WO1989011783A2 - Microbial cellulose composites and processes for producing same - Google Patents

Abstract

A process for treating a variety of objects utilizing microbial cellulose produced in situ or applied as a film. Also disclosed is a process for manufacturing currency from microbial cellulose.

Description

MICROBIAL CELLULOSE COMPOSITES AND PROCESSES FOR PRODUCING SAME

Background of the Invention

The present invention relates to microbial cellulose composites and structures formed therefrom. Additionally, the invention relates to processes for preparing the microbial cellulose structures. More specifically, microbial cellulose (MC) made by certain microorganisms, especially the Acetobacter xylinum bacterium (AB), can be used to produce in situ composites and structures by a variety of predetermined means, such as by filling and covering interstices in porous materials, such as paper, fabrics, filters, membranes, and condoms. The microbial cellulose alters porosity and permeability and supports and protects both porous and nonporous materials. In addition, the microbial cellulose can be used to fabricate entirely novel MC-containing compositions and multicellular articles.

Miicrobial cellulose (MC) is the product of a unique class of microorganisms (M) capable of forming microscopic cellulose ribbons as part of their life cycle. Acetobacter xylinum (AB) is a species of this class, well described in the patent literature, such as in U.S. Patent No. 4,378,431 and U.S. Patent No. 4,588,400. The prior art has generally recognized that microbially-produced, cellulose microfibrils are essentially usable directly for end-use and product applications in which the unusual physical properties characteristic of microbially-produced, cellulose microfibrils are useful. Examples of such uses include U.S. Patent 4,588,400 in which microbially-produced, cellulose microfibrils pads are used to retain medical fluids, in a manner similar to a cotton pad or a fabric holding liquids. U.S. Patent No. 4,378,431 utilizes the cellulosic character of microbially-produced, cellulose microfibrils to coat other fibers and fabrics to impart a cellulosic characteristic to the surface thereof. Thereby, articles having such coated fibers have the feel, dyeability, printability, liquid sorbtion and other characteristics of cotton fabrics.

U. S. Patent No. 4,742,164 teaches a particular process for producing molded articles using microbial cellulose. The articles are noted for their high dynamic strength and modulus of elasticity.

Even though the above references are fairly recent, the technology continues to develop in this area, and improvements in the methodology for growing the microbial cellulose has resulted in the capacity to produce a variety of end products.

Summary of the Invention

Therefore, an object of the present invention is to provide improved processes for growing microbial cellulose and using same to produce certain improved structures. Detailed Description of Preferred Embodiments

Processes for producing microbial-produced, cellulose microfibrils as the starting material for many of the inventive features herein are well-known to the art. In general, examples of such techniques are described in U. S. Patents No. 4,378,431; No. 4,588,400; and No. 4,742,164, the disclosures of which are hereby incorporated by reference.

Any microbial strain capable of generating cellulose is generally usable for the processes, articles, composites and compositions of the present invention. These will be generically referred to as cellulose producing microbes (M). More specifically, those in the Acetobacter, Rhizobium, Agrobacterium, Alcaligenes, and Pseudomonas genera, as described by the present inventor in his article in J. Applied Science: Appl. Polymer Symp. (1983) 37, 33-78 are preferred. The species Acetobacter xylinum (ACX) is particularly preferred and, unless expressly indicated otherwise, was used as the basis for the inventive concepts described herein. More particularly, those strains of microorganisms within the listed genera, which reverse direction during cellulose production are preferred.

The microbes are placed in a culture medium. The major constituent of the culture medium for ACX preferably is a soluble polysaccharide, particularly sugar (sucrose), more particularly a hexose, and especially glucose.

Suitable nutrients are well known to the art. One known as Schramm & Hestrin medium is especially preferred. It generally comprises about 20 g/1 glucose, 5 g/1 peptone, 5 g/l yeast extract, 2.7 g/l anhydrous dibasic sodium phosphate, and 1.15 g/l citric acid monohydrate. Corn steep liquor and molasses are practical and inexpensive sources of the hexose component preferred in the nutrients of the invention. Another satisfactory nutrient composition comprises about 8 volume percent vinegar, 5 volume percent ethanol and 4 weight percent malt extract. The pH is preferably adjusted to about 3 to 6, most preferably about 3.5 to 5.5. When it is desired to increase the amount of oxygen-containing components in the nutrient, additional alcohols and mixtures thereof can be included in the nutrient.

