Antimicrobial lipopeptides from Bacillus amyloliquefaciens HY2–1: A reinforcing agent for enhancing fruit preservation efficacy of chitosan-based composite films

The development of multifunctional and biodegradable composite films represents a promising approach to enhancing food preservation. Herein, a chitosan-based composite film was designed by incorporating bacterial cellulose (as a mechanical reinforcement agent) and Bacillus amyloliquefaciens HY2–1 lipopeptides (as an antimicrobial component), with the aim of enabling its potential application in food packaging. A systematic investigation was conducted to evaluate the influence of varying HY2–1 lipopeptides concentrations on the key performance metrics of the composite films, including mechanical strength, barrier properties, antioxidant capacity, antimicrobial activity, and practical efficacy in fruit preservation. The results revealed a concentration-dependent enhancement in functional properties of the composite films with increasing of HY2–1 lipopeptides incorporation. At the optimal HY2–1 lipopeptides concentration of 2.4 mg/mL, the composite film demonstrated significantly improved antioxidant activity, with DPPH radical scavenging of 48.21% (8-fold that of the control) and ABTS radical scavenging of 60.73% (3-fold that of the control). Besides, the composite film exhibited significantly enhanced antimicrobial activities against a broad spectrum of pathogens, including Gram-positive bacteria ( Listeria monocytogenes and Staphylococcus aureus ), Gram-negative bacteria ( Escherichia coli ), and the fungal Penicillium digitatum , compared to the control film. Furthermore, the lipopeptides-incorporated composite film effectively preserved critical shelf-life indicators of citrus and strawberry under ambient storage conditions, including color retention, firmness maintenance, and nutritional content preservation, thereby demonstrating excellent practical preservation efficacy. Overall, this study designs a high-performance, fully bio-based composite film by integrating multifunctional lipopeptides into a chitosan matrix, presenting a potent and natural strategy to extend the shelf-life of perishable foods.