Preparation and evaluation of novel biodegradable Kombucha cellulose-based multi-layered composite tableware

A huge volume of single-use plastics is used for food packaging and cutlery which is associated with significant negative environmental impacts. In this study, the facile fabrication of multilayered composites using kombucha cellulose (KC) intercalated with tannery waste-gelatin as bio-adhesive using layer-by-layer assembly followed by hydraulic heat compression technique is reported. The prolonged fermentation of Kombucha tea resulted in KC pellicle with productivity of 385.5 ± 71.4 g/L and thickness of 2 ± 0.7 cm. The purification process improved the crystallinity index of the KC layer from 41.17% to 86.2%. Gelatin prepared using tannery trimming waste along with glucose at varying concentrations was used as interlayer coating between cellulose layers crosslinked by Maillard reactions resulting in the formation of biologically benevolent 'melanoidins'. Heat crosslinked composite (S8–20 H) with 8 layers of KC held with gelatin-glucose-myrobalan tertiary complex exhibited a high tensile strength of 47.7 MPa and a flexural strength of 117.27 MPa indicating high mechanical stiffness with the least density value of 0.71 g/cm3. The hardness values of the composites were between 54 and 76.6 Shore D hardness. The moisture susceptibility and thermal stability of the composites were found to be optimum for its use as cutlery. The composites were shaped into spoon-like tableware, ergonomically designed to appease, with baked food-like color, texture, and fragrance. The aqueous tolerance and surface oil resistance exhibited by the tableware were superior to traditional wood-based cutlery. By mechanical disintegration, the tableware is fully recyclable as a value-added bio-fertilizer for effective plant growth. This work presents a sustainable waste-to-wealth approach towards the preparation of food