Semester of Graduation

August 2024

Degree

Master of Science (MS)

Department

School of Nutrition and Food Sciences

Document Type

Thesis

Abstract

Bacterial cellulose (BC), a biopolymer synthesized by certain bacterial strains, has garnered immense interest owing to its unique properties, purity, mechanical strength, and potential for diverse applications. This study investigated the factors influencing bacterial cellulose production by Komagataeibacter xylinus (ATCC 53524) and the antimicrobial activities of the film incorporated with silver nano particles. BC was synthesized through static fermentation and characterized using SEM, FTIR, TGA, tensile strength, and X-ray diffraction after drying by different techniques. The fermentation process was monitored by pH changes, decreasing from 6.0 on day 0 to 4.68 on day 21, indicating successful BC production. SEM analysis revealed an interconnected fibril network for BC, with purified BC free of bacterial cells. Freeze-dried BC exhibited the highest swelling ratio of 993.94%, followed by oven-dried (256.09%) and room temperature-dried (18°C) BC (141.30%) after 24 h. BC biocomposite films with pullulan demonstrated good thermal stability and mechanical properties, making them suitable for packaging applications. Silver nanoparticle formation was confirmed by a UV-Vis peak at 415 nm and a color change from transparent to yellowish-brown. The 75% BCAg-pullulan and 85% BCAg-pullulan formulations significantly inhibited the growth of Escherichia coli O157:H7, Listeria monocytogenes, Staphylococcus aureus, and Salmonella enterica with inhibition zones ranging from 22.167±0.247 mm, 23.667±0.252 mm, 26.167±0.176 mm, and 4.0 ± 0 mm , respectively compared to the control BC-pullulan discs without inhibition. These findings highlight the potential of BC-based biocomposite films for antimicrobial packaging applications.

Date

7-23-2024

Committee Chair

Adhikari, Achyut

Available for download on Friday, July 23, 2027

Included in

Food Science Commons

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