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Modified alginate and chitosan for lactic acid bacteria immobilization
Canh Le-Tien1, Mathieu Millette, Mircea-Alexandru Mateescu
1Department of Chemistry and Biochemistry, Université du Québec à Montréal, CP 8888, Succ. Centre-Ville, Montréal (Québec) H3C 3P8, Canada.
Biotechnology and Applied Biochemistry
|May 25, 2004
Summary
New alginate and chitosan beads protect bacteria in acidic environments. Modified beads significantly improved the survival rate of Lactobacillus rhamnosus in simulated gastric fluid, enhancing probiotic stability.
Area of Science:
- Biomaterials Science
- Microbiology
- Chemical Engineering
Background:
- Probiotic bacteria like Lactobacillus rhamnosus are sensitive to acidic conditions, limiting their efficacy.
- Developing protective delivery systems is crucial for enhancing probiotic survival in the gastrointestinal tract.
Purpose of the Study:
- To develop and evaluate novel alginate and chitosan beads for enhanced immobilization and acid resistance of bacterial cells.
- To investigate the impact of succinylation and acylation on bead properties and bacterial viability.
Main Methods:
- Alginate and chitosan were functionalized via succinylation or acylation to modify bead properties.
- Beads were formed using ionotropic gelation with calcium chloride (CaCl2).
- Bacterial viability of immobilized Lactobacillus rhamnosus was assessed after incubation in simulated gastric fluid (pH 1.5).
Main Results:
- Free Lactobacillus rhamnosus cells showed undetectable viability after 30 min in simulated gastric fluid.
- Immobilization in native alginate beads yielded 22-26% viable cells.
- Succinylated alginate and chitosan beads improved viability to 60% and 66%, respectively.
- N-palmitoylaminoethyl alginate beads achieved the highest viability (87%) due to enhanced hydrophobicity.
Conclusions:
- Functionalized alginate and chitosan beads offer superior protection for bacterial cells in acidic environments compared to native beads.
- Hydrophobicity, achieved through modifications like N-palmitoylaminoethyl alginate, plays a key role in protecting bacteria from acid-induced damage.
- These enhanced beads show significant potential for improving the delivery and efficacy of probiotics.