Biological Activity of Native and Low Molecular Weight Chitosan obtained by Steam Explosion Process

Pak J Biol Sci. 2018 Jan;21(9):441-447. doi: 10.3923/pjbs.2018.441.447.


Background and objective: Low molecular weight chitosan (LWCS) was interestingly used because of it's solubility and has good functional properties like antioxidant and antibacterial activity. This study aimed to evaluate antioxidant and antibacterial activity of chitosan and low molecular weight chitosan.

Materials and methods: Low molecular weight chitosan was obtained by physical and chemical hydrolysis using steam explosion process with steam pressure at 6 bar, temperature at 160°C and concentration of phosphotungstic acid at 0.1% w/v. The antioxidant activity was confirmed by radical DPPH scavenging activity, chelating metal ion value, inhibitory lipid peroxidation and antibacterial activity was confirmed by diffusion methods.

Results: LWCS had antioxidant activity higher than native chitosan on radical scavenging, chelating ion value and inhibition of lipid peroxidation. LWCS had higher inhibitory effect as antibacterial than native chitosan against tested bacteria, there were Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium, Streptococcus aureus and Bacillus subtilis.

Conclusion: It was concluded that LWCS had more powerful antioxidant and antibacterial activity than native chitosan.

Keywords: Antibacterial; antioxidant; chelating ion; low molecular weight chitosan; native chitosan; steam explosion process.

MeSH terms

  • Anti-Bacterial Agents / chemistry*
  • Antioxidants / chemistry*
  • Bacillus subtilis / drug effects
  • Biphenyl Compounds / chemistry
  • Chitosan / chemistry*
  • Escherichia coli / metabolism
  • Free Radicals / chemistry
  • Hydrolysis
  • Industrial Microbiology / methods
  • Lipid Peroxidation
  • Molecular Weight
  • Picrates / chemistry
  • Pseudomonas aeruginosa / drug effects
  • Salmonella typhimurium / drug effects
  • Solubility
  • Steam
  • Streptococcus / drug effects


  • Anti-Bacterial Agents
  • Antioxidants
  • Biphenyl Compounds
  • Free Radicals
  • Picrates
  • Steam
  • Chitosan
  • 1,1-diphenyl-2-picrylhydrazyl