Introduction to bacterial cellulose

Bacterial Cellulose (BC) , is a high-purity cellulose secreted by specific bacteria during culture. Bacterial cellulose has unique structure and excellent properties, and is widely used in various fields. The following is a detailed introduction to bacterial cellulose:

• Preparation method

1. Media preparation: Commonly used media include Hestrin-Schramm ( HS ) media, synthetic media and various improved media. These media contain nutrients such as glucose or other carbon sources, nitrogen sources, minerals, etc.

2. Inoculation and fermentation: Inoculate cellulose-producing bacteria such as Komagataeibacter xylinus into liquid culture medium and ferment at appropriate temperatures (usually 25-30°C ) and conditions (such as standing or shaking culture).

3. Formation and collection of cellulose: During the fermentation process, cellulose secreted by bacteria forms a transparent or translucent film on the liquid surface. After a period of culture, the thickness of the cellulose film gradually increases.

4. Purification: Remove the resulting cellulose film from the culture medium, remove bacteria and other impurities by alkali treatment (such as treatment with NaOH solution), and then wash repeatedly with deionized water until the washing solution is colorless and transparent.

• Physical characteristics

1. Structure: Bacterial cellulose is composed of nano-scale fiber networks, with fiber diameters usually between 20-100 nanometers and has a highly pure three-dimensional network structure.

2. Purity: Bacterial cellulose contains almost no lignin and hemicellulose, and is extremely purified.

3. Crystallinity: It has high crystallinity, and its main crystal form is cellulose I.

4. Specific surface area: Due to its nanoscale network structure, bacterial cellulose has a very high specific surface area.

• Performance and Advantages

1. Mechanical properties: Bacterial cellulose has excellent mechanical strength and elastic modulus.

2. Biocompatibility and biodegradability: purely natural, non-toxic, good biocompatibility and biodegradability, suitable for biomedical materials.

3. High water absorption: It can absorb and retain a large amount of water, which is conducive to wound healing and drug release.

4. Transparency and optical properties: Bacterial cellulose film has high transparency and can be used in optical devices and display materials.

5. Thermal stability: It has good thermal stability and can maintain a stable structure at a higher temperature.

• Application areas

1. Medical materials:

Wound dressing: Bacterial cellulose is highly absorbent and biocompatible and can be used to prepare high-performance wound dressings to promote wound healing.

Tissue Engineering: As a tissue engineering scaffold material, it is used for the regeneration of tissues such as skin, cartilage, etc.

Drug delivery: used to prepare drug delivery systems to control drug release rate.

2. Food and beverages:

Food additives: Bacterial cellulose is used as a thickener and stabilizer in a variety of foods and beverages.

Artificial meat: In artificial meat production, it is used to simulate the texture and taste of meat.

3. Industrial application:

Papermaking and textile: As an additive, enhances the performance of paper and textiles.

Composite materials: used to enhance polymer-based composite materials and improve their mechanical properties.

4. Electronics and Optical Devices:

Flexible electronics: used to prepare flexible displays and sensors.

Optical film: Due to its high transparency and excellent optical properties, bacterial cellulose can be used to make optical films and devices.

• Prospects and Challenges

1. Production cost: The cost of large-scale production of bacterial cellulose is relatively high, and it is necessary to optimize culture conditions and improve production efficiency.

2. Yield and purity control: More effective culture and purification methods are needed to ensure high yield and high purity.

3. Application development: It is necessary to further study and develop the specific application of bacterial cellulose in different fields to broaden its application scope.

In short, bacterial cellulose has become a hot spot in scientific research and industrial applications due to its unique properties and wide application potential. With the continuous advancement of technology, its application areas will continue to expand.