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Cellulose

Cellulose is the Earth's major biopolymer and is of tremendous economic importance globally. Cellulose is the major constituent of cotton (over 94%) and wood (over 50%). Together, cotton and wood are the major resources for all cellulose products such as paper, textiles, construction materials, cardboard, as well as cellulose derivatives such as cellophane, rayon, and cellulose acetate.

Traditionally, cellulose is obtained from plant resources. Bolls from cotton plants are collected, and the fibers are detached from the seeds then processed into bales. In Texas alone, the 1992 cotton crop generated $1.0 billion in revenue and had an economic impact of $4.0 billion according to the Crop Biotechnology Center Datasheet on Cotton, Texas A & M University. The 1985 global production of cotton was approximately 17,540,000 tons.

Wood timber is cut from the forest and sent to the sawmill for cutting and drying. Transported to the paper mill where the wood is shredded into chips  and processed into a thick, watery pulp. This process requires energy and chemicals that are often harmful to the environment since unwanted lignin must be removed and the cellulose must be bleached. 

Pulp is made into paper and cardboard. In the United States alone, more than two million tons of newsprint and writing paper are produced each year from pulp (Moore, et al, 1995). The forest products industry in the United states is a $70. billion/year industry, not insignificant in relation to other major industries (from the Crop Biotechnology Center Datasheet on the Pine Biotechnology Program, Texas A & M University). In 1985, the world production of pulp reached 140 million metric tons (see Pulp and Paper, August, 1986, p 43)

With increasing population and the quest to continue using cellulose crops from wood and cotton, more land is required to meet the global demand. This has a direct impact on the earth's carbon cycle. In this context, we need to understand cellulose in terms of the global carbon cycle as well as its use by humans. The carbon cycle on earth is a vast interplay between the carbon dioxide of the atmosphere and its sequestration or "fixation" via photosynthesis into organic products, among which cellulose is the most abundant macromolecule on earth. Over 10 11 tons are estimated to be synthesized and destroyed annually on earth (Brown, 1979). 

Cellulose can be thought of as a giant carbon "sink" because carbon incorporation into cellulose remains in the product for a rather lengthy time, sometimes for thousands of years. The global warming cycle affected by the emergence of the industrial age is based, in part, by the release of carbon dioxide into the atmosphere through the burning of wood and hydrocarbons. This emerging problem could have immense consequences if the carbon dioxide content continues to rise and trap heat from the sun's irradiation. 

Thus, one long term alternative is to reverse this conversion by increasing photosynthesis which results in the trapping of more carbon dioxide. Harvesting huge acreage of trees is neither contributing to the ecological management of the photosynthetic potential, nor maintaining a global sink for carbon dioxide.

SOURCES OF CELLULOSE

Cellulose from such major land plants as forest trees and cotton is assembled from glucose which is produced in the living plant cell from photosynthesis. These are macroscopic, multicellular photosynthetic plants with which we are all familiar. In the oceans, however, most cellulose is produced by unicellular plankton or algae using the same type of carbon dioxide fixation found in photosynthesis of land plants. In fact, it is believed that these organisms, the first in the vast food chain, represent Nature's largest resource for cellulose production. Without photosynthetic microbes, all animal life in the oceans would cease to exist.

Several animals, fungi, and bacteria can assemble cellulose (Brown, 1979); however, these organisms are devoid of photosynthetic capacity and usually require glucose or some organic substrate synthesized by a photosynthetic organism to assemble their cellulose. Some bacteria can utilize methane or sulfur substrates to produce glucose and other organic substrates for cellulose. 

Gluconacetobacter Xylinus formerly known as ACETOBACTER XYLINUM-

A RICH SOURCE OF "Eco-friendly" PURE CELLULOSE 

Among the many bacterias, one of the most advanced types of purple bacteria is the common vinegar bacterium, Acetobacter. This non-photosynthetic organism can procure glucose, sugar, glycerol, or other organic substrates and convert them into pure cellulose (Brown, et al, 1976). 

Acetobacter xylinum is Nature's most prolific cellulose-producing bacterium. A typical single cell can convert up to 108 glucose molecules per hour into cellulose. Consider that as many as a million cells can be packed into a large liquid droplet, and if each one of these "factories" can convert up to 108 glucose molecules per hour into cellulose, the product should virtually be made before one's eyes. 

