A probiotic shield: Lactobacillus acidophilus immobilized in bacterial cellulose for a more sustainable release process and improved viability

BACKGROUND: Probiotics, defined as live microorganisms that confer a health benefit on the host when administered in adequate amounts, often require protective strategies to ensure their viability in food products. Immobilization in biopolymeric matrices presents a promising approach for enhancing bacterial resilience. This study focused on the fabrication of bacterial cellulose films as a platform for immobilizing Lactobacillus acidophilus. The physicochemical properties of the immobilized probiotic were investigated using Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The release profile and viability of the bacteria were also evaluated under simulated gastrointestinal environments (simulated gastric fluid and simulated intestinal fluid). RESULTS: The FTIR spectra confirmed the presence of the probiotic bacteria in the cellulose film. The FE-SEM results showed that the probiotic film had a smooth structure with reduced pores. XRD analysis also revealed that immobilizing probiotics in the cellulose film changes its crystalline structure to an amorphous state. TGA demonstrated the composite film's thermal stability, with mass losses of approximately 20% and 70.33% at 200 and 600 °C, respectively. The in vitro release profile demonstrated that immobilization significantly improved bacterial survival in simulated environments, particularly in simulated intestinal fluid. CONCLUSION: Collectively, these results indicate that the probiotic L. acidophilus was qualitatively incorporated in the cellulose film, and its survival rate was maintained during storage time. This suggests potential as an efficient carrier in the functional food and pharmaceutical industries.