Bacterial cellulose preparation: the optimization path from static culture to dynamic fermentation

As a novel biological material, bacterial cellulose has its unique nanofiber network structure that imparts excellent mechanical properties, biocompatibility and degradability. It has shown huge application potential in biomedical, food, cosmetics and other fields. The traditional static cultivation method has problems such as low production efficiency and high cost, which is difficult to meet the needs of industrial production. In recent years, the introduction of dynamic fermentation technology has brought new opportunities for the large-scale preparation of bacterial cellulose. This article will discuss the key influencing factors and optimization strategies in the preparation of bacterial cellulose from the perspective of dynamic fermentation.

1. Dynamic fermentation: breaking through the limitations of static culture

The traditional static culture method uses shallow dish culture, and bacteria form cellulose membranes on the surface of the liquid culture medium. This method is simple to operate, but has many limitations: low production efficiency, uneven product thickness, poor quality transfer efficiency, etc. Dynamic fermentation technology significantly improves the mass transfer conditions and improves the yield and quality of bacterial cellulose by introducing stirring, ventilation and other operations.

During the dynamic fermentation process, the design and operating parameters of the fermenter have an important influence on the yield and properties of bacterial cellulose. The type of fermenter, stirring speed, ventilation volume, pH value, temperature and other factors need to be optimized. For example, higher stirring speeds can improve mass transfer efficiency, but excessive shear forces may affect bacterial growth and cellulose synthesis.

2. Key influencing factors in dynamic fermentation process

Bacteria species are a key factor affecting the yield and quality of bacterial cellulose. Acetobacterium leukococcus is the most widely studied bacterial cellulose production strain, which has a high cellulose synthesis ability. In recent years, researchers have transformed bacterial strains through genetic engineering and other means to further improve their cellulose yield and performance.

The composition of the culture medium is crucial for the synthesis of bacterial cellulose. The concentration and proportion of nutrients such as carbon sources, nitrogen sources, and inorganic salts need to be optimized. For example, glucose is a commonly used carbon source, but its concentration is too high to inhibit bacterial growth. In addition, adding certain additives, such as ethanol, lactic acid, etc., can promote the synthesis of bacterial cellulose.

Fermentation conditions, such as temperature, pH, dissolved oxygen, etc., have an important impact on bacterial growth and cellulose synthesis. For example, the optimal growth temperature of Acetobacterium leucorrhea is generally 28-30°C and the pH is 4.0-6.0. The dissolved oxygen amount is a key parameter in the dynamic fermentation process and needs to be optimized according to the characteristics of the bacterial species.

3. Optimization strategy for dynamic fermentation technology

To improve the yield and quality of bacterial cellulose , researchers have developed a variety of dynamic fermentation techniques. For example, new fermentation tanks such as air-lift fermentation tanks and rotary wall bioreactors can improve mass transfer efficiency and promote the synthesis of bacterial cellulose. In addition, operating methods such as fed feed batch fermentation and continuous fermentation can also improve production efficiency.

Process control technologies, such as online monitoring, feedback control, etc., can achieve precise control of the fermentation process and improve the production efficiency and product quality of bacterial cellulose. For example, by monitoring parameters such as dissolved oxygen, pH, etc. online, the fermentation conditions can be adjusted in time to ensure that the bacteria are in the optimal growth state.

In the future, with the continuous development of technologies such as synthetic biology and metabolic engineering, the dynamic fermentation technology of bacterial cellulose will develop in the direction of efficiency, controllability and intelligence. By building efficient bacterial seeds, optimizing fermentation processes, and developing new reactors, the yield and quality of bacterial cellulose will be further improved, production costs will be reduced, and its application in various fields will be promoted.

In short, dynamic fermentation technology provides new ideas and methods for the large-scale preparation of bacterial cellulose. By optimizing bacterial strains, culture media, fermentation conditions and fermentation processes, the yield and quality of can be significantly improved bacterial cellulose , laying the foundation for its application in various fields.