A single cell of Acetobacter has a linear row of pores from which glucan chain polymer aggregates are spun ( Figure 1). Image from R. Malcolm. Brown Lab

Acetobacter xylinum is a gram negative bacterium and is unique in its prolific synthesis of cellulose. Rows of pores characteristically secrete mini-crystals of glucan chains which then coalesce into microfibrils. Clusters of microfibrils result in a compound structure known as the ribbon. The ribbon can be observed directly using light microscopy, and the time lapse studies show Acetobacter cells generating cellulose. 

Acetobacter is the model system for study of the enzymes and genes involved in cellulose biosynthesis. The organism also promises to be an important future source for cellulose in the textile, paper, and lumber industries, provided its fermentation can be effectively scaled up. (R. Malcolm Brown Position Paper)

As many as one hundred of these pores can produce a composite cable of glucan polymers resulting in a ribbon. Time lapse analysis of individual Acetobacter cells assembling cellulose ribbons reveals a myriad of activities, each cell acting as a nano-spinneret, producing a bundle of sub-microscopic fibrils. 

Together, the entangled mesh of these fibrils produces a gelatinous membrane known as a pellicle. This membrane of pure cellulose, and cells entrapped within it can be cleaned and dried and the product used for many exciting new applications. One of the unique features of this pure cellulose membrane is that it is very strong in the never dried state, and it can hold hundreds of times its weight in water. This great absorbtivity and strength constitute two of the many novel features of microbial cellulose (Brown, 1989; Brown, 1992; Brown, 1994; White and Brown, 1989).

UNIQUE MICROBIAL CELLULOSE FEATURES AND "Eco-friendly" PRODUCTS

Because the microbial cellulose ribbons are "spun" into the culture medium, membranes and shaped objects can be produced directly during the fermentation process, thus enabling a novel array of non-woven products. Direct dyes can be added during synthesis to alter the cellulose produced. 

Because of the novel features of microbial cellulose, a variety of product applications of microbial cellulose is possible.  

Before we explore deeper into the applications of Microbial Cellulose, allow me to trace back the first use of this prolific producer of Microbial Cellulose.

 Nata De Coco

Nata De Coco is a chewy, translucent, gel like edible substance produced through fermentation of the vinegar bacteria called Gluconacetobacter Xylinus formerly identified as Acetobacter Xylinum (a gram negative bacterium) that was commonly found in grape to wine fermentation process.

Undocumented claim surface that Nata De Coco was first discovered in Pina cloth producing factory in Laguna.  Workers noticed a thin layer of gelatinous film floating in the tank of pineapple juice waste; a raw material used as a bleaching agent for Pina cloth.


The rotting waste of pineapple juice yielded a thin layer of slimy gel floating and growing in thickness each day. This triggered an inquiry. Further study from sugared pineapple pulp mash was then conducted by certain Villanueva.

Earliest investigators to report on this product believed that it is chiefly Dextran (discovered by Louis Pasteur --- a microbial product of wine), and hinted that the likely causal agent is a bacterium belonging to genus Leuconostoc. 

The nata-forming organism was first referred to as Leuconostoc mesenteroides (Cienkowski) van T’eghem by Adriano et al. who described the product that  forms in the pineapple juice waste as a mucilaginous substance which consists of Dextran. This was believe to be the birth of Nata de Pina. No exact date was known but Philippines has been producing and exporting Nata De Coco after World War II (sometime in the late 40’s).

Apparently, following similar trend, Africa, who studied the production of Nata from coconut water included in her report a review of the history of Dextran-forming L. mesenteroides for the Nata organism, which is considered to be identical with the one under study. 

Another researcher, a certain Mendoza identified the Nata forming organism as Acetobacter aceti (Kutzing) Beijerinck and described it as a capsulated bacterium which “produces a gelatinous substance on the surface of a suitable substrate of proper acidity and sugar solution.” 

A total of four papers appeared in PJS dealing with Nata De Coco, a whitish cellulosic gel which is obtained by microbial fermentation of coconut water.