The ambient temperature for maximum effectiveness of microbial cellulose production is about 15 to 40, preferably about 20 to 30 degrees Centigrade. The total amount of time needed for acceptable cellulose production is generally from about 1 to 25 days. Techniques for improving microbe growth and increased cellulose production from each microbe are contemplated by this invention.

In copending U.S. Serial No. 684,844, filed on December 21, 1984, and entitled "Production of Microbial Cellulose", on which the instant inventor is a coinventor, a comprehensive inventive scheme is disclosed for utilizing cellulose-producing microbes for producing shaped cellulosic objects on or within a template. Various chemical and physical modifications are disclosed to enhance and improve such shaped objects. Similarly, this inventor's U.S. Patent No. 4,378,431 utilizes an existing fibrous/fabric structure as a template/substrate for depositing a thin layer of cellulose in situ from cellulose producing microbes. That approach essentially utilizes the shape-forming ability of cellulose producing microbes to form cellulose-containing shapes that also could have been formed from slurries of cotton/conventional cellulosic fibers, even though such a process is not as practical as that based on the cellulose-producing microbe techniques. The conventional product of cellulose-producing microbes is a mass of intertwined submicron ribbons comprised of cellulosic microfibrils. These ribbons are generated at the oxygen-containing gas (air is operable)/nutrient interface. The nutrient medium contains the cellulose-producing microbes. The mass of intertwined ribbons is translucent and insoluble, but very hydrophilic and wettable. It also has great tensile strength. It appears to be a gel to sight and touch. It has exceptionally high wet and dry tensile strength, as well as excellent dimensional stability.

The breakthrough inventive concepts of the present invention are improvements in the method of manufacturing the microbial cellulose. The resulting cellulose evidences unique properties which lead to utility for a number of new applications. As disclosed in copending application U. S. Serial No. 199,906, filed May 28, 1988, and entitled "Microbial Cellulose as a Building Block Resource for Specialty Products and Processes Therefor", certain properties are selected so that microbial cellulose is adapted and tailored to be utilized in processes, products and compositions having no counterpart in the prior art.

According to the present invention, the microorganisms for growing the microbial cellulose are specifically selected strains from the Acetobacter, Rhizobium, Agrobacterium, Alcaligenes, and Pseudomonas genera. The strains are those which have periodic reversal in cellulose synthesis. These strains include H1A, H1B, H1C, H2A, H2B, H5C, H5D, H6C, H14B, H15A, AND H15B ; particularly preferred is the NQ-5 strain (American Type Culture Collection No. 53582). These strains are described in more detail in United States Serial No. 023,336, filed March 9, 1987, and entitled "Multiribbon Microbial Cellulose", the disclosure of which hereby is incorporated by reference. This results in the cellulose-producing microorganism shuffling, at least periodically, first in one direction and then in the other direction along a length of an earlier deposited cellulose ribbon to add another cellulose ribbon thereto and produce a cellulose ribbon-bundle having a width of at least two cellulose ribbons.

In addition, according to the present process, it has been discovered that the size of the initial microorganism seed is important, in that the larger the seed the more dense is the product.

Also, it has been discovered that the use of agents which interfere with the crystallization process, but not the polymerization process, result in an improved product. A variety of agents are useful, particularly preferred is carboxymethylcellulose (CMC) . These agents are more specifically discussed in United States Serial No. 022,904, filed March 6, 1987, and entitled "Microbial Cellulose Modified During Synthesis", the disclosure of which hereby is incorporated by reference.

In addition to these process steps, the present invention recognizes that the cultivation of the cellulose-producing microorganism to produce cellulose I or a crystalline polymorph thereof, at the exclusion of cellulose II, produces a preferred product.

