Bacterial cellulose

Last updated
A wet microbial cellulose pellicle being removed from a culture Microbial cellulose pellicle.JPG
A wet microbial cellulose pellicle being removed from a culture
Nata de coco, a traditional food product from the Philippines made from fermenting coconut water with Komagataeibacter xylinus 09978jfCuisine Breads Fruits Baliuag Landmarks Bulacanfvf 30.jpg
Nata de coco , a traditional food product from the Philippines made from fermenting coconut water with Komagataeibacter xylinus

Bacterial cellulose is an organic compound with the formula (C
6 H
10 O
5)
n produced by certain types of bacteria. While cellulose is a basic structural material of most plants, it is also produced by bacteria, principally of the genera Komagataeibacter , Acetobacter , Sarcina ventriculi and Agrobacterium . Bacterial, or microbial, cellulose has different properties from plant cellulose and is characterized by high purity, strength, moldability and increased water holding ability. [1] In natural habitats, the majority of bacteria synthesize extracellular polysaccharides, such as cellulose, which form protective envelopes around the cells. While bacterial cellulose is produced in nature, many methods are currently being investigated to enhance cellulose growth from cultures in laboratories as a large-scale process. By controlling synthesis methods, the resulting microbial cellulose can be tailored to have specific desirable properties. For example, attention has been given to the bacteria Komagataeibacter xylinus due to its cellulose's unique mechanical properties and applications to biotechnology, microbiology, and materials science.

Contents

Historically, bacterial cellulose has been limited to the manufacture of the jelly-like desserts nata de piña and nata de coco , a Filipino food product. [2] [3] [4] With advances in the ability to synthesize and characterize bacterial cellulose, the material is being used for a wide variety of commercial applications including textiles, cosmetics, and food products, as well as medical applications. Many patents have been issued in microbial cellulose applications and several active areas of research are attempting to better characterize microbial cellulose and utilize it in new areas. [1]

History

As a material, cellulose was first discovered in 1838 by Anselme Payen. Payen was able to isolate the cellulose from the other plant matter and chemically characterize it. In one of its first and most common industrial applications, cellulose from wood pulp was used to manufacture paper. It is ideal for displaying information in print form due to its high reflectivity, high contrast, low cost and flexibility. The discovery of cellulose produced by bacteria, specifically from the Acetobacter xylinum , was accredited to A.J. Brown in 1886 with the synthesis of an extracellular gelatinous mat. [5] However, it was not until the 20th century that more intensive studies on bacterial cellulose were conducted. Several decades after the initial discovery of microbial cellulose, C.A. Browne studied the cellulose material obtained by fermentation of Louisiana sugar cane juice and affirmed the results by A.J. Brown. [6] Other researchers reported the formation of cellulose by other various organisms such as the Acetobacter pasteurianum, Acetobacter rancens, Sarcina ventriculi, and Bacterium xylinoides. In 1931, Tarr and Hibbert published the first detailed study of the formation of bacterial cellulose by conducting a series of experiments to grow A. xylinum on culture mediums. [7]

In the mid-1900s, Hestrin et al. proved the necessity of glucose and oxygen in the synthesis of bacterial cellulose. Soon after, Colvin detected cellulose synthesis in samples containing cell-free extract of A. xylinum, glucose and ATP. [8] In 1949, the microfibrillar structure of bacterial cellulose was characterized by Muhlethaler. [9] Further bacterial cellulose studies have led to new uses and applications for the material.

Biosynthesis

Chemical structure of cellulose Cellulose Sessel.svg
Chemical structure of cellulose

Bacterial sources

Bacteria that produce cellulose include Gram-negative bacteria species such as Acetobacter , Azotobacter , Rhizobium , Pseudomonas , Salmonella , Alcaligenes , and Gram-positive bacteria species such as Sarcina ventriculi. [10] The most effective producers of cellulose are A. xylinum, A. hansenii, and A. pasteurianus. Of these, A. xylinum is the model microorganism for basic and applied studies on cellulose due to its ability to produce relatively high levels of polymer from a wide range of carbon and nitrogen sources. [11]

General process

Biochemical Pathway for Cellulose Synthesis Biochemical Pathway for Cellulose Synthesis.jpg
Biochemical Pathway for Cellulose Synthesis

The synthesis of bacterial cellulose is a multistep process that involve two main mechanisms: the synthesis of uridine diphosphoglucose (UDPGIc), followed by the polymerization of glucose into long and unbranched chains (the β-1→4 glucan chain) by cellulose synthase. Specifics on the cellulose synthesis has been extensively documented. [12] [13] The former mechanism is well known while the latter still needs exploring. The production of UDPGIc starts with carbon compounds (such as hexoses, glycerol, dihydroxyacetone, pyruvate, and dicarboxylic acids) entering the Krebs cycle, gluconeogenesis, or the pentose phosphate cycle depending on what carbon source is available. It then goes through phosphorylation along with catalysis, followed by isomerization of the intermediate, and a process known as UDPGIc pyrophosphorylase to convert the compounds into UDPGIc, a precursor to the production of cellulose. The polymerization of glucose into the β-1→4 glucan chain has been hypothesized to either involve a lipid intermediate [14] or not to involve a lipid intermediate, [12] though structural enzymology studies and in vitro experiments indicate that polymerization can occur by direct enzymatic transfer of a glucosyl moiety from a nucleotide sugar to the growing polysaccharide. [15] A. xylinum usually converts carbon compounds into cellulose with around 50% efficiency. [14]