  • Brooke, Walter L., “The deodorization of coconut oil,” PJS, 30(2), 201-212, June 1926.
  • Lava, V.G., P.E. Torres, and S. Sanvictores, “Chemical studies on coconut products, III:
  • A new process for the extraction of coconut oil,” 74(3), 241-284, March 1941;
  • Lava, V.G., P.E. Torres, and S. Sanvictores, “Chemical studies on coconut products, IV: Further data on a new process for the extraction of coconut oil,” PJS, 75(2), 143-158, June 1941.237Volume 1(Coconut)the optimal conditions for producing nata.
Almost 20 years later, Gossele and Wings, two Belgian researchers published another paper in PJS which identified the nata-producing bacterium as Acetobacter hansenii. 

The information here was gathered from a 1967 published journal authored by Martina Lapuz, Emma Gallardo and Macario Palto --- Phil. Journal of Science Vol. 96 No. 2 June 1967 (Pages 92-93) where they presented a study investigating the process of enhancing the production after the causative microbe was identified.

Their study led to the discovery of a different substrate yielding thicker and more structured gel. The newly discovered process and formula of medium where the organism thrives, study the behavior of the microorganism's growth in terms of temperature, level of acidity and additional solutions necessary for optimal yield of Nata gel. 

As a result, a window of opportunity opened to the Filipino public to monetize on the emerging technology in the coconut industry. Using the coconut water, coconut milk, sugar, right amount of acidity and the mother starter from the microbe Gluconacetobacter Xylinus --- giving birth to the discovery of Nata De Coco.

Nata De Coco was embraced by the public as an affordable desert. Gaining mass popularity because of it's taste the notoriety spread nationwide quickly.

In the early 90’s, Nata De Coco had a surprising boom in the export market when it created a surge of demand from Japan.  Armed with simplified method of production, the Phil. Gov't. through it's livelihood program administered via DOST (Department of Science and Technology) implemented the transfer of technological information and production training workshop among livelihood projects and small scale private enterprise to keep up with the demand. 

The recorded revenue in 1991 for export in Japan was around $ 170, 000.00.

The following year, a fad originated in Japan with the introduction of Nata De Coco into diet drinks enjoyed by young girls. The export revenue skyrocket.

Meanwhile, another $ 2.1 million in revenue was also generated from Taiwan market. in that same year.

Nata earned the distinction as among the 30 best hit products among Japanese consumers for 1993. 

Since this time, the export of Nata from the Philippines has risen from approximately $1 million per year to more than $26 million annually as of 1993 (see Philippine Daily Inquirer "Agriculture" Vol. 20. March 3, 1994).

The Nata De Coco industry claims it's place in the GDP.

In fact, the cottage industry in the Philippines cannot meet the demand for export, so great interest has recently focused on ways and means to increase Nata production.

As the demand continued, backyard production proliferated and waste disposal became a concern. 

In the late 90's the export demand simmered down as other countries like Thailand, Indonesia and Malaysia join bandwagon of production and export trade. 

Nata De Coco remained popular but with lesser demand from Japan and Taiwan. However, because of the increasing number of Filipinos working abroad, the market remains lucrative up to this writing.

   


 

This is how a raw Nata De Coco would look like in the tray before cutting into dice and bottled



Microbial Cellulose sits like a slab of gel --- before harvest  


 Stack of Nata De Coco (Microbial Cellulose)  Gel Slabs


Large size gel grown from elongated tray from cultured Kombucha or Manchurian Tea...note the tea colored sheet

 This shows to prove that the organism is adaptable to size and color of the medium use in the production.


The image below is a dried sheet sold under the brand name Dermafill. A translucent, semi-opaque biosynthetic cellulose membrane dressing, which at a microscopic level closely resembles the body's own collagen. The nonwoven ribbons of microbial cellulose closely resemble the body’s extracellular matrix yielding a high vapor transfer rate while providing a normal matrix covering the entire wound bed. The result is a fluid balance and mechanical cellular matrix which bridges the wound bed, thus promotes distribution and concentration of growth factors and nutrients needed for healing, while protecting the wound from environmental contamination. Reference: Here

 Notice how thin the sheet in it's dehydrated state...

Bacterial cellulose (BC) dry film was developed and inoculated with antibacterial properties. 

Marketed as a functional wound dressing for acute trauma treatment and chronic ulcers. 

