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Researchers at The Chinese University of Hong Kong (CUHK) have created edible, transparent and biodegradable composite packaging for the food industry. The researchers have been developing the bio-derived food-grade packaging to reduce plastic food packaging as it accounts for a significant proportion of plastic waste in landfills. A team of researchers at CUHK began experimenting with bacterial cellulose (BC), an organic compound derived from certain types of bacteria, which has garnered attention as a sustainable and readily available non-toxic solution that could replace the use of plastics. They published their work in the peer-reviewed Journal of the Science of Food and Agriculture. Professor To Ngai from the Department of Chemistry at CUHK, said: "Extensive research has been conducted on BC, including its use in intelligent packaging, smart films and functionalised materials created through blending, coating and other techniques. These studies demonstrate the potential of BC as a replacement for single-use plastic packaging materials, making it a logical starting point for our research." He explained that the tensile strength and high versatility of BC are key to its potential. Unlike the cellulose found in the walls of plants, BC can be produced through microbial fermentation, eliminating the need for harvesting trees or crops. Ngai noted that the production method does not contribute to deforestation or habitat loss, which makes BC a more sustainable and environmentally friendly material alternative to plant cellulose. The report states that up until now, the widespread adoption of BC has been limited due to its “unfavourable” sensitivity to moisture in the air, which can detrimentally impact its physical properties. In the paper, the researchers detailed a novel approach to address the limitations of BC-based materials – by incorporating certain soy proteins into the structure and coating it with an oil-resistant composite, they “successfully created an edible, transparent and robust BC-based composite packaging”. “ does not require specific reaction conditions like chemical reactions, but rather a simple and practical method with mixing and coating,” Ngai added. “This approach offers a promising solution to the challenge of developing sustainable and environmentally friendly packaging materials that can replace single-use plastics on a large scale." The study demonstrated that the plastic alternative could be completely degraded within 1-2 months. According to the researchers, “Unlike other bio-derived plastics such as polylactic acid, the BC-based composite does not require specific industrial composting conditions to degrade”. Furthermore, the material developed is completely edible, which is said to make it safe “for turtles and other sea animals to consume without causing aquatic toxicity in the ocean”. Now, the researchers at CUHK hope to advance the versatility of modified BC films to make them suitable for a wider range of applications – specifically, developing a thermosetting glue that can create strong bonds between bacterial cellulose to allow it to be easily moulded into various shapes when heated. Ngai explained: "One of the main challenges with bacterial cellulose films is that they are not thermoplastic, which limits their potential for use in certain applications. By addressing this issue, we hope to make bacterial cellulose films more competitive with traditional plastics while maintaining their eco-friendliness.” The research aims to serve as a reminder that natural raw materials may already possess the necessary characteristics to perform beyond the functions of plastic packaging.