请输入您要查询的百科知识：

　

词条 Microbial cellulose
释义

  1. Production

      Differences with plant cellulose    Disadvantages for commercial use  

  2. Functions

  3. Uses

     Medical  Non medical 

  4. References

  5. External links

{{merge|Bacterial cellulose|discuss=Talk:Microbial cellulose#Proposed merge with Bacterial cellulose|date=July 2018}}Microbial cellulose, sometimes called bacterial cellulose, is a form of cellulose that is produced by bacteria. It is widely used in the Filipino dessert Nata de coco. The earliest articles describing microbial cellulose was from 1931,[1] it was subsequently identified as cellulose in 1934.[2]

Production

Bacteria from the genera Aerobacter, Acetobacter, Achromobacter, Agrobacterium, Alacaligenes, Azotobacter, Pseudomonas, Rhizobium, and Sarcina synthesize cellulose.[3] However, only the Gluconacetobacter produce enough cellulose to justify commercial interest. The most extensively studied species is Gluconacetobacter xylinus, formerly known as Acetobacter xylinum and since reclassified as Komagataeibacter xylinus.[3]

G. xylinus extrudes glycan 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.

Differences with plant cellulose

Some advantages of microbial cellulose over plant cellulose include:

  • Finer and more intricate structure
  • No hemicellulose or lignin to be removed
  • Longer fiber length: much stronger and wider
  • Can be grown to virtually any shape and thickness
  • Can be produced on a variety of substrates
  • The formula of the media used and the strain of Acetobacter xylinum will determine the quality of the pellicle
  • More absorbent per unit volume

Disadvantages for commercial use

Some issues that have prevented large-scale commercialization so far include:

  • High price (about 50 x more than plant cellulose)
    • Because of high-price substrates: sugars
    • Low volumetric yields
  • Lack of large-scale production capacity
  • Timely expansion and maintenance of the cell culture for production

Functions

One continuing mystery surrounding microbial cellulose is its exact biological function. A. xylinus, since been renamed as Gluconacetobacter xylinus and more recently as Komagataeibacter xylinus, is a successful and prevalent bacterium in nature, frequently finding a home in rotting fruits and sweetened liquids. The most familiar form of microbial cellulose is that of a pellicle on the top of a static cultured growth media. It has, thus, been hypothesized that cellulose acts as a flotation device, bringing the bacteria to the oxygen-rich air-media interface. This hypothesis has largely been discredited by experiments conducted on submerged oxygen-permeable silicone tubes that show that cellulose grows well submerged if enough oxygen is present.[4] Others suspect that cellulose is used to immobilize the bacteria in an attempt to keep it near the food source, or as a form of protection against ultraviolet light.[5]

Uses

Medical

Microbial cellulose is biocompatible and non-toxic, making it a good candidate material for medical applications.[6] So far it has found a commercial role in some wound dressings. There is on-going research to evaluate a possible role for bacterial cellulose in the following applications:

  • Scaffolds for tissue engineering
  • Synthetic dura mater[7]
  • Bladder neck suspension
  • Soft tissue replacement
  • Artificial blood vessels

Non medical

  • Matrix for electronic paper{{citation needed|date=March 2018}}
  • High-strength paper
  • Diet foods
  • Desserts: nata de coco
  • Substrates for OLEDs
  • Sony has used microbial cellulose as an acoustic membrane in high-end earphones[8]
  • It was patented in 1988 for possible use as a glossy surface finish in magazines[9]

References

1. ^Tarr, H. L. A., and Harold Hibbert. "Studies on reactions relating to carbohydrates and polysaccharides. XXXV. Polysaccharide synthesis by the action of Acetobacter xylinus on carbohydrates and related compounds." Canadian Journal of Research 4.4 (1931): 372-388.
2. ^Barsha, Jacob, and Harold Hibbert. "STUDIES ON REACTIONS RELATING TO CARBOHYDRATES AND POLYSACCHARIDES: XLVI. STRUCTURE OF THE CELLULOSE SYNTHESIZED BY THE ACTION OF ACETOBACTER XYLINUS ON FRUCTOSE AND GLYCEROL." Canadian Journal of Research 10.2 (1934): 170-179.
3. ^1 P. Ross, R. Mayer, and M. Benziman (1991) "Cellulose biosynthesis and function in bacteria," Microbiol Mol Biol Rev, vol. 55, no. 1, pp. 35-58, Mar.
4. ^T. Yoshino, T. Asakura, and K. Toda, "Cellulose production by Acetobacter pasteurianus on silicone membrane," Journal of Fermentation and Bioengineering, vol. 81, no. 1, pp. 32-36, 1996.
5. ^S. Williams and R. Cannon, "Alternative Environmental Roles for Cellulose Produced by Acetobacter xylinum," Applied and Environmental Microbiology, vol. 55, pp. 2448-2452, Oct. 1989.
6. ^G. Helenius, et al., "In vivo biocompatibility of bacterial cellulose," Journal of Biomedical Material Research: Part A, vol. 76A, no. 2, pp. 431-438, 2005.
7. ^{{cite web|url=http://clinicaltrials.gov/ct2/show/NCT00454844 |title=SyntheCel Dura Replacement in Patients Requiring Dura Repair|publisher=ClinicalTrials.gov |date= |accessdate=2010-03-31}}
8. ^Y. Nishi, et al., (1990) "The structure and mechanical properties of sheets prepard from bacterial cellulose," Journal of Materials Science, vol. 25, no. 6, pp. 2997-3001.
9. ^D. C. Johnson, A. N. Neogi, and H. A. Leblanc, (Mar. 10, 1988) "Bacterial cellulose as surface treatment for fibrous web," {{US Patent|4861427}}

External links

{{Commons category|Bacterial Cellulose|Microbial cellulose}}

2 : Cellulose|Nanomaterials
随便看

　

开放百科全书收录14589846条英语、德语、日语等多语种百科知识，基本涵盖了大多数领域的百科知识，是一部内容自由、开放的电子版国际百科全书。

　

Copyright © 2023 OENC.NET All Rights Reserved
京ICP备2021023879号 更新时间：2024/11/13 18:56:53