Fermentation method for preparation of nanocellulose: Creating high-purity biological materials from the perspective of microorganisms

Among the various preparation methods of nanocellulose , the Fermentation Method has attracted widespread attention due to its advantages such as green and environmental protection, high purity, and controllable structure. Nanocellulose synthesized by specific bacterial species under suitable conditions is called Bacterial Cellulose ( BC ) . It is a natural polymer material derived from microbial fermentation. It has high crystallinity, excellent biocompatibility and a unique three-dimensional nanonetwork structure.

1. Principles of fermentation preparation

The fermentation method mainly uses ** aceticobacter (such as Komagataeibacter xylinus ) to synthesize cellulose nanochains by metabolism in culture medium rich in carbon and nitrogen sources. Under static culture conditions, bacteria form a gel-like film on the liquid surface, gradually accumulating film-forming bacterial cellulose.

The formation process includes:

Carbon sources such as glucose are absorbed by bacteria;

Synthesis of intracellularly ;UDP- glucose

β-1,4- glucan chain catalyzed by cellulose synthase ;

Multiple chains are arranged into nanofiber bundles by self-assembly.

2. Typical preparation process

The strains are prepared
to use high-yield BC strains (such as Komagataeibacter xylinus ) to be activated and amplified in liquid seed culture medium.

The medium
is commonly used Hestrin-Schramm ( HS ) medium, and the main ingredients include: glucose, peptone, yeast powder, citric acid, potassium dihydrogen phosphate, etc.

Fermentation culture

Static culture : Let stand at 28–30°C for 7–10 days to form gel film BC；

Dynamic culture : can increase yield, but the products are mostly granular or short fibers and have a loose structure.

Cellulose Extraction and Purification
After the BC membrane was removed, NaOH or KOH was treated at 80~90°C for several hours, the bacteria and impurities were removed and washed until neutral.

Finished product treatment

BC hydrogel can be made ;

Freeze-drying to make films or powders;

Ultrasonic treatment forms a BC dispersion.

3. Advantages and technical characteristics of fermentation method

Features	illustrate
High purity	No impurities such as lignin, hemicellulose, and natural and pure
Nanostructure controllable	Three-dimensional network structure rules, fiber diameter is between 20 and 100 nm
Good biocompatibility	Suitable for medical dressings, artificial skin and other biomedical materials
Environmentally friendly and green	Raw materials can be agricultural waste, such as juice residue, sugar cane bagasse, etc.
Can be cultivated on a large scale	Suitable for a variety of bioreactor designs and industrial fermentation amplification

4. Wide application fields

Biomedical materials
are used to prepare artificial skin, trauma dressings, cell culture scaffolds, drug carriers, etc.

The food field
is used in low-calorie food additives, imitation meat product structure enhancers, etc.

Functional materials and composite materials
are used for flexible electrons, intelligent sensors, etc. after being compounded with conductive polymers and nanoparticles.

Prepare natural skin masks, moisturizers, oil control carriers, etc.
in the cosmetics field .

5. Future development trends

With the development of green manufacturing and biotechnology, the preparation of nanocellulose by fermentation is developing towards high yield, low cost and intelligent control . In the future, the technical path based on genetic engineering transformation of strains, fermentation process optimization and industrial equipment integration will promote BC to achieve greater breakthroughs in many fields such as medical care, food, and new materials.