title: Chitooligosaccharides--preparation with the aid of pectinase isozyme from Aspergillus niger and their antibacterial activity.
abstract: An isozyme of pectinase from Aspergillus niger with polygalacturonase activity caused chitosanolysis at pH 3.5, resulting in low-molecular weight chitosan (86%), chitooligosaccharides (COs, 4.8%) and monomers (2.2%). HPLC showed the presence of COs with DP ranging from 2 to 6. Charcoal-Celite chromatography and re-N-acetylation of the COs followed by CD, IR, MALDI-TOF-MS and FAB-MS analyses revealed an abundance of chitobiose, chitotriose and chitotetraose. The COs-monomeric mixture showed a bactericidal effect towards Bacillus cereus and Escherichia coli more efficiently than native chitosan. Among the chitooligomers, the hexamer showed maximum antibacterial effect followed by the penta-, tetra-, tri- and dimers. Of the two monomers, only GlcN showed slight bacterial growth inhibition. SEM revealed bactericidal action patterns of COs-monomeric mixture towards B. cereus and E. coli.
authors.affiliation: Department of Biochemistry and Nutrition, Central Food Technological Research Institute, Mysore 570 020, India.
authors.forename: Farooqahamed S
authors.initials: FS
authors.lastname: Kittur
authors.forename: Acharya B
authors.initials: AB
authors.lastname: Vishu Kumar
authors.forename: Mandyam C
authors.initials: MC
authors.lastname: Varadaraj
authors.forename: Rudrapatnam N
authors.initials: RN
authors.lastname: Tharanathan
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D001234:Aspergillus niger / Q000201:enzymology*; D001409:Bacillus cereus / Q000187:drug effects / Q000648:ultrastructure; D048271:Chitosan / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D004926:Escherichia coli / Q000187:drug effects / Q000648:ultrastructure; D007527:Isoenzymes / Q000378:metabolism; D013058:Mass Spectrometry; D008826:Microbial Sensitivity Tests; D008855:Microscopy, Electron, Scanning; D009844:Oligosaccharides / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D011096:Polygalacturonase / Q000378:metabolism*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000900:Anti-Bacterial Agents; D007527:Isoenzymes; D009844:Oligosaccharides; D048271:Chitosan; D011096:Polygalacturonase