Fermentation production

Bacterial Strains that Produce Cellulose
Micro­organismCarbon sourceSupple­mentCulture time (h)Yield (g/L)
A. xylinum BRCSglucoseethanol, oxygen5015.30
G. hansenii PJK (KCTC 10505 BP)glucoseoxygen481.72
glucoseethanol722.50
Aceto­bacter sp. V6glucoseethanol1924.16
Aceto­bacter sp. A9glucoseethanol19215.20
A. xylinum ssp. Sucro­fermentans BPR2001molassesnone727.82
fructoseagar oxygen7214.10
fructoseagar5612.00
fructoseoxygen5210.40
fructoseagar oxygen448.70
A. xylinum E25glucoseno1683.50
G. xylinus K3mannitolgreen tea1683.34
G. xylinus IFO 13773glucoselignosulphonate16810.10
A. xylinum NUST4.1glucosesodium alginate1206.00
G. xylinus IFO 13773sugar cane molassesno1685.76
G. xylinus sp. RKY5glycerolno1445.63
Glucon­aceto­bacter sp. St-60-12 and Lacto­bacillus Mali JCM1116 (co-culture)sucroseno724.20

Cellulose production depends heavily on several factors such as the growth medium, environmental conditions, and the formation of byproducts. The fermentation medium contains carbon, nitrogen, and other macro and micro nutrients required for bacteria growth. Bacteria are most efficient when supplied with an abundant carbon source and minimal nitrogen source. [16] Glucose and sucrose are the most commonly used carbon sources for cellulose production, while fructose, maltose, xylose, starch, and glycerol have been tried. [17] Sometimes, ethanol may be used to increase cellulose production. [18] The problem with using glucose is that gluconic acid is formed as a byproduct which decreases the pH of the culture and in turn, decreases the production of cellulose. Studies have shown that gluconic acid production can be decreased in the presence of lignosulfonate. [19] Addition of organic acids, specifically acetic acid, also helped in a higher yield of cellulose. [20] Studies of using molasses medium in a jar fermentor [21] as well as added components of sugarcane molasses [22] on certain strains of bacteria have been studied with results showing increases in cellulose production.

Addition of extra nitrogen generally decreases cellulose production while addition of precursor molecules such as amino acids [23] and methionine improved yield. Pyridoxine, nicotinic acid, p-aminobenzoic acid and biotin are vitamins important for cellulose production whereas pantothenate and riboflavin have opposing effects. [24] In reactors where the process is more complex, water-soluble polysaccharides such as agar, [25] acetan, and sodium alginate [26] are added to prevent clumping or coagulation of bacterial cellulose.

The other main environmental factors affecting cellulose production are pH, temperature, and dissolved oxygen. According to experimental studies, the optimal temperature for maximum production was between 28 and 30 °C. [27] For most species, the optimal pH was between 4.0 and 6.0. [17] Controlling pH is especially important in static cultures as the accumulation of gluconic, acetic, or lactic acid decreases the pH far lower than the optimal range. Dissolved oxygen content can be varied with stirrer speed as it is needed for static cultures where substrates need to be transported by diffusion. [28]

Reactor based production

Static and agitated cultures are conventional ways to produce bacterial cellulose. Both static and agitated cultures are not feasible for large-scale production as static cultures have a long culture period as well as intensive manpower and agitated cultures produce cellulose-negative mutants alongside its reactions due to rapid growth. [29] Thus, reactors are designed to lessen culture time and inhibit the conversion of bacterial cellulose-producing strains into cellulose-negative mutants. Common reactors used are the rotating disk reactor, [30] the rotary biofilm contactor (RBC), [29] a bioreactor equipped with a spin filter, [31] and a reactor with a silicone membrane. [32]

Structure and properties

Types of cellulose [1]
GenusCellulose typeBiological role
AcetobacterExtracellular pellicle,
ribbons		Maintain aerobic
environment
AchromobacterRibbonsFlocculation
AerobacterFibrilsFlocculation
AgrobacteriumShort fibrilsAttachment to plants
AlcaligenesFibrilsFlocculation
PseudomonasNon-distinctFlocculation
RhozobiumShort fibrilsAttachment to plants
SarcinaAmorphousUnknown

Differences between plant and bacterial cellulose

As the Earth's most common organic material, cellulose can be classified into plant cellulose and bacterial cellulose, both of which are naturally occurring. Plant cellulose, which makes up the cell walls of most plants, is a tough, mesh-like bulkwork in which cellulose fibrils are the primary architectural elements. While bacterial cellulose has the same molecular formula as plant cellulose, it has significantly different macromolecular properties and characteristics. [8] In general, microbial cellulose is more chemically pure, containing no hemicellulose or lignin, has a higher water holding capacity and hydrophilicity, greater tensile strength resulting from a larger amount of polymerization, ultrafine network architecture. Furthermore, bacterial cellulose can be produced on a variety of substrates and can be grown to virtually any shape due to the high moldability during formation. [33] Additionally, bacterial cellulose has a more crystalline structure compared to plant cellulose and forms characteristic ribbon-like microfibrils. [1] A hallmark of microbial cellulose, these thin microfibrils are significantly smaller than those in plant cellulose, making bacterial cellulose much more porous. [9]

Three way branching point mechanism Branching point.png
Three way branching point mechanism

