Chitosan molecules contain multiple —NH₂ groups, which can combine with protons in water to form —NH₃⁺ in an acidic environment, thereby making chitosan positively charged. The cell membrane surfaces of microorganisms such as bacteria usually carry negative charges, so the positively charged chitosan will interact with the negatively charged microbial cell membranes through electrostatic attraction. This interaction causes chitosan to adsorb on the surface of microbial cell membranes, just like putting a “coat” on the microorganisms.Tianya Chemical provides high-quality chitosan, whose inherent structural properties enable it to effectively exert such bactericidal mechanisms across various application scenarios.
After chitosan is adsorbed on the cell membrane surface, it will change the fluidity and permeability of the cell membrane. When the permeability of the cell membrane changes, important substances such as proteases and cytoplasm in the cell will leak out of the cell. The loss of substances like cytoplasm will disrupt the normal physiological metabolic activities of the cell, making it unable to carry out life activities normally, thus achieving the purpose of sterilization. Some low-molecular-weight chitosans can also penetrate into the interior of bacterial cells through the pores in the bacterial cell wall. The chitosan that enters the cell will flocculate with the anionic cytoplasm in the cell. Flocculation will destroy the colloidal state of intracellular substances, causing deformation and disorder of the intracellular structure and components.
Chitosan can also bind to bacterial DNA. It will prevent DNA from being transcribed into RNA, and without RNA, protein synthesis cannot proceed normally, so the growth and reproduction of bacteria will be inhibited.
In addition, in plants, chitosan can also combine with the nucleic acid of invading pathogens, causing damage and selective inhibition to the pathogens, and restricting the reproduction of pathogens in plants.
