Chitin Oligosaccharide and Chitosan Oligosaccharide

Front. Plant Sci., 22 April 2016

Sec. Plant Pathogen Interactions

Volume 7 - 2016 | https://doi.org/10.3389/fpls.2016.00522

Natural resources have been traditionally used in agriculture by humans. For example, crab and shrimp shell powder has been applied to control crop disease and improve soil fertility. On the other hand, chitin is an important structural component in fungal cell walls and can be degraded by plant chitinases to eradicate fungal infection. Plant cells can recognize chitin and chitin-derived molecules to elicit immune response. Since the 1980s, chitin and its deacetylation product chitosan have been used for crop farming as biopesticides, biofertilizers, seed coating formulation, and agricultural film.

In order to overcome the poor solubility obstacle to chitin and chitosan application, soluble chitin oligosaccharides and chitosan oligosaccharides are prepared from these polysaccharides. The effects of chitin oligosaccharides and chitosan oligosaccharides on crop disease control were validated by several researches. Several biopesticides or biofertilizers have been developed based on these two oligosaccharides. However, the quantity and quality of the research on chitin oligosaccharides is much better than that on chitosan oligosaccharides. Some papers even claimed that chitosan oligosaccharides had no effect on plant disease control. However, based on the previous works, just like chitin oligosaccharides, chitosan oligosaccharides are potent pathogen-associated molecular patterns (PAMP).

Chitin is the second most abundant biomass in the world and can be found in fungal cell walls and the exoskeletons of arthropods. Compared to chitin, chitosan is rare in nature and found only in the fungi that have deacetylase enzymes. Chitin oligosaccharide and chitosan oligosaccharide are the degradation products of chitin and chitosan. Chitin oligosaccharide and chitosan oligosaccharide are builtup with N-acetylglucosamine or glucosamine with a degree of polymerization (DP) from 2 to 10. The only difference is the acetyl group on the C2 of the sugar ring in Chitin oligosaccharide. The degree of acetylation (DA) is closely linked with the polysaccharides material, the chemical, or enzyme degradation methods, as well as modification of enzymes such as chitin deacetylase. The acetyl group is important to Chitin oligosaccharide function. For example, acetyl group is important to Chitin Oligosaccharide binding with its receptor. On the other hand, chitosan oligosaccharide, with only an amino group on C2, are cationic oligosaccharides, which are attracted to negatively charged materials, such as plant cell membrane. This character makes the function and mechanism of chitosan oligosaccharide more complicated.

Another issue in this field is the ability to define and differentiate Chitin oligosaccharide and chitosan oligosaccharide. Theoretically, Chitin oligosaccharide should have a 100% DA and chitosan oligosaccharide should have no acetylation. However, lots of oligosaccharides, called chitooligosaccharides (COS), contain both N-acetylglucosamine and glucosamine because of the varied preparation methods. Previous reports showed that COS may have different functions and functional mechanisms with a primary factor of DA difference. So, we strongly recommend that scientists and companies provide the detailed DA data when they discuss Chitin oligosaccharide or chitosan oligosaccharide, which should only be described as with the 100 and 0% DA oligosaccharides.

Chitin oligosaccharide and chitosan oligosaccharide, the degradation products of chitin and chitosan, have different physical characteristics from the polysaccharides, which are important for their functions. Chitin is insoluble in common solvents, whereas chitosan dissolves in aqueous acidic solutions. Low DP Chitin oligosaccharide ranging from 2 to 6 can be dissolved in neutral water. However, the Chitin oligosaccharide with DP > 6 are not easily dissolved in neutral water, which limits its application. On the other hand, all chitosan oligosaccharide have a good solubility in neutral water.

chitosan oligosaccharide production is inexpensive and effective using several advanced methods including physical, chemical, and biological techniques. Nowadays, the environmentally friendly enzymatic method is favored as a near perfect process, which can control the DP and DA of the products with low-cost. However, Chitin oligosaccharide production is still challenging with a small quantity of commercial products using chemical methods. Though many chtinases have been reported, enzymatic production of Chitin oligosaccharide is not very successful.

BZ Oligo mainly offer marine oligosaccharide standards and ingredients, containing alginate oligosaccharide, chitosan oligosaccharide, agar oligosaccharide and carrageenan oligosaccharide, which give business opportunities using these untapped oligosaccharides for biological applications targeting lab research, pharmacy, dietary supplement, sustainable agriculture and animal health. 

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