The cellulose microfibrils produced from microbes according to the present invention have submicron cross-sectional diameter dimensions of from about 1.5 nm (nanometers) [0..0015 micron] to 10 nm (0.01 micron). This results in an enormous fiber surface area per cubic volume of fiber. Moreover, the submicron dimensioned cellulose fibrils produced by microbes have exceptionally high wet and dry tensile strengths. These microfibrils are especially noteworthy with respect to their remarkably high length to diameter ratio which can be in the order of as much as millions to one. One preferred embodiment of the present invention is in situ application to paper documents, especially fragile acid-damaged paper documents or those likely to become so. Another is a modified currency product of improved longevity and anti-counterfeiting aspects. Encapsulation of artifacts and growing MC in situ on bubbles to form multicellular three-dimensional structures (MC3DS) are other features, but the invention is not so limited.

Referring again to the first-mentioned application, it is known that many documents made from paper, particularly old ones, are highly susceptible to degradation because of the high residual inorganic acidity produced by many conventional paper producing methods, particularly for inexpensive papers. Accordingly, archives and other repositories of valuable books, manuscripts and other documents are acutely concerned with the innate, inevitable degradation of their collections. A great deal of effort has been devoted over the years to find means to alleviate this problem.

These efforts of the art are extensively described, for example, in an article appearing in the American Scientist entitled, "Preservation of Libraries and Archives" by Shahani and Wilson, pp. 240-251, Vol. 75, May-June 1987, the disclosure of which is incorporated herein by reference.

Although the Library of Congress is proceeding with a pilot unit which will expose acidic paper materials to diethyl zinc (DEZ) vapors. Briefly, this process is characterized by treating the dampened acidic, deteriorated paper with a DEZ in a vacuum chamber. This is subsequently evacuated after in situ zinc oxide is deposited on the paper surface. The process has been plagued with the outbreak of fires. No entirely satisfactory technique of retarding degradation and restoring such materials is yet known to the art. Emphasis is on new books, since DEZ does not provide structural integrity. Also, after a book is very fragile, DEZ is not cost-effective. The DEZ process is covered by U.S. Patent No. 3,969,549.

The National Library of Vienna is researching a preservation process which involves a liquid comprising a polyvinyl chloride (PVC) emulsion and methyl cellulose. Another approach being explored by a British governmental agency involves deposition of parylene vapors.

The disadvantages of the art, as well as the achievement of many other useful and novel utilizations, can be remarkably overcome by the inventions described herein.

The restoration process of the instant invention can be applied to paper substrates to provide enhanced longevity and improved structural integrity. A leading example of the applicability of the present invention involves its advantageous use with the DEZ process described above. The technique of the instant invention can be employed on a given paper substrate after the DEZ treatment or as a substitute therefor. Regardless of whether acidity has been neutralized by a treatment such as by DEZ, the substrate paper requires a transparent, compatible support to maintain or restore its physical integrity. This is accomplished by the M, preferably AB, process technique of the invention. Once integrity has been enhanced by the technique of this invention and some protection from future degradation imparted thereto, further degradation of residual acid may be tolerable. Thus, the necessity for DEZ or comparable treatment will be obviated by the technique of this invention.

One embodiment of the instant described process involves forming MC in a relatively wet environment, e.g., a liquid nutrient bath. The invention also contemplates MC formation simply in a damp environment. Thus, individual pages or a multiplicity of pages, such as in a book, can be sprayed with a solution of M, i.e., AB, and closed. Sufficient MC will be created in situ in the interstices and surface of a document as will be adequate to reinforce badly degraded paper. This can be an adjustable preliminary step to achieving sufficient stability so that the so-treated pages can be subsequently spread and dipped into a live, preferably AB bath, for further in situ MC deposition.

This approach results in a diminished oxygen supply to M. This is compensated for by either carrying out the process in a higher pressure and/or greater concentration oxygen environment to force the molecules into the damp paper. Alternatively, oxygenating agents, such as peroxides, are supplied directly in the nutrient liquid to provide a higher dissolved oxygen supply for M. Also, the bubblebacter technique described elsewhere herein can be utilized to ensure that adequate oxygen is in the bubbles that are contacted with the surface of documents, particularly pages of books.

