Microbial cellulose

Microbial cellulose is a form of cellulose that is produced by bacteria.



Production
Bacteria from the species of Aerobacter, Acetobacter, Achromobacter, Agrobacterium, Alacaligenes, Azotobacter, Pseudomonas, Rhizobium and Sarcina synthesize cellulose. However, only the Acetobacter species produce enough cellulose to justify commercial interest. The most extensively studied member of the Acetobacter species is A. xylinus, formerly known as A. xylinum.

A.xylinus extrudes glucan chains from pores into the growth medium. These aggregate into microfibrils, which bundle to form microbial cellulose ribbons.Various kinds of sugars are used as substrate. Production occurs mostly at the interface of liquid and air. This is due to the high oxygen demand of the Acetobacter.

Advantages Over Plant Cellulose
Some advantages of microbial cellulose over plant cellulose include:
 * Finer structure
 * No hemicellulose or lignin need to be removed
 * Longer fiber length: much stronger
 * Can be grown to virtually any shape

Disadvantages for Commercial Use
Some issues that prevented larger scale commerciaization so far include:
 * High price (about 100 x more than plant cellulose)
 * Because of high priced substrates: sugars
 * Low volumetric yields
 * Lack of large scale production capacity

Potential Future Improvements

 * Use of cheaper substrates (e.g. lactose)
 * Better production methods
 * Bio reactors: rotating biological contactors, membrane reactors

Potential and Current Products

 * Wound dressing
 * Matrix for electronic paper
 * Scaffolds for tissue engineering
 * High strength paper
 * Artificial blood vessels
 * Diet foods
 * Desserts: nata de coco