Production of low-cost nano-functionalized bacterial cellulose films for smart/intelligent packaging

Petroleum derived polymers such as polyethylene and polypropylene are commonly used in food packing industries while knowing the fact that these polymers cause serious threat to the ecosystem. Therefore, the development of low-cost, environmental friendly and biodegradable polymer to address these issues is an urgent need of the hour. Among various natural polymeric materials (polysaccharides, proteins, polyesters, and polylactides), bacterial nanocellulose (BNC) with extraordinary and differentiated properties is gaining special attention in food packaging industry. The BNC has several advantages over the plant-derived cellulose in terms of higher crystallinity (84-89%), excellent chemical purity i.e. free of hemicellulose, lignin, pectin, high tensile strength, improved water holding capacity, and moldability. Komagataeibacter (formerly Gluconacetobacter) is reported to be the best producer of BC in aerobic fermentation process. The main shortcoming of this process is the high cost of substrates which accounts 70-80% of the total production cost. To reduce the cost several low-cost substrates are utilized for production of BNC. In the addition to biodegradability, the modern-day food packaging system also notify the consumer about the quality of food and its suitability for consumption. In order to achieve this, smart packaging systems based on halochromic materials or colorimetric indicators are developed to monitor real-time freshness of food. These colorimetric indicators are sensitive to change in pH and/or chemical composition of the packaged food. This will help the consumer to easily identify the fresh food from the spoiled ones without opening the package. In addition to this, the colorimetric indicators obtained from natural source are devoid of toxicity and retains antimicrobials/antioxidants activities that can further enhance capability of packaged food from spoilage during storage. Therefore, the present study is focused on the production of low-cost BNC and its subsequent functionalization for smart packaging applications.