It is noteworthy that MC provides very strong thin films of excellent optical clarity. The MC also intertwines with the much larger wood cellulose. MC, unlike wood cellulose, has excellent wet strength. It also retains its properties at very extreme temperature conditions.

The in situ technique of the present invention also can be used to encase small items, such as microchips, and very large objects, such as, electronic components, i.e., circuit boards, and fragile or perishable archeological articles and artifacts. Such encasement provides long term protection from typical ambient conditions which are otherwise harmful to such objects. An excellent example of the utility of the present invention is evidenced by the following situation. The Mary Rose is a recently discovered Elizabethan Era ship found in the River Thames. The wood used in the ship's construction is soaked in water. Upon exposure to air, it is susceptible to rapid degradation. By permitting M, such as AB to form very thin continuous MC layers around the ship's parts, such degradation can be avoided or restrained.

Another important utility for the AB process of the invention is to fill the interstices within articles, such as those made from emulsion polymer castings or deposition processes, such as those made from elastomeric latices. The products made from such processes can be made in a wide variety of shapes and sizes. Often the process results in microscopic voids in the products.

A particularly preferred illustration of this facet of the inventive process is found in the manufacture of condoms from elastomeric latex. Many voids are found in the product and these must be rejected through responsible quality control. Nevertheless, the failure rate of condoms, even after passing quality control inspection, is in the order of 10 or 15%. In this era of accelerating AIDS risk, more and more of the population is turning to condoms as a reasonable, effective preventive measure. However, given the particularly deadly nature of AIDS, even the relatively small percentage of condom failure presently experienced is too high. When AB is used, either concomitantly with article formation or as an after treatment step in the aqueous stage of the process, the MC generated by AB fills the voids in the article from which the defects stem, increasing the inspection passage factor and lowering the failure rate in use. Utilizing MC in latex item manufacturing, such as condoms, should reduce rejection rate and increase reliability and safety. The MC can be used as a dispersion or emulsion in the elastomer latex at the time of article formation. Alternatively, it is applied as an after-step analogous to document strengthening as described herein.

Of course, personalized handcoverings can be made from MC using a suitable mold. These can be carried around as disposables for use in public rest rooms where AIDS virus transmission may be a problem.

In some instances, spreadable emulsions or solutions of MC can be prepared with a wide variety of appropriate thixotropic and other properties using agents such as glycerol, polyethylene glycol and carboxymethyl-cellulose (CMC). These can be then coated and spread on any suitable substrate such as a paper page. By itself or in combination with in situ processes described herein, composites possessing desired new properties can be produced by this non in situ coating process.

Because the MC produced by M or AB is not susceptible to inorganic acidic degradation, it can be fabricated into paper and other cellulosic products that are required to be resistant ab initio from degradation.

One exceptionally practical and useful application is to utilize MC for the preparation of currency. It will last considerably longer than conventional currency, even with comparable handling exposure. Perhaps, more significantly, however, the unique and preselected configuration of the microfibrils and their characteristic crystallinities, as well as other easily controlled modifications, easily prevent undetectable counterfeiting.

To produce the cellulose base for currency, a typical production run would be as follows: First, Acetobacter is innoculated into a standing culture of growth medium, and the cellulosic pellicle or membrane will form at the gas/liquid interface. The nutrient composition and time of culture will determine the thickness of the membrane. The strain used will determine some of the physical properties such as strength, opacity, etc. Once the cellulose membrane has been generated, it is then thoroughly cleaned. A typical cleaning procedure involves dilute alkali (NaOH) followed by or in combination with a detergent (such as Alconox), heating, and rinsing with distilled water. These processes result in the removal of non-cellulosic substances and cells and cell debris.

The never-dried sheet is now ready for post synthesis processing and drying. It can first be pressed to express most of the water, or it can be air dried. Additives can be in place before drying to modify the final physical properties of the dried product. The never-dried cellulose can be dyed or stained in such a manner to prevent counterfeiting. By doing these procedures before drying, one has additional control over such problems as accessibility of staining or dyeing, addition of binders for printing, etc.

The dried microbial cellulose paper for currency printing can then go through conventional processing, much as done with the specialty paper provided to the U.S. Treasury by Crane and Co. in Massachusetts.

