more effectively by the body.

Overall, vegetal chitosan offers several advantages over traditional chitosan, making it an attractive alternative for individuals and industries looking for a vegan, allergen-free, and more effective chitosan source.

3. What are the benefits & functions of vegetal chitosan in PLA (Polylactic Acid) material?

Vegetal chitosan, sourced from mushrooms or fungi like Aspergillus niger, offers several interesting benefits and functions when incorporated into polylactic acid (PLA) materials. PLA is a biodegradable polymer derived from renewable sources such as corn starch or sugarcane, commonly used in bioplastics. Here’s how vegetal chitosan can enhance PLA:

Benefits of Vegetal Chitosan in PLA

1. Enhanced Biodegradability: Chitosan can accelerate the degradation process of PLA, making the composite more eco-friendly by improving its biodegradability in natural environments.

2. Natural Antimicrobial Properties: The inherent antimicrobial properties of chitosan help in preventing bacterial and fungal growth on PLA products, crucial for applications in medical devices and food packaging.

3. Improved Environmental Impact: Since both chitosan and PLA are derived from renewable resources, their combination contributes to reduced carbon footprint and less reliance on fossil-fuel-based polymers.

4. Improved Barrier Properties: Chitosan enhances PLA’s barrier properties against gases like oxygen and oils, essential for packaging applications to maintain the integrity and freshness of packaged goods.

Functions of Vegetal Chitosan in PLA

1. Mechanical Strength Enhancement: By integrating chitosan into PLA, the mechanical strength such as tensile strength and flexibility of the material can be significantly enhanced, which is advantageous for structural applications requiring robust materials.

2. Film Forming: Chitosan improves the film-forming capability of PLA, which is beneficial in applications that involve coating or creating thin films, such as in biodegradable films for agricultural uses.

3. Processing Aid: Chitosan can aid in the processing of PLA by improving its thermal stability and processability during manufacturing processes like extrusion and molding.

4. Compatibility Enhancer: Chitosan is compatible with PLA, and it helps in maintaining the integrity of the blend during the processing and usage of the composite material.

Incorporating vegetal chitosan into PLA materials thus opens up new avenues for developing biodegradable, antimicrobial, and mechanically robust materials suitable for a variety of industrial applications.

4. What are the forms of vegetal chitosan used in PLA material? and suitable applications?

Vegetal chitosan derived from sources like mushrooms and Aspergillus niger can be processed into various forms suitable for blending with PLA (Polylactic Acid). Here are the typical forms and their suitable applications, along with the addition of vegetal chitosan to PLA (Polylactic Acid), which can vary significantly depending on the desired properties and the specific application:

Forms of Vegetal Chitosan

1. Powder: Chitosan is commonly available in a fine powder form, which can be easily blended with PLA granules before extrusion. This form is versatile and can be used for uniform dispersion within the polymer matrix.
   • Adding Ratio: Generally, the addition of chitosan powder to PLA can range from 1% to 10% by weight. The exact percentage depends on the required mechanical properties and biodegradability.
   • Suitable Applications: This form is versatile and suitable for general-purpose bioplastic applications, including disposable items like cutlery, plates, and non-load-bearing items where moderate improvement in mechanical properties and biodegradability is beneficial.

2. Nanoparticles: Chitosan nanoparticles are used for more specialized applications. They provide a high surface area and can enhance the properties of PLA at a nano-scale, improving barrier properties and the mechanical strength of the composite material.
   • Adding Ratio: Chitosan nanoparticles are typically added in smaller quantities, often between 0.5% and 5% by weight. This is due to their high surface area and effectiveness in modifying properties at lower concentrations.
   • Suitable Applications: High-performance applications where enhanced barrier properties are needed, such as in precision medical devices, high-quality food packaging films, and coatings that require superior strength and microbial resistance.

3. Fibers: Chitosan fibers can be incorporated into PLA to create composite materials with enhanced structural integrity. These are particularly useful in applications requiring enhanced mechanical properties.
   • Adding Ratio: For fiber-reinforced composites, chitosan fiber content can vary widely from 5% to 30% by weight, depending on the desired tensile strength and flexibility.
   • Suitable Applications: Structural applications that require enhanced mechanical strength and durability, such as biodegradable pots for plants, structural panels in construction, and eco-friendly textiles.

4. Solution or Gel: Chitosan can be dissolved in certain solvents to form a solution or gel that can be mixed with PLA during the polymer processing, particularly in film casting or fiber spinning processes.
   • Adding Ratio: When used in a solution or gel form, chitosan is generally used at concentrations of about 1% to 3% in the solution, which is then mixed with PLA at varying ratios depending on the application.
   • Suitable Applications: Ideal for film casting and fiber spinning processes where uniform dispersion and coating are crucial. These applications include biodegradable films for agricultural use and medical textiles such as wound dressings that benefit from chitosan’s natural antimicrobial properties.

