Sustainable food packaging using modified kombucha-derived bacterial cellulose nanofillers in biodegradable polymers†

Abstract

Incorporating nanoscale filler materials into polymers usually enhances mechanical properties, alters barrier characteristics, and enhances the visual appeal of consumer polymers. The growing recognition of the imperative to shift away from fossil-based, non-biodegradable polymers in single-use plastics and packaging materials toward fully renewable, recyclable, and/or biodegradable alternatives like PLA or PHBV has underscored the urgent need for the development of new, cost-effective, and scalable filler materials. Here, we demonstrate that the utilization of simple oligo-lactic acid modified bacterial cellulose (OLLA-g-BC) enhances the overall properties of commercial PLA and PHBV to a degree where it can directly compete with established conventional food packaging polymers. The key factor driving this enhancement lies in the uniform dispersion of the nanofiller throughout the bulk polymer, as visualized and confirmed through innovative 3D serial block face SEM analysis. The addition of 5% OLLA-g-BC increased the biodegradation rate of the nanocomposites without compromising their mechanical performance, leading to a ∼12% increase in Young's modulus for PLLA and a ∼14% decrease for PHBV. Filler incorporation resulted in a ∼23% and ∼45% decrease in oxygen permeability for PLLA and PHBV, respectively, while a ∼12% increase in water vapor permeability was observed for PLLA. Intensive investigations into the performance of nanocomposites clearly indicate that OLLA-grafted bacterial cellulose compound materials could significantly contribute to the realization of a fully circular, zero-waste economy.