To achieve this, a freeze-dried BC film was immersed in a benzalkonium chloride solution, which belongs to cationic surfactant type antimicrobial agent, followed by another freeze-drying step. Some physical and antimicrobial properties of the prepared BC films were investigated and the results showed that the drug-loading capacity of the BC dry film was about 0.116 mg/cm2 when soaked in 0.102% benzalkonium chloride solution. 

High water absorbing capacity, an important quality for wound dressings was also achieved with a swelling ratio of 26.2 in deionized water and of 37.3 in saline solution. With respect to the antimicrobial effect, a stable and prolonged antimicrobial activity for at least 24 h was obtained especially against Staphylococcus aureus and Bacillus subtilis, which were generally Gram-positive bacteria that are commonly found on contaminated wounds.

Remarkable products from Microbial Cellulose introduce into the global market

The Nata De Coco desert, the Diet Drink and Wound Dressing. All prove to be beneficial to the public consumption.

Nata De Coco, Diet drink and Healthy Kombucha Tea provide solutions to the growing problems of Obesity.

Why? 

  • Because it is rich in dietary fiber, matter of fact, the Nata De Coco when absorb is not-digestible. Meaning the fiber can act as a cleanser to the digestive tract. 
  • Low Calorie --- only 80 kilo-calorie per 100 grams serving
  • 1 kilo-calorie per gram if taken plain
Wound dressing - the ease of use is obvious not to mention the numerous successful studies made from reputable companies earning the approval of FDA in the USA and FDA equivalent in UK.

Audio Components

Sony Corporation, in conjunction with Ajinomoto developed the first audio speaker diaphragms using microbial cellulose (see US Patent 4,742,164). The first headphones were very expensive, over $3,000 for one pair! The price recently has dropped, and the microbial cellulose headphones are available worldwide as an upper end audio product. The unique dimensional stability of microbial cellulose gives rise to a sound transducing membrane which maintains high sonic velocity over a wide frequency ranges, thus being the best material to meet the rigid requirements for optimal sound transduction. On the horizon, it is expected that larger speaker diaphragms will be made of microbial cellulose.

Paper and Paper Products

Microbial cellulose has been investigated as a binder in papers, and because of it consists of extremely small clusters of cellulose microfibrils, this property greatly adds to strength and durability of pulp when integrated into paper. Ajinomoto Co. along with Mitsubishi Paper Mills in Japan are currently active in developing microbial cellulose for paper products (see patent JP 63295793).

Advantages over traditional plant cellulose is it's purity meaning the absence of lignin and hemicellulose that requires a lot or energy and chemicals, a extensive process to get rid off.

No bleaching required, and high tensile strength because of the structure. Would be a great material for specialty and archival papers or even as additive to recycled paper.

Hydrogel - Soft Tissue Replacement

A patent is currently being submitted for composite materials formed from a hydrogel and cellulose, and more particularly the present invention relates to new types of poly(vinyl alcohol)-bacterially produced cellulose composites suitable for soft tissue replacement and controlled release.

Artificial Blood Vessel -- almost similar to soft tissue replacement.

Helen Fink, a molecular biologist from the University of Gothenburg, Sweden, has been investigating the use of bacterial cellulose to create artifical blood vessels. She used Gluconacetobacter xylinus, (previously known as Acetobacter xylinum), the same cellulose-producing bacteria I use in BioCouture.

The cellulose is strong enough to cope with blood pressure and works well with the body's own tissue. Fink's thesis shows that the material also carries a lower risk of blood clots than the synthetic materials currently in use.

"There are hardly any blood clots at all with the bacterial cellulose, and the blood coagulates much more slowly than with the materials I used as a comparison," says  Fink. "This means that the cellulose works very well in contact with the blood and is a very interesting alternative for artificial blood vessels."

Real blood vessels have an internal coating of cells that ensure that the blood does not clot. Helen Fink and her colleagues have modified the bacterial cellulose so that these cells adhere better.

"We've used a brand new method which allows us to increase the number of cells that grow in the bacterial cellulose without changing the material's structure," says Fink. Reference: Here

Contact Lens 

The present invention relates to microbial cellulose materials having a convex surface that molds to the shape of the eye covering the cornea and limbus and can be corrective or non-corrective of vision.