Suitable Applications

1. Medical Devices: Chitosan-PLA composites are highly suitable for medical applications due to their biocompatibility, biodegradability, and antimicrobial properties. Applications include surgical sutures, implants, and drug delivery systems.

2. Food Packaging: The antimicrobial and barrier properties of chitosan enhance PLA’s performance in food packaging. This can extend the shelf life of food products while maintaining food safety.

3. Agricultural Films: Chitosan-PLA films can be used in agriculture to create biodegradable mulch films. These films help in controlling soil temperature, preventing weed growth, and maintaining soil moisture without leaving harmful residues.

4. Textiles: Chitosan fibers blended with PLA can be used in the manufacture of biodegradable textiles, which are useful in both medical textiles (like bandages and gauze) and environmentally friendly clothing.

5. 3D Printing Filaments: The incorporation of chitosan into PLA filaments for 3D printing can enhance the printability and final properties of the printed objects, making them more suitable for specific applications like customized medical devices or biodegradable components.

These forms and applications demonstrate the flexibility and utility of chitosan when used in conjunction with PLA, making it a valuable material for a wide range of sustainable and high-performance applications.

Applications Based on Specific Properties:

• Enhanced Biodegradability: Lower concentrations (1%-3% powder or solution) in single-use products like packaging and disposable tableware.
• Mechanical Property Enhancement: Higher concentrations (up to 30% fibers) for structural applications requiring durability and strength.
• Antimicrobial and Barrier Enhancements: Mid-range concentrations (0.5%-5% nanoparticles) in medical and food packaging applications to leverage the antimicrobial and improved barrier properties without significantly compromising material flexibility and processability.

These guidelines help in choosing the right chitosan form and concentration for specific applications, ensuring the final product meets the required specifications and performance standards.

5. Which type of chitosan is suitable for each form of PLA?

The suitability of different types of chitosan for specific forms and applications in PLA (Polylactic Acid) depends on their chemical characteristics, such as viscosity, solubility, and molecular modification. Here’s a guide to which type of chitosan is most appropriate for each form of PLA, considering the viscosity range and specific chitosan derivatives:

1. Acid-Soluble Chitosan (Viscosity Range)

• 20-100cps: This lower viscosity chitosan is ideal for film applications where a smoother, more uniform dispersion is needed. It can be used in solutions or gels to produce thin, flexible films for packaging or agricultural films.
• 100-500cps: This medium viscosity is suitable for applications needing a balance between ease of processing and mechanical strength. It’s effective in general-purpose blending for items like disposable cutlery, where moderate improvements in mechanical properties are beneficial.
• 500-1000cps: Higher viscosity chitosan provides more substantial interactions within the PLA matrix, making it suitable for composites intended for structural applications where increased strength and stiffness are desired.

2. Chitosan Hydrochloride

• Suitable Form: Powder and nanoparticles. Chitosan hydrochloride is highly soluble in water, making it suitable for creating nanoparticle suspensions or fine powders that can easily be blended with PLA.
• Applications: Due to its excellent solubility and antimicrobial properties, it is ideal for medical devices and active packaging solutions that require high levels of microbial resistance.

3. Chitosan Oligosaccharide

• Suitable Form: Solution or gel. Chitosan oligosaccharides, being low molecular weight, dissolve well and are ideal for coating applications or incorporation into PLA as a solution.
• Applications: Particularly useful in coatings and films where antimicrobial properties are needed without significantly altering the mechanical properties of PLA. Suitable for food packaging and medical films.

4. Carboxymethyl Chitosan

• Suitable Form: Powder, solution, or fibers. Carboxymethyl chitosan is water-soluble and can modify the hydrophilicity of PLA composites.
• Applications: This derivative is excellent for applications requiring enhanced water resistance and stability, such as water-resistant textiles, wound care products, and environmentally sensitive applications where moisture management is critical.

General Guidelines for Application:

• Films and Coatings: Use lower viscosity acid-soluble chitosan or chitosan oligosaccharide for better film-forming capabilities and uniformity.
• Structural Components: Opt for higher viscosity acid-soluble chitosan to improve mechanical properties.
• Medical and Food Packaging: Chitosan hydrochloride and oligosaccharides are preferable for their soluble properties and antimicrobial effects, enhancing the safety and shelf life of products.

Choosing the right type of chitosan based on these properties ensures the enhanced performance of PLA in various applications, maximizing the benefits of this biodegradable composite.