Macro structure

Cellulose is composed of carbon, oxygen, and hydrogen, and is classified as a polysaccharide, indicating it is a carbohydrate that exhibits polymeric characteristics. Cellulose is composed of straight chain polymers, whose base units of glucose are held together by beta-linkages. The structural role of cellulose in cell walls has been likened to that of the glass strands of fiberglass or to the supporting rods within reinforced concrete.[ citation needed ] Cellulose fibrils are highly insoluble and inelastic and, because of their molecular configuration, have a tensile strength comparable to that of steel.[ citation needed ] Consequently, cellulose imparts a unique combination of chemical resilience and mechanical support and flexibility to the tissues in which it resides. [34] Bacterial cellulose, produced by Acetobacter species, displays unique properties, including high mechanical strength, high water absorption capacity, high crystallinity, and an ultra-fine and highly pure fiber network structure. [35] One of the most important features of bacterial cellulose is its chemical purity. In addition to this, bacterial cellulose is stable towards chemicals and at high temperatures. [36] Bacterial cellulose has been suggested to have a construction like a ‘cage' which protects the cell from foreign material and heavy-metal ions, while still allowing nutrients to be supplied easily by diffusion. [2] [37] Bacterial cellulose was described by Louis Pasteur as "a sort of moist skin, swollen, gelatinous and slippery." Although the solid portion in the gel is less than one percent, it is almost pure cellulose containing no lignin and other foreign substances. [2] Although bacterial cellulose is obtained in the form of a highly swollen gel, the texture is quite unique and different from typical gels. Cellulose has a high swollen fiber network resulting from the presence of pore structures and tunnels within the wet pellicle. Plant cellulose water retention values 60%, while bacterial cellulose has a water retention value of 1000%. [33] The formation of the cellulose pellicle occurs on the upper surface of the supernatant film. A large surface area is important for a good productivity. The cellulose formation occurs at the air/cellulose pellicle interface and not at the medium/cellulose interface. Thus oxygen is an important factor for cellulose production. [1] After an inducing and a rapid growth period, the thickness increases steadily. Fibrils appear to be not necessarily linear but contain some "three-way branching points" along their length. This type of branching is considered to be related to the unique characteristics of this material and occurs from branching points produced by binary fission. [38]

Sizes of synthetic and naturally occurring fibers Sizes.png
Sizes of synthetic and naturally occurring fibers

Properties and characterization

Sheet-shaped material prepared from bacterial cellulose has remarkable mechanical properties. According to Brown, the pellicle of bacterial cellulose was "very tough, especially if an attempt was made to tear it across its plane of growth". [2] The Young's modulus for bacterial cellulose has been reported to be as high as 15 GPa across the plane of the sheet, whereas the highest values attained in the past by polymeric films or sheets is < 10GPa at most. The sheet's high Young's modulus has been attributed to the unique super-molecular structure in which fibrils of biological origin are preserved and bound tightly by hydrogen bonds. This Young's modulus does not vary with temperature nor the cultivation process used. The very high Young's modulus of this material must be ascribed to its super-molecular structure. [37] [38]

This property arises from adjacently aligned glucan chains participating in inter- and intrachain hydrogen bonding. [34] Bacterial cellulose subfibrils are crystallized into microfibrils which group to form bundles, that then form 'ribbons'. These fibers are two orders of magnitude thinner than cellulose fibers produced by pulping wood. [8] Today, it is known that the pellicle comprises a random assembly of fibrils (< 130 nm wide), which are composed of a bundle of much finer microfibrils (2 to 4 nm diameter). It is also known that the pellicle gives a film or sheet when dried if the shrinkage across the plane is restricted. [38] The ultrafine ribbons of microbial cellulose form a dense reticulated structure, stabilized by extensive hydrogen bonding. Bacterial cellulose is also distinguished from its plant counterpart by a high crystallinity index (above 60%). Two common crystalline forms of cellulose, designated as I and II, are distinguishable by X-ray, nuclear magnetic resonance (NMR), Raman spectroscopy, and infrared analysis. [8] Bacterial cellulose belongs crystallographically to Cellulose I, common with natural cellulose of vegetable origin, in which two cellulose units are arranged parallel in a unit cell. [2] [40] The term Cellulose I is used for this parallel arrangement, whereas crystalline fibrils bearing antiparallel polyglucan chains arise forming the thermodynamically stable Cellulose II. [34] The molecular arrangement in the sheet, confirmed by X-ray diffraction, was such that the molecular chain axis lay randomly perpendicular to the thickness such that the (1 1 0) plane was oriented parallel to the surface. [38]

Although cellulose forms a distinct crystalline structure, cellulose fibers in nature are not purely crystalline. In addition to the crystalline and amorphous regions, cellulose fibers contain various types of irregularities, such as kinks or twists of the microfibrils, or voids such as surface micropores, large pits, and capillaries. Thus, the total surface area of a cellulose fiber is much greater than the surface area of an ideally smooth fiber of the same dimension. The net effect of structural heterogeneity within the fiber is that the fibers are at least partially hydrated by water when immersed in aqueous media, and some micropores and capillaries are sufficiently spacious to permit penetration. [37]

Scanning electron microscopy of a fractured edge has revealed a pile of very thin layers. It is suggested that these fibrils in layers are bound through interfibrillar hydrogen bonds, just as in pulp-papers, but the density of the interfibrillar hydrogen bonds must be much higher as the fibrils are finer, hence the contact area is larger. [38]

Applications

Bacterial cellulose has a wide variety of current and potential future applications. Due to its many unique properties, it has been used in the food industry, the medical field, commercial and industrial products, and other technical areas. Bacterial cellulose is a versatile structural material, allowing it to be shaped in a variety of ways to accommodate different uses. A number of patents have been issued for processes involving this material. [41] . Bacterial cellulose pellicles were proposed as a temporary skin substitute in case of human burns and other dermal injuries [44. Fontana, J.D. et al (1990) "Acetobacter cellulose pellicle as a temporary skin substituite". .Applie d Biochemistry and Biotechnology (Humana Press) 24-25 : 253-264].

