Polyglucan is any

polysaccharide 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 wa ...

that contains

glucan A glucan is a polysaccharide derived from D-glucose, linked by glycosidic bonds. Glucans are noted in two forms: alpha glucans and beta glucans. Many beta-glucans are medically important. They represent a drug target for antifungal medications of ...

units. Specifically, polyglucan's are a structural polysaccharide. The basic polyglucan unit consists of a long linear chain of several hundred to many thousands D-glucose monomers attached with a type of covalent bond called,

glycosidic bonds A glycosidic bond or glycosidic linkage is a type of covalent bond that joins a carbohydrate (sugar) molecule to another group, which may or may not be another carbohydrate. A glycosidic bond is formed between the hemiacetal or hemiketal grou ...

. The point of attachment is O-glycosidic bonds, where a glycosidic oxygen links the glycoside to the reducing end sugar. Polyglucans naturally occur in the cell walls of bacteria. Bacteria produce this polysaccharide in a cluster near the bacteria's cells. Polyglucan's are a source of beta-glucans. Structurally, beta 1.3-glucans are complex glucose homopolymers binding together in a beta-1,3 configuration.

Types

The following are beta glucans

Function

Polyglucans are utilized as a carbon source for microbial

fermentation Fermentation is a metabolic process that produces chemical changes in organic substrates through the action of enzymes. In biochemistry, it is narrowly defined as the extraction of energy from carbohydrates in the absence of oxygen. In food ...

. Although polyglucan production has so far been promoted by nutrient limitation, it must be further enhanced to accommodate market demand. The combined strategies of cultivation design and

genetic engineering Genetic engineering, also called genetic modification or genetic manipulation, is the modification and manipulation of an organism's genes using technology. It is a set of technologies used to change the genetic makeup of cells, including t ...

are used for polyglucan productivity for bioethanol production. Polyglucans are also involved in another sector of the energy industry, acting as biopolymers to increase oil recovery. The polysaccharide is attached to the bacteria cells and then mixed in an

alkali In chemistry, an alkali (; from ar, القلوي, al-qaly, lit=ashes of the saltwort) is a basic, ionic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a ...

solution such as

sodium hydroxide Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly caustic base and alkali ...

to become soluble. After which, it is then pumped into the injection well. The reason it needs to be a fluid is so you can pump the polysaccharides into the reservoir, but then the polysaccharide needs to gel/solidify/precipitate in situ upon addition of another chemical in order to plug up the pore. The biopolymer is then combined and injected with water until it fills up at least 30% of the empty pores. Next, there is an injection of an acid solution or forming . This neutralizes the solution and allows for the precipitation of the biopolymer, polyglucans, inside the high-permeability zones. Evidence shows that the application of this polyglucan can reduce the permeability of approximately 80% of the high-permeability zones. Oil companies are able to benefit from the decreased permeability because oil tends to flow in areas with the highest permeability. They can also serve as dietary supplements.

Synthesis

Photosynthetic Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored in c ...

microorganisms A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in olde ...

, such as

cyanobacteria Cyanobacteria (), also known as Cyanophyta, are a phylum of gram-negative bacteria that obtain energy via photosynthesis. The name ''cyanobacteria'' refers to their color (), which similarly forms the basis of cyanobacteria's common name, blu ...

and

microalgae Microalgae or microphytes are microscopic algae invisible to the naked eye. They are phytoplankton typically found in freshwater and marine systems, living in both the water column and sediment. They are unicellular species which exist indiv ...

, are currently used for their polyglucan production. Since these organisms have high-photosynthetic activity and whole-year cultivation without utilization of arable land. The cultivation is done by modifying the nutrient supply and replacing the growth medium of the cyanobacteria and green microalgae since the control and manipulation of polyglucan metabolism necessitates the elucidation of the polyglucan production mechanism. These activities promote the growth of polyglucans from these organisms.

Clinical significance

The immune-modulation action of polyglucans has been known for over 40 years, after experiments showed that they stimulated the activation of macrophages through the activation of the complement system. The detection of the (1,3)-β-D-glucan in blood is also used as a means of identifying invasive or disseminated fungal infections. Although, a positive test does not render a diagnosis, and a negative test does not rule out infection. This test can aid in the detection of Aspergillus, Candida, and Pneumocystis jirovecii.

References

{{reflist Polysaccharides