6. What is the flowchart of vegetal chitosan processing?

The production process of plant chitosan is mainly obtained by extracting raw materials (mushrooms, Aspergillus niger), deproteinizing with dilute acid or alkali, deacetylating, drying, etc.

Here is a simplified flowchart of the production process of vegetal chitosan for your reference.

The flowchart of mushroom chitosan illustrates the process of producing chitosan and its derivatives from mushroom material. Here’s a summary of the key content:

1. Starting Material: The process begins with mushroom material as the source.
2. Filtration: The mushroom material undergoes a filtration process.
3. Protein Removal: Proteins are then removed from the filtered material using an alkali solution.
4. Ash Removal: Ash content is subsequently removed with acid.
5. Chitin Extraction:
   • Acid is added without bubbles to proceed to the next stage.
   • Chitin is extracted, which is not soluble in acid.
   • An acetylation step removes the acetyl groups from the chitin using sodium hydroxide (NaOH), converting it into chitosan, which is soluble in acid.
6. Drying: The acid-soluble chitosan is then dried to produce the final mushroom chitosan product, showcased as a white powder.
7. Chitosan Derivatives: Parallel to the drying process, there is a branch leading to the production of various chitosan derivatives:
   • Chitosan Hydrochloride: Chitosan converted into its hydrochloride form.
   • Enzyme Hydrolysis: Produces chitosan oligosaccharide through enzymatic hydrolysis.
   • Carboxymethyl Chitosan: Derived through the carboxymethylation of chitosan.

The flowchart depicts a methodical approach to converting mushroom material into various forms of chitosan, focusing on the purification and chemical modification steps necessary to achieve different chitosan-based products for use in various applications.

The flowchart of aspergillus niger chitosan outlines the process for extracting chitosan from Aspergillus niger, a type of fungus. Here’s a step-by-step summary of the key points:

1. Starting Material: Aspergillus niger is cultured through a fermentation process using corn.
2. Extraction:
   • The fungal biomass undergoes a bulk flocculation.
   • This is followed by centrifugation to separate the components.
   • The pH of the resulting material is adjusted to alkaline conditions (pH 8-10).
   • Another round of centrifugation and isolation occurs.
   • The pH is adjusted back to neutral (pH 7), and the sediment is washed and precipitated.
   • The sediment is then extracted with 5% acetic acid at 100°C for five hours to get the clear solution.
   • It is washed again to achieve a clear solution with a neutral pH.
3. Chitin Production:
   • The clear solution is treated with 7% sodium hydroxide (NaOH) at a ratio of 1:10 (W/V) at 50°C for three hours.
   • Centrifugal washing follows, resulting in the production of chitin as a clear solution to get the sediment.
4. Deacetylation:
   • The sediment undergoes the deacetylation process. It’s treated with 20% NaOH at a ratio of 1:10 (W/V) and heated in a microwave at 480W for 15 minutes.
   • This step is crucial to convert chitin into chitosan by removing acetyl groups.
5. Final Steps:
   • The final sediment, which is now deacetylated chitin or chitosan, is extracted.
   • It undergoes drying, followed by sieving to achieve the desired particle size.
6. End Product: The final product is solid Aspergillus niger chitosan.

This process includes several steps involving pH adjustment, centrifugation, chemical treatments, and heating, which are critical to ensuring the purity and quality of the chitosan extracted from Aspergillus niger.

7. In summary of vegetal chitosan in PLA (Polylactic Acid) material

Vegetal chitosan sourced from mushrooms and Aspergillus niger represents a compelling biopolymer for enhancing the properties of polylactic acid (PLA) materials, commonly used in biodegradable plastic applications.

Chitosan, a natural biopolymer derived from the chitin of these sources, is notable for its biocompatibility, biodegradability, and antimicrobial properties.

When integrated into PLA, vegetal chitosan not only improves the environmental profile of the composite by enhancing its biodegradability but also adds functional advantages like antimicrobial activity which is crucial for applications ranging from food packaging to medical implants.

This integration can be tailored in various forms, including powders, nanoparticles, or fibers, allowing for a broad range of applications and processing techniques.

The incorporation of chitosan from mushrooms and Aspergillus niger into PLA materials is particularly advantageous in terms of sustainability and performance.

As a renewable resource, vegetal chitosan supports the shift towards sustainable materials by reducing reliance on petroleum-based plastics and minimizing waste.

Moreover, its addition to PLA helps improve the mechanical and barrier properties of the final product, making it suitable for more demanding applications that require enhanced strength, durability, and resistance to microbial growth.

The versatility of chitosan-PLA composites, combined with their improved environmental and functional characteristics, positions them as an innovative solution in the realms of bioplastics, particularly appealing in sectors prioritizing eco-friendly and high-performance materials.