Food

The oldest known use of bacterial cellulose is as the raw material of nata de piña, a traditional sweet candy dessert of the Philippines. Several natural colored pigments (oxycarotenoids, anthocyanins and related antioxidants and free radical scavengers) were incorporated in to bacterial cellulose cubes in order to render the dessert more attractive [45. Fontana, J.D. et al (2017)  Handbook of Food Bioengineering, Elsevier / Academic Press, chapter 7 : New Insights on Bacterial Cellulose, pages 213-249]. Bacterial cellulose has also been used as a thickener to maintain the viscosity in food and as a stabilizing agent. Due to its texture and fiber content, it has been added to many food products as a dietary fiber. A specific example is Cellulon ®, which is a bulking agent used as a food ingredient to act as a thickener, texturizer, and/or calorie reducer. [42] Microbial cellulose has also been used as an additive in diet beverages in Japan since 1992, specifically kombucha, a fermented tea drink. [9]

Commercial products

Bacterial cellulose also has wide applications in commercial industries. In papermaking, it is used as an ultra-strength paper and as a reticulated fine fibre network with coating, binding, thickening and suspending characteristics. [35] Due to its high sonic velocity and low dynamic loss, bacterial cellulose has been used as an acoustic or filter membrane in hi-fidelity loudspeakers and headphones as marketed by the Sony Corporation. [2] Bacterial cellulose is also used as an additive in the cosmetic industry. Furthermore, it is being tested in the textile industry, with the possibility of manufacturing cellulose based clothing. [35]

Medical

In more modern applications, microbial cellulose has become relevant in the medical sector. It has been tested and successfully used as a wound dressing, especially in burn cases. Studies have shown that burns treated with microbial cellulose coverings healed faster than traditional treatments and had less scarring. The microbial cellulose topical applications are effective due to the cellulose's water holding ability and water vapor permeability. The high water holding ability provides a moist atmosphere at the injury site, which is critical in healing, while the wicking ability allows seepage from the wound to be removed from the site. Also, the microbial cellulose molds very well to the surface of the skin, providing a conformal covering even in usually difficult places to dress wounds, such as areas on the face. This technique has been so successful that commercial microbial cellulose products, such as Biofill ®, have been developed. [1] Another microbial cellulose commercial treatment product is XCell produced by the Xylos Corporation, which is mainly used to treat wounds from venous ulcers. [43] Studies have also been performed where traditional gauze dressings are treated with a microbial cellulose biopolymer to enhance the properties of the gauze. In addition to increasing the drying time and water holding abilities, liquid medicines were able to be absorbed by the microbial cellulose coated gauze, allowing them to work at the injury site. [44]

Microbial cellulose has also been used for internal treatments, such as bone grafts and other tissue engineering and regeneration. A key ability of microbial cellulose for medical applications is that it can easily be molded into various shapes while still retaining all of its useful properties. By molding microbial cellulose into long, hollow tubes, they can be used as replacement structures for several different areas, such as the cardiovascular system, the digestive tract, urinary tract, or the trachea. A recent application of microbial cellulose has been as synthetic blood vessels and stents. The cellulose can also be modeled into mesh membranes that can be used for internal replacement structures, such as the brain's outer membrane, the dura mater. In addition to replacement, these structures have also been used as grafts to interact with existing internal biological material. Microbial cellulose has also been used in guided tissue regeneration. [43] Bioprocess ® and Gengiflex ® are some of the common trademarked products of microbial cellulose that now have wide applications in surgery and dental implants. One example involves the recovery of periodontal tissues by separating oral epithelial cells and gingival connective tissues from the treated root surface. [1]

Current research/future applications

An area of active research on microbial cellulose is in the area of electronic paper. Currently, plant cellulose is used to produce the bulk of traditional paper, but due to its low purity it must be mixed with other substances such as lignin. However, due to microbial cellulose's higher purity and microfibril structure, it may prove to be an excellent candidate for an electronic paper substrate. Microbial cellulose can be fashioned into sheets approximately 100 micrometers thick, about the thickness of normal paper, by a wet synthesis process. The microbial cellulose produces a sturdy substrate with a microfibril structure that allows the paper to be implanted with dopants. Through the application of solutions to the microbial cellulose paper, conductive dopants and electrochromic dyes can be placed into the microfibril structure. The bistable dyes change from clear to dark upon the application of the appropriate voltages, which when placed in a pixel structure, would allow images to be formed. This technology is still in the research stage and has not yet been scaled to commercial production levels. Further research has been done to apply bacterial cellulose as a substrate in electronic devices with the potential to be used as e-book tablets, e-newspapers, dynamic wall papers, rewritable maps and learning tools. [45] Another possible example of bacterial cellulose use in the electronics industry includes the manufacture of organic light-emitting diodes (OLEDs). [35]

Challenges/limitations

Due to the inefficient production process, the current price of bacterial cellulose remains too high to make it commercially attractive and viable on a large scale. [35] Traditional production methods cannot produce microbial cellulose in commercial quantities, so further advancements with reactor based production must be achieved to be able to market many microbial cellulose products. [29]

See also

Related Research Articles

<span class="mw-page-title-main">Biopolymer</span> Polymer produced by a living organism

Biopolymers are natural polymers produced by the cells of living organisms. Like other polymers, biopolymers consist of monomeric units that are covalently bonded in chains to form larger molecules. There are three main classes of biopolymers, classified according to the monomers used and the structure of the biopolymer formed: polynucleotides, polypeptides, and polysaccharides. The Polynucleotides, RNA and DNA, are long polymers of nucleotides. Polypeptides include proteins and shorter polymers of amino acids; some major examples include collagen, actin, and fibrin. Polysaccharides are linear or branched chains of sugar carbohydrates; examples include starch, cellulose, and alginate. Other examples of biopolymers include natural rubbers, suberin and lignin, cutin and cutan, melanin, and polyhydroxyalkanoates (PHAs).

