Synthesis, characterization, and food packaging application of bacterial nanocellulose film produced through biovalorization of tea factory waste

Abstract

The generation of tea waste by the tea factories during postharvest processing presents significant environmental and waste management challenges, as these by-products are often discarded with little to no further use. This study explores the innovative utilization of tea factory waste as a substrate for producing bacterial nanocellulose (BNC), a biomaterial with excellent mechanical properties and significant potential in industrial applications. The tea waste generated was valorized by brewing and subsequently supplemented with a symbiotic culture of bacteria and yeast to serve as a medium for BNC production. This research focuses on the production of high-tensile BNC films, emphasizing their application in biodegradable food packaging. The production of BNC from tea waste substrate is not only sustainable but also cost-effective, addressing the dual challenges of waste management and material sustainability. The yield of bacterial nanocellulose, measured on a dry weight basis, was significantly higher in tea waste media, with a production rate of 1.91 ± 0.15 g L−1, compared to 1.25 ± 0.13 g L−1 in the conventional Hestrin and Schramm (HS) media. This indicates that the tea waste substrate has a greater potential for producing BNC, demonstrating its superior efficiency over the conventional HS media. The BNC produced in tea waste substrate demonstrates exceptional tensile strength, with an average measured value of 93.7 ± 15.22 MPa, elongation at break of 4.96 ± 1.75%, and a Young’s modulus of 2.95 ± 1.27 GPa. The BNC also exhibits a maximum decomposition temperature (Tmax) of 328.8 °C, showing remarkable thermostability. These characteristics enhance its suitability for food packaging applications, where durability and material integrity are critical to ensuring the safety and preservation of packaged goods. Furthermore, the biodegradability of BNC offers a crucial advantage in reducing plastic waste, aligning with global efforts to minimize environmental pollution caused by conventional packaging materials. Comprehensive testing and characterization revealed that the produced BNC films possess flexibility, and other material properties, making them promising alternatives to non-biodegradable films in food packaging. This research highlights the potential of utilizing abundant and underutilized agro-industrial waste to produce high-value, eco-friendly food packaging materials, contributing to the advancement of sustainable practices in the packaging industry.