DETAILED DESCRIPTION OF THE INVENTION

The contact lens of the present invention is formed from a material containing microbial cellulose (MC). In a preferred form of the invention, the MC may be obtained by biosynthesis through the bacteria of the genus Gluconacetobacter. Until recently, this microorganism was known as Acetobacter xylinum. However, the phylogeny of acetic acid bacteria, of which Acetobacter xylinum is a member, was corrected in 1998 based upon the sequences of 16S ribosomal RNA, and the subgenus Gluconobacter was elevated to the generic level. In addition, the original spelling, Gluconoacetobacter [sic], has been corrected in accordance with Rule 61 on the occasion of validation to Gluconacetobacter. Acetobacter xylinus has been transferred to the genus Gluconacetobacter and is now recognized as Gluconacetobacter xylinus ( G. xylinus ).

Microbial cellulose derived from G. xylinus is a preferred material for forming contact lenses.

G. xylinus cellulose film is available for purchase under the name DERMAFILL from Microbial Cellulose Technology of Northbrook, Ill. The DERMAFILL film is sterile packaged in dry form and is opaque. On wetting with tears or physiological saline solution it becomes transparent. DERMAFILM is believed to be made in accordance with the disclosure in U.S. Pat. No. 4,912,049, which is incorporated herein by reference and made a part hereof.The G. xylinus cellulose is biodegradable, non-toxic, non-pyrogenic, hypoallergenic, and may be sterilized.

The material is sufficiently flexible when formed into a contact lens to conform to the shape of an eye. The material also strongly absorbs light within the UV spectral range between 250 to 400 nanometers, and is non-absorbing, and, therefore, transparent in the visible and infrared light ranges above about 400 nanometers. Accordingly, the contact lenses of the present invention are capable of scattering incident laser light and can protect a wearer from laser blinding or ocular tissue damage.

Microbial Cellulose: Poised For A High-Profile Role In Biomedicine

Science Daily (Feb. 21, 2007) — Biotechnology's next high-value product could be microbial cellulose, a form of cellulose produced naturally by bacteria that already has found some successful applications in medicine, according to an article in the current issue of the American Chemical Society's Bio-macromolecules, a monthly journal.

In their review of worldwide research on microbial cellulose, the University of Texas' R. Malcolm Brown Jr. and colleagues in Poland explain that it is chemically identical to the more-familiar plant cellulose, source of paper and other commercial products.

However, cellulose produced by the bacterium Acetobacter xylinum has a unique nanostructure of fibers that make it ideal as a dressing to speed wound healing and for a range of other biomedical applications.

Microbial cellulose already has been used successfully in patients with severe burns, for instance, and as a replacement for small-diameter blood vessels, the scientists point out.

Based on the review, they conclude that microbial cellulose is poised for use in a wide variety of medical devices and consumer products as soon as scientists develop a method to mass produce the material.

Other potential Industrial Application mentioned in the study of R. Malcolm Brown one of the leading researchers for the Industrial Applications of Microbial Cellulose from University of Texas are the following:

Food Industry

  • Thickeners (ice cream and salad dressing)
  • Weight reduction base
  • Base for artificial meat
  • Sausage and meat casings

Health Industry

  • Serum cholesterol reduction (see US Patent 4,960,763)
  • Drug delivery agents, either oral or dermal
  • Artificial skin substrate
  • Soft Tissue Replacement
  • Blood Vessel replacement

Cosmetics and Beauty

  • Skin creams
  • Astringents
  • Base for artificial nails
  • Thickener and strengthener for fingernail polish

Environmental

  • Oil spill cleanup sponge
  • Absorptive base for toxic material removal
  • Insulation 

Petroleum and Mining

  • Mineral and oil recovery ( see US Patents 5,011,596 and 5,009,797)
Clothing and Shoe

  • Artificial leather products
  • One piece textiles
Outdoor Sports

  • Disposable tents and camping gear

Public Utilities

  • Water purification via ultra filters and reverse osmosis membranes (see patent by Nakano Sumise JP 3032726)

Babycare Products

  • Disposable recyclable diapers
Forest Products

  • Artificial wood strengthener (plywood laminates)
  • Filler for paper
  • High strength containers

Specialty Papers

  • Archival document repair
  • Paper base for long-lived currency

Automotive and Aircraft

  • Car bodies
  • Airplane structural elements
  • Rocket casings for deep space missions