Another variable would be to add microbial cellulose in very small quantities to the paper stock presently used (cotton rag and linen fibers) for U.S. currency production. By doing so, a sub-microscopic morphology is produced which is very unique and very difficult to counterfeit. This would be analgous to what Crane & Co. does by adding colored fibers to the paper stock for currency, but using microbial cellulose would be much more effective. It is important to note that the chemical composition of the base material for currency would still be exclusively cellulose. Addition of microbial cellulose to the conventional paper stock would also greatly increase the wearability and abrasion resistance of the paper stock, hence increasing the lifetime of the circulating currency.

Another important facet of this invention if referred to by its nickname as "bubblebacter." Simply stated, the microbial cellulose is grown on the surface of a bubble. The bubbles can be comprised of nutrient solution. Alternatively, they can be separately formed and a thin film of nutrient-containing M coated thereon to produce microthin layers of MC. The resulting product is usually a multicelled three dimensional foamed network of MC. In some instances, it can comprise a large single cell.

MC is not thermoplastic, and therefore, it cannot be foamed by conventional gaseous foaming agents. Nevertheless, the bubblebacter technique of this invention provides a means of producing a wide variety of multicellular MC structures. These can be designed and engineered to accomplish any structural, support or shape requirements.

Of course, viscosity modifying techniques can be utilized with the present processes to achieve special property goals and effects. The foamed bubblebacter version of MC can be made into any shape and used in any application in which non-cellular MC can be employed. It can be fabricated to have both low and high gas and liquid permeability. It will have exceptional applicability for those uses in which electric circuits are desired.

The surface structure of this multicellular material is especially well-adapted to thin film vapor deposited and epitaxial grown inorganics, such as superconductors, semiconductors and ordinary conductors, such as laminated metals, i.e., copper. All of this is of special significance because of the strength of thin gauge multicelled and dense MC articles. MC also has a low dielectric constant, adding to its already remarkable utility.

These approaches, as well as the more generic ones, such as mixing in other preselected materials with the MC as it is being formed to produce new shapes, forms and composites with widely varying properties are fully contemplated and comprehended by the scope of this invention.

Because MC is produced in a form so dissimilar from cellulose produced from cotton or wood degradation processes, it can be used effectively in process and environments in which conventional cellulose is not well-suited. In view of the exceptional strength, modulus, stability and resistance to temperature extremes possessed by MC, the multicellular embodiments will have a wide variety of applications not hitherto possible of attainment by existing multicellular polymers. MC, in both the dense and multicellular forms, is used as a filler in resins, particularly thermosetting resins. Both forms can be used also in existing porous membranes and filters to modify the capability of passing various materials. When used to fill interstices of porous materials, e.g., filters and membranes, the different components thereof can be selectively leached and dissolved to selectively alter porosity and permeation properties.

The present invention now will be further illustrated by certain examples and references which are provided for purposes of illustration only and are not intended to limit the present invention. Example 1

Direct Incorporation of Microbial Cellulose into Test Paper Documents

A 100 mm circle of Whatman #1 filter paper, and cut pieces (about 100 mm in diameter) of old archival paper documents (provided by Dr. Don Etherington of the Humanities Research Center of the University of Texas at Austin), including some old acid papers which were badly degraded and fragile, were added to a tray containing Schramm and Hestrin culture medium which was innoculated with strain NQ-5 of Acetobacter xylinum. The culture medium volume was minimal so that the archival and test paper would be sufficiently close to the gas/liquid interface that microbial cellulose would be generated in the vicinity of the test papers. After 6 days of growth, the microbial cellulose was found to have penetrated the test papers and be incorporated into them. Some of the old archival papers had printing, and the incorporated cellulose did not affect the reading of this print. The resultant composite which is pure cellulose was much stronger than the untreated test papers. The old documents and acid papers were so brittle that they would flake instantly with a light touch of the hand. The microbial cellulose incorporated into these test documents showed sufficient strength to be easily handled and moved by hand, without cracking or breaking. Thus, this document restoration technique is novel in -imparting strength while at the same time, its presence is not easily obvious to the naked eye. Also, that fact that only cellulose has been added to cellulose, is novel for this invention. Example 2