<span class="mw-page-title-main">Collagen</span> Most abundant structural protein in animals

Collagen is the main structural protein in the extracellular matrix found in the body's various connective tissues. As the main component of connective tissue, it is the most abundant protein in mammals, making up from 25% to 35% of the whole-body protein content. Collagen consists of amino acids bound together to form a triple helix of elongated fibril known as a collagen helix. It is mostly found in connective tissue such as cartilage, bones, tendons, ligaments, and skin. Vitamin C is vital for collagen synthesis, and Vitamin E improves the production of collagen.

<span class="mw-page-title-main">Cell wall</span> Outermost layer of some cells

A cell wall is a structural layer that surrounds some cell types, found immediately outside the cell membrane. It can be tough, flexible, and sometimes rigid. Primarily, it provides the cell with structural support, shape, protection, and functions as a selective barrier. Another vital role of the cell wall is to help the cell withstand osmotic pressure and mechanical stress. While absent in many eukaryotes, including animals, cell walls are prevalent in other organisms such as fungi, algae and plants, and are commonly found in most prokaryotes, with the exception of mollicute bacteria.

<span class="mw-page-title-main">Cellulose</span> Polymer of glucose and structural component of cell wall of plants and green algae

Cellulose is an organic compound with the formula (C
6H
10O
5)
n, a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell wall of green plants, many forms of algae and the oomycetes. Some species of bacteria secrete it to form biofilms. Cellulose is the most abundant organic polymer on Earth. The cellulose content of cotton fiber is 90%, that of wood is 40–50%, and that of dried hemp is approximately 57%.

<span class="mw-page-title-main">Hemicellulose</span> Class of plant cell wall polysaccharides

A hemicellulose is one of a number of heteropolymers, such as arabinoxylans, present along with cellulose in almost all terrestrial plant cell walls. Cellulose is crystalline, strong, and resistant to hydrolysis. Hemicelluloses are branched, shorter in length than cellulose, and also show a propensity to crystallize. They can be hydrolyzed by dilute acid or base as well as a myriad of hemicellulase enzymes.

<span class="mw-page-title-main">Polysaccharide</span> Long carbohydrate polymers such as starch, glycogen, cellulose, and chitin

Polysaccharides, or polycarbohydrates, are the most abundant carbohydrates found in food. They are long-chain polymeric carbohydrates composed of monosaccharide units bound together by glycosidic linkages. This carbohydrate can react with water (hydrolysis) using amylase enzymes as catalyst, which produces constituent sugars. They range in structure from linear to highly branched. Examples include storage polysaccharides such as starch, glycogen and galactogen and structural polysaccharides such as cellulose and chitin.

Acetic acid bacteria (AAB) are a group of Gram-negative bacteria which oxidize sugars or ethanol and produce acetic acid during fermentation. The acetic acid bacteria consist of 10 genera in the family Acetobacteraceae. Several species of acetic acid bacteria are used in industry for production of certain foods and chemicals.

<span class="mw-page-title-main">Exoenzyme</span> Exoenzyme

An exoenzyme, or extracellular enzyme, is an enzyme that is secreted by a cell and functions outside that cell. Exoenzymes are produced by both prokaryotic and eukaryotic cells and have been shown to be a crucial component of many biological processes. Most often these enzymes are involved in the breakdown of larger macromolecules. The breakdown of these larger macromolecules is critical for allowing their constituents to pass through the cell membrane and enter into the cell. For humans and other complex organisms, this process is best characterized by the digestive system which breaks down solid food via exoenzymes. The small molecules, generated by the exoenzyme activity, enter into cells and are utilized for various cellular functions. Bacteria and fungi also produce exoenzymes to digest nutrients in their environment, and these organisms can be used to conduct laboratory assays to identify the presence and function of such exoenzymes. Some pathogenic species also use exoenzymes as virulence factors to assist in the spread of these disease-causing microorganisms. In addition to the integral roles in biological systems, different classes of microbial exoenzymes have been used by humans since pre-historic times for such diverse purposes as food production, biofuels, textile production and in the paper industry. Another important role that microbial exoenzymes serve is in the natural ecology and bioremediation of terrestrial and marine environments.

<span class="mw-page-title-main">Polyhydroxyalkanoates</span> Polyester family

Polyhydroxyalkanoates or PHAs are polyesters produced in nature by numerous microorganisms, including through bacterial fermentation of sugars or lipids. When produced by bacteria they serve as both a source of energy and as a carbon store. More than 150 different monomers can be combined within this family to give materials with extremely different properties. These plastics are biodegradable and are used in the production of bioplastics.

<span class="mw-page-title-main">Fibril</span> Thin Fibre

Fibrils are structural biological materials found in nearly all living organisms. Not to be confused with fibers or filaments, fibrils tend to have diameters ranging from 10–100 nanometers. Fibrils are not usually found alone but rather are parts of greater hierarchical structures commonly found in biological systems. Due to the prevalence of fibrils in biological systems, their study is of great importance in the fields of microbiology, biomechanics, and materials science.

<span class="mw-page-title-main">Natural fiber</span> Fibers obtained from natural sources such as plants, animals or minerals without synthesis

Natural fibers or natural fibres are fibers that are produced by geological processes, or from the bodies of plants or animals. They can be used as a component of composite materials, where the orientation of fibers impacts the properties. Natural fibers can also be matted into sheets to make paper or felt.

