title: Modified alginate and chitosan for lactic acid bacteria immobilization.
abstract: Beads with enhanced-stability acid media, which were based on alginate and chitosan functionalized by succinylation (increasing the anionic charges able to retain protons) or by acylation (improving matrix hydrophobicity), were developed for immobilization of bacterial cells. Beads (3 mm diameter) formed by ionotropic gelation with CaCl(2) presented good mechanical characteristics. After 30 min incubation of viable free Lactobacillus rhamnosus cells in simulated gastric fluid (pH 1.5), we noticed that the level of viable bacteria was undetectable. Bacterial immobilization in native-alginate-based beads generated a viable-cell count of 22-26%, whereas, when entrapped in succinylated alginate and chitosan beads, the percentage of viable cells was of 60 and 66%, respectively. Best viability (87%) was found for bacteria immobilized in N -palmitoylaminoethyl alginate, which affords a high protective effect, probably due to long alkyl pendants that improve the beads' hydrophobicity, limiting hydration in the acidic environment.
authors.affiliation: Department of Chemistry and Biochemistry, Université du Québec à Montréal, CP 8888, Succ. Centre-Ville, Montréal (Québec) H3C 3P8, Canada.
authors.forename: Canh
authors.initials: C
authors.lastname: Le-Tien
authors.forename: Mathieu
authors.initials: M
authors.lastname: Millette
authors.forename: Mircea-Alexandru
authors.initials: MA
authors.lastname: Mateescu
authors.forename: Monique
authors.initials: M
authors.lastname: Lacroix
mesh_terms: D000215:Acylation; D000464:Alginates / Q000737:chemistry*; D002122:Calcium Chloride / Q000737:chemistry; D002452:Cell Count; D018914:Cells, Immobilized; D048271:Chitosan / Q000737:chemistry*; D003692:Delayed-Action Preparations; D005782:Gels; D020723:Glucuronic Acid / Q000737:chemistry*; D006603:Hexuronic Acids / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D007778:Lactobacillus; D008863:Microspheres; D008970:Molecular Weight; D010168:Palmitates / Q000737:chemistry; D010194:Pancreatin / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D014783:Viscosity
chemical_list: D000464:Alginates; D003692:Delayed-Action Preparations; D005782:Gels; D006603:Hexuronic Acids; D010168:Palmitates; C032023:palmitoyl chloride; D010194:Pancreatin; D020723:Glucuronic Acid; D048271:Chitosan; D002122:Calcium Chloride