Carboxymethylcellulose/Microbial Cellulose in Document Restoration

A pellicle of microbial cellulose grown for 3 days in Schramm Hestrin medium was cleaned as described in Example 1 above, then impregnated while still wet with 1% glycerol to decrease brittleness. The wet glycerol impregnated pellicle was placed onto a polyethylene sheet. Then the test document was placed on top of the wet microbial cellulose. Than a 1% aqueous solution of carboxymethylcellulose was hand rubbed into the document after it was pressed to the test document and squeeze dried. The composite was then air dried for 24 hours. The resultant adhesion of the microbial cellulose to the test document was excellent, imparting a much greater mechanical strength to the brittle test document.

Example 3

Synthesis of Microbial Cellulose on the Surface of Thin Films or Foams (Bubblebacter Technique)

Acetobacter xylinum strain NQ-5 was grown on Schramm Hestrin liquid medium in an Erlenmeyer flask, and a 5 day culture was vigorously shaken to obtain an active innoculum of cellulose producing cells. To the supernatant of this mixture containing only cells and culture medium was added 0.5% (wt/vol) albumin which served as the foaming agent. 100 ml of thi^ innoculated medium was placed in the bottom of a 1 liter graduated cylinder and compressed air was sparged into the liquid at the bottom of the cylinder. The numerous small air bubbles caused a dense foam to form. The foam kept its shape and the bubbles did not break. After 1 hour, samples of the foam were taken to see if bacterial cellulose has been synthesized in association with the thin liquid foam films. Using polarization, darkfield, and electron microscopy, cellulose production was confirmed. Thus, the bacteria which were present initially in the liquid foam culture medium, synthesized a thin cellulose film. This synthesis can take place in as short a time as 10 minutes if a dense innoculum is used. The resultant cellulose morphological shape is exactly the same as the morphology of the albumin/culture medium foam bubbles. Thus, a new morphological form of cellulose has been generated. In addition to albumin, glycerol has been used as the foaming agent.

Many modifications and variations of the present invention are possible in light of the above teachings. Therefore, it will be apparent to one of ordinary skill in the art that many changes and modifications can be made thereto without departing from the spirit or scope of the invention as set forth herein.

PCT WORLD INTELLECTUAL PROPERTY ORGANIZATION International Bureau

INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT

(51) International Patent Classification 4_: (11) International Publication Number: WO 89/1

C12P 19/04; C12R 1/01, 1/02 A3

(43) International Publication Date: 14 December 1989 (14. C12R 1/05, 1/38, 1/41

(21) InternationalApplication Number: PCT/US89/02356

Published

(22)InternationalFiling Date: 30 May 1989 (30.05.89) With international search report

Before the expiration of the time limit for amending claims and to be republished in the event of the receip

(30)Priority data: amendments.

199,906 28 May 1988 (28.05.88) US

(88) Date of publication of the international search report:

8 February 1990 (08.02

(71X72)ApplicantandInventor: BROWN, R., Malcolm [US/ US]; 305 Skyline Drive, Austin, TX 78746 (US).

(74)Agent: PAUL, Thomas, D.; Fulbright & Jaworski, 1301 McKinney, Houston, TX 77010 (US).

(81)Designated States: AT (European patent), AU, BE (European patent), BR, CH (European patent), DE (European patent), DK, FI, FR (European patent), GB (European patent), IT (European patent), JP, KR, LU (European patent), NL (European patent), NO, SE (European patent).

(54)Title: MICROBIAL CELLULOSE COMPOSITES AND PROCESSES FOR PRODUCING SAME

(57)Abstract

Aprocess fortreating a variety of objects utilizing microbial cellulose produced in situ or applied as a film. Also discl is a process for manufacturing currency from microbial cellulose.

F \

FOR THEPURPOSES OF INFORMATION ONLY

Codes used to identify States party to the PCT on the front pages of pamphlets publishing international applications under the PCT.

