Carboxymethyl chitosan-N-alkylimine derivatives: Synthesis, characterization and use for preservation of symbiotic biofertilizer bacteria on chickpea seeds

Int J Biol Macromol. 2024 Mar;262(Pt 2):130057. doi: 10.1016/j.ijbiomac.2024.130057. Epub 2024 Feb 8.

Abstract

A series of carboxymethyl chitosan-N-alkylimine derivatives with side chain length of 4 to 10 carbons (CMCS-n, n = 4, 6, 8, 10) was prepared in a one-step solvent-free synthesis using Schiff base chemistry. The modified polysaccharides were characterized by their spectral, thermal and physical properties. The prepared polymers demonstrated an ability to spontaneous self-assembly with a clear correlation between critical aggregation concentration and the chain length of the alkyl substituent. N-alkylimine-CMCS derivatives were found to deliver hydrophobic (curcumin) and hydrophilic (ascorbic acid) active agents in unfavorable environments of water and oil, respectively. Then, N-alkylimine-CMCS derivatives were used as a platform for the delivery of symbiotic gram-positive bacteria Bacillus subtilis CJ onto chickpea seeds. These bacteria demonstrated a significantly higher survival rate (106 CFU/mL) in dried CMCS-6 derivative film than in other films tested. The seeds treated with N-alkylimine-CMCS coatings that contained B. subtilis CJ demonstrated up to 100-fold increase of this bacterial population on the seedlings in comparison to the pristine CMCS.

Keywords: Carboxymethyl chitosan; Chickpea seeds; Delivery system; Plant symbiotic bacteria; Schiff-base heterogeneous reaction.

MeSH terms

  • Bacteria
  • Chitosan* / chemistry
  • Cicer*
  • Curcumin* / chemistry
  • Water

Substances

  • Chitosan
  • Water
  • Curcumin