<span class="mw-page-title-main">SCOBY</span> Symbiotic culture of bacteria and yeast

Symbiotic culture of bacteria and yeast (SCOBY) is a culinary symbiotic fermentation culture (starter) consisting of lactic acid bacteria (LAB), acetic acid bacteria (AAB), and yeast which arises in the preparation of sour foods and beverages such as kombucha. Beer and wine also undergo fermentation with yeast, but the lactic acid bacteria and acetic acid bacteria components unique to SCOBY are usually viewed as a source of spoilage rather than a desired addition. Both LAB and AAB enter on the surface of barley and malt in beer fermentation and grapes in wine fermentation; LAB lowers the pH of the beer/wine while AAB takes the ethanol produced from the yeast and oxidizes it further into vinegar, resulting in a sour taste and smell. AAB are also responsible for the formation of the cellulose SCOBY.

<span class="mw-page-title-main">Cellulose synthase (UDP-forming)</span> Cellulose synthesizing enzyme in plants and bacteria

The UDP-forming form of cellulose synthase is the main enzyme that produces cellulose. Systematically, it is known as UDP-glucose:(1→4)-β-D-glucan 4-β-D-glucosyltransferase in enzymology. It catalyzes the chemical reaction:

<i>Shewanella oneidensis</i> Species of bacterium

Shewanella oneidensis is a bacterium notable for its ability to reduce metal ions and live in environments with or without oxygen. This proteobacterium was first isolated from Lake Oneida, NY in 1988, hence its name.

<span class="mw-page-title-main">Cyclic di-GMP</span> Chemical compound

Cyclic di-GMP is a second messenger used in signal transduction in a wide variety of bacteria. Cyclic di-GMP is not known to be used by archaea, and has only been observed in eukaryotes in Dictyostelium. The biological role of cyclic di-GMP was first uncovered when it was identified as an allosteric activator of a cellulose synthase found in Gluconacetobacter xylinus in order to produce microbial cellulose.

<span class="mw-page-title-main">Cellulose fiber</span> Fibers made with ethers or esters of cellulose

Cellulose fibers are fibers made with ethers or esters of cellulose, which can be obtained from the bark, wood or leaves of plants, or from other plant-based material. In addition to cellulose, the fibers may also contain hemicellulose and lignin, with different percentages of these components altering the mechanical properties of the fibers.

Polymers with the ability to kill or inhibit the growth of microorganisms such as bacteria, fungi, or viruses are classified as antimicrobial agents. This class of polymers consists of natural polymers with inherent antimicrobial activity and polymers modified to exhibit antimicrobial activity. Polymers are generally nonvolatile, chemically stable, and can be chemically and physically modified to display desired characteristics and antimicrobial activity. Antimicrobial polymers are a prime candidate for use in the food industry to prevent bacterial contamination and in water sanitation to inhibit the growth of microorganisms in drinking water.

<span class="mw-page-title-main">Nanocellulose</span> Material composed of nanosized cellulose fibrils

Nanocellulose is a term referring to nano-structured cellulose. This may be either cellulose nanocrystal, cellulose nanofibers (CNF) also called nanofibrillated cellulose (NFC), or bacterial nanocellulose, which refers to nano-structured cellulose produced by bacteria.

<i>Acetobacter aceti</i> Species of bacterium

Acetobacter aceti is a Gram-negative bacterium that moves using its peritrichous flagella. Louis Pasteur proved it to be the cause of conversion of ethanol to acetic acid in 1864. It is a benign microorganism which is present everywhere in the environment, existing in alcoholic ecological niches which include flowers, fruits, honey bees, water and soil. This microbe lives wherever sugar fermentation occurs. It typically grows on substrates rich in sugars, like glucose or other carbon sources. It thrives best in temperatures that range from 25 to 30 degrees Celsius with a max temperature of 35 degrees Celsius and in pH that ranges from 5.5 to 6.3. For a long time it has been used in the fermentation industry to produce acetic acid from alcohol. A. aceti is an obligate aerobe, which means that it requires oxygen to grow as oxygen is used as the terminal electron acceptor.

Komagataeibacter xylinus is a species of bacteria best known for its ability to produce cellulose, specifically bacterial cellulose.