AT Austria ES Spain MG Madagascar

AU Australia FI Finland ML Mali

BB Barbados FR France MR Mauritania

BE Belgium GA Gabon MW Malawi

BF Burkina Fasso GB United Kingdom NL Netherlands

BG Bulgaria HU Hungary NO Norway

BJ Benin rr Italy RO Romania

BR Brazil JP Japan SD Sudan

CA Canada KP Democratic People's Republic SE Sweden

CF Central African Republic of Korea SN Senegal

CG Congo KR Republic of Korea SU Soviet Union

CH Switzerland U Liechtenstein TD Chad

CM Cameroon LK Sri Lanka TG Togo

DE Germany, Federal Republic αf LU Luxembourg US United States of America

DK Denmark MC Monaco

Claims

What is Claimed Is:

1. A process for treating objects with microbial cellulose, comprising the steps of: culturing a cellulose-producing bacteria capable of reversing direction of cellulose ribbon extrusion in a nutrient medium, wherein said nutrient medium comprises an agent which interferes with crystallization, but not polymerization, of said cellulose; withdrawing said cellulose produced from said culture; and applying said cellulose to an object to reinforce and protect said object.

2. A process as claimed is Claim 1, wherein said bacteria is selected from the genera Acetobacter, Rhizobium, Agrobacterium Pseudomonas or Alcaligenes.

3. A process as claimed in claim 2, wherein said bacteria is selected from the genus Acetobacter.

4. A process as claimed in claim 3, wherein said bacteria is Acetobacter xylinum.

5. A process for treating objects with microbial cellulose, comprising the steps of: dampening an object with a solution comprising a cellulose-producing bacteria capable of reversing direction of cellulose ribbon extension, wherein said solution comprises an agent which interferes with crystallization, but polymerization, of said cellulose; and adjusting conditions to provide for in situ growth of cellulose from said bacteria.

6. A process as claimed in Claim 5, comprising the further step of: applying a cellulose layer to said object after said in situ cellulose formation, wherein said cellulose layer is produced by a cellulose-producing bacteria.

7. A process as claimed in Claim 6, comprising the further step of supplying an oxygenating agent to said nutrient medium.

8. A process as claimed in Claim 1, wherein said cellulose is applied to a paper document.

9. A process as claimed in Claim 1, wherein said cellulose is applied to a wooden structure.

10. A process as claimed in Claim 1, wherein said cellulose is applied to an electronic component.

11. A process as claimed in Claim 1, wherein said cellulose is applied to an elastomeric article.

12. A process as claimed in Claim 11, wherein said cellulose is formed in situ in said elastomeric article.

13. A process as claimed in Claim 1, wherein said cellulose is applied to a condom.

14. A process as claimed in Claim 1, wherein said agent comprises glycerol.

15. A process as claimed in Claim 1, wherein said agent comprises polyethylene glycol.

16. A process as claimed in Claim 1, wherein said agent comprises carboxymethyIcellulose.

17. A process for producing a currency product, comprising the steps of:

synthesizing microbial cellulose in non-agitated culture medium to make a non-woven integrated paper membrane

cleaning such a membrane to remove cells and non-cellulosic debris

adding such agents as to dye or stain or modify said cellulose

adding agents to identify microbial cellulose to retard counterfeiting

orienting the microfibrillar structure within the membrane while still wet by differential force applied to the membrane

drying the membrane in air or with solvent exchange or by freeze drying

printing currency on the microbial cellulose sheets

cutting microbial cellulose paper stock into currency.

18. The process of claim 17 including biosynthesizing said microbial cellulose in claim 17; and bonding microbial cellulose into or on the surface of conventional paper used in the manufacture of currency, thereby imparting a greater strength and resistance to counterfeiting

19. A process for manufacturing microbial cellulose, comprising the steps of: introducing a gas into a nutrient medium comprising a cellulose-producing bacteria to form bubbles in said medium; and controlling reaction conditions to provide for the formation of a foamed cellulose.

20. A process for manufacturing microbial cellulose, comprising the steps of: forming a multiplicity of bubbles in a substrate solution; applying a thin film of a solution comprising cellulose-producing bacteria; and controlling reaction conditions to produce a foamed cellulose.