References

  1. 1 2 3 4 5 6 7 Jonas, R.; Farah, Luiz F. (1998). "Production and application of microbial cellulose". Polymer Degradation and Stability. 59 (1–3): 101–106. doi:10.1016/S0141-3910(97)00197-3.
  2. 1 2 3 4 5 6 Iguchi, M.; Yamanaka, S.; Budhiono, A. (2000). "Bacterial cellulose' a masterpiece of nature's arts". Journal of Materials Science . 35 (2): 261–270. Bibcode:2000JMatS..35..261I. doi:10.1023/A:1004775229149. S2CID   81685441.
  3. ↑ Sutanto, Agus Tri (2012). "Pineapple Liquid Waste as Nata De Pina Raw Material". Makara, Teknologi. 16 (1): 63–67. doi: 10.7454/mst.v16i1.1286 . S2CID   56381771.
  4. ↑ Vergara, Benito S.; Idowu, Panna Melizah H.; Sumangil, Julia H. (1999). Nata de Coco: A Filipino Delicacy (PDF). National Academy of Sciences and Technology, Philippines. ISBN   9718538615. Archived (PDF) from the original on 2021-06-28. Retrieved 2021-03-07.
  5. ↑ Brown, A.J. J. Chem. Soc.,49,172, 432(1886);51,643(1887)
  6. ↑ Browne, C. A. (1906). "THE ANALYSIS OF SUGAR MIXTURES.1". Journal of the American Chemical Society. 28: 439–453. doi:10.1021/ja01970a001.
  7. ↑ Tarr, H.L.A., Hibbery, H. Can. J. Research, 4, 372 (1931)
  8. 1 2 3 4 A. Steinbuhel, "Bacterial Cellulose." Biopolymers. Weinheim: Wiley-VCH, 2001. Print.
  9. 1 2 3 Bajaj, I; Chawla, P; Singhal, R; Survase, S. "Microbial cellulose: fermentative production and applications". Food Technology and Biotechnology. 47 (2): 107–124.
  10. ↑ Shoda, M.; Sugano, Y. (2005). "Recent advances in bacterial cellulose production". Biotechnol. Bioprocess Eng. 10: 1–8. doi:10.1007/BF02931175.
  11. ↑ S. Bielecki, A. Krystynowicz, M. Turkiewicz, H. Kalinowska: Bacterial Cellulose. In: Polysaccharaides and Polyamides in the Food Industry, A. Steinbuchel, S.K. Rhee (Eds.), Wiley-VCH Verlag, Weinhein, Germany (2005) pp. 31-85
  12. 1 2 Brown, Jr (1987). "The biosynthesis of cellulose". Food Hydrocolloids. 1 (5–6): 345–351. doi:10.1016/S0268-005X(87)80024-3.
  13. ↑ Delmer, D.P.; Amor, Y. (1995). "Cellulose biosynthesis". Plant Cell. 7 (7): 987–1000. doi:10.1105/tpc.7.7.987. PMC   160898 . PMID   7640530.
  14. 1 2 Iannino, N.I. De; Couso, R.O.; Dankert, M.A. (1998). "Lipid-linked intermediates and the synthesis of acetan in Acetobacter xylinum". J. Gen. Microbiol. 134 (6): 1731–1736. doi: 10.1099/00221287-134-6-1731 .
  15. ↑ Morgan, Jacob L. W.; McNamara, Joshua T.; Fischer, Michael; Rich, Jamie; Chen, Hong-Ming; Withers, Stephen G.; Zimmer, Jochen (2016). "Observing cellulose biosynthesis and membrane translocation in crystallo". Nature. 531 (7594): 329–334. doi:10.1038/nature16966. ISSN   0028-0836. PMC   4843519 . PMID   26958837.
  16. ↑ Ramana, K.V.; Singh, L.; Singh, Lokendra (2000). "Effect of various carbon and nitrogen sources on cellulose synthesis by Acetobacter xylinum". World J. Microbiol. Biotechnol. 16 (3): 245–248. doi:10.1023/A:1008958014270. S2CID   83658095.
  17. 1 2 Masaoka, S.; Ohe, T.; Sakota, N. (1993). "Production of cellulose from glucose by Acetobacter xylinum". J. Ferment. Bioeng. 75: 18–22. doi:10.1016/0922-338X(93)90171-4.
  18. ↑ Park, J.K.; Jung, J.Y.; Park, Y.H. (2003). "Cellulose production by Gluconacetobacter hansenii in a medium containing ethanol". Biotechnol. Lett. 25 (24): 2055–2059. doi:10.1023/B:BILE.0000007065.63682.18. PMID   14969408. S2CID   6660565.
  19. ↑ Keshk, S.; Sameshima, K. (2006). "Influence of lignosulfonate on crystal structure and productivity of bacterial cellulose in a static culture". Enzyme and Microbial Technology. 40: 4–8. doi:10.1016/j.enzmictec.2006.07.037.
  20. ↑ Toda, K.; Asakura, T.; Fukaya, M.; Entani, E.; Kawamura, Y. (1997). "Cellulose production by acetic acid-resistant Acetobacter xylinum". J. Ferment. Bioeng. 84 (3): 228–231. doi:10.1016/S0922-338X(97)82059-4.
  21. ↑ Bae, S.; Shoda, M. (2005). "Statistical optimization of culture conditions for bacterial cellulose production using Box-Behnken design". Biotechnol. Bioeng. 90 (1): 20–28. doi:10.1002/bit.20325. PMID   15712301.
  22. ↑ Premjet, S.; Premjet, D.; Ohtani, Y. (2007). "The effect of ingredients of sugar cane molasses on bacterial cellulose production by Acetobacter xylinum ATCC 10245". Sen-I Gakkaishi. 63 (8): 193–199. doi:10.2115/fiber.63.193.
  23. ↑ Son, H.J.; Kim, H.G.; Kim, K.K.; Kim, H.S.; Kim, Y.G.; Lee, S.J. (2003). "Increased production of bacterial cellulose by Acetobacter sp. V6 in synthetic media under shaking culture conditions". Bioresour. Technol. 86 (3): 215–219. doi:10.1016/S0960-8524(02)00176-1. PMID   12688462.
  24. ↑ Matsunaga, M.; Tsuchida, T.; Matsushita, K.; Adachi, O.; Yoshinaga, F. (1996). "A synthetic medium for bacterial cellulose production by Acetobacter xylinum subsp. Sucrofermentans". Biosci. Biotechnol. Biochem. 60 (4): 575–579. doi:10.1271/bbb.60.575.
  25. ↑ Chao, Y.; Mitari, M.; Sugano, Y.; Shoda, M. (2001). "Effect of addition of water-soluble polysaccharides on bacterial production in a 50-L airlift reactor". Biotechnol. Prog. 17 (4): 781–785. doi:10.1021/bp010046b. PMID   11485444. S2CID   33497254.
  26. ↑ Zhou, L.L.; Sun, D.P.; Hu, L.Y.; Li, Y.W.; Yang, J.Z. (2007). "Effect of addition of sodium alginate on bacterial cellulose production by Acetobacter xylinum". J. Ind. Microbiol. Biotechnol. 34 (7): 483–489. doi: 10.1007/s10295-007-0218-4 . PMID   17440758.
  27. ↑ Hestrin, S.; Schramm, M. (1954). "Synthesis of cellulose by Acetobacter xylinum: II. Preparation of freeze-dried cells capable of polymerizing glucose to cellulose". Biochem. J. 58 (2): 345–352. doi:10.1042/bj0580345. PMC   1269899 . PMID   13208601.
  28. ↑ Shirai, A.; Takahashi, M.; Kaneko, H.; Nishimura, S.; Ogawa, M.; Nishi, N.; Tokura, S. (1994). "Biosynthesis of a novel polysaccharide by Acetobacter xylinum". Int. J. Biol. Macromol. 16 (6): 297–300. doi:10.1016/0141-8130(94)90059-0. PMID   7727342.
  29. 1 2 3 Kim, J.Y.; Kim, J.N.; Wee, Y.J.; Park, D.H.; Ryu, H.W. (2007). "Bacterial cellulose production by Gluconacetobacter sp. RKY5 in a rotary biofilm contactor". Appl. Biochem. Biotechnol. 137–140 (1–12): 529–537. doi:10.1007/s12010-007-9077-8. PMID   18478414. S2CID   38869200.
  30. ↑ Krystynowicz, A.; Czaja, W.; Wiktorowska-Jezierska, A.; Goncalves-Miskiewicz, M.; Turkiewicz, M.; Bielecki, S. (2002). "Factors affecting the yield and properties of bacterial cellulose". J. Ind. Microbiol. Biotechnol. 29 (4): 189–195. doi:10.1038/sj.jim.7000303. PMID   12355318. S2CID   505777.
  31. ↑ Jung, J.Y.; Khan, T.; Park, J.K.; Chang, H.N. (2007). "Production of bacterial cellulose by Gluconacetobacter hansenii using a novel bioreactor equipped with a spin filter". Korean J. Chem. Eng. 24 (2): 265–271. doi:10.1007/s11814-007-5058-4. S2CID   56424486.
  32. ↑ Yoshino, T.; Asakura, T.; Toda, K. (1996). "cellulose production by Acetobacter pasteurianus on silicone membrane". J. Ferment. Bioeng. 81: 32–36. doi:10.1016/0922-338X(96)83116-3.
  33. 1 2 Klemm, D.; Schumann, D.; Udhardt, U.; Marsch, S. (2001). "Bacterial synthesized cellulose — artificial blood vessels for microsurgery". Progress in Polymer Science. 26 (9): 1561–1603. doi:10.1016/S0079-6700(01)00021-1.
  34. 1 2 3 Ross, P.; Mayer, R.; Benziman, M. (1991). "Cellulose biosynthesis and function in bacteria". Microbiol. Mol. Biol. Rev. 55 (1): 35–58. doi:10.1128/mr.55.1.35-58.1991. PMC   372800 . PMID   2030672.
  35. 1 2 3 4 5 Vandamme, E.J.; Baets, S. De; Vanbaelen, A.; Joris, K.; Wulf, P. De (1998). "Improved production of bacterial cellulose and its application potential". Polymer Degradation and Stability. 59 (1–3): 93–99. doi:10.1016/S0141-3910(97)00185-7.
  36. ↑ Sun, D.; Yang, J.; Wan, X. (2010). "Bacterial cellulose/TiO2 hybrid nanofibers prepared by the surface hydrolysis method with molecular precision". Nanoscale. 2 (2): 287–292. Bibcode:2010Nanos...2..287S. doi:10.1039/b9nr00158a. PMID   20644807.
  37. 1 2 3 Lynd, L.; Weimer, P.; Van Zyl, WH; Pretorius, IS (2002). "Microbial Cellulose Utilization: Fundamentals and Biotechnology". Microbiology and Molecular Biology Reviews. 66 (3): 506–577. doi:10.1128/MMBR.66.3.506-577.2002. PMC   120791 . PMID   12209002.
  38. 1 2 3 4 5 Nishi, Y.; et al. (1990). "The structure and mechanical properties of sheets prepared from bacterial cellulose". Journal of Materials Science. 25 (6): 2997–3001. Bibcode:1990JMatS..25.2997N. doi:10.1007/BF00584917. S2CID   135518566.
  39. ↑ Yoshinaga, Fumihiro; Tonouchi, N.; Watanabe, K. (1997). "Research progress in production of bacterial cellulose by aeration and agitation culture and its application as a new industrial material". Biosci. Biotechnol. Biochem. 61 (2): 219–224. doi: 10.1271/bbb.61.219 .
  40. ↑ Kuga, S.; Brown, R. M. (1988). "Silver labeling of the reducing ends of bacterial cellulose". Carbohydrate Research. 180 (2): 345–350. doi:10.1016/0008-6215(88)80091-0.
  41. ↑ Legge, Raymond (1990). "Microbial cellulose as a speciality chemical". Biotechnology Advances. 8 (2): 303–319. doi:10.1016/0734-9750(90)91067-Q. PMID   14546639.
  42. ↑ Okiyama, A., Motoki, M. and Yamanaka, S., Food Hydeocoll., 1992, 6, 479.
  43. 1 2 Czaja, Wojciech; et al. (2007). "The Future Prospects of Microbial Cellulose in Biomedical Applications". Biomacromolecules. 8 (1): 1–12. doi:10.1021/bm060620d. PMID   17206781.
  44. ↑ Meftahi, A.; et al. (2009). "The effects of cotton gauze coating with microbial cellulose". Cellulose. 17: 199–204. doi:10.1007/s10570-009-9377-y. S2CID   97758926.
  45. ↑ Shah, J.; Brown, M. (2005). "Towards electronic paper displays made from microbial cellulose". Applied Microbiology and Biotechnology. 66 (4): 352–355. doi:10.1007/s00253-004-1756-6. PMID   15538556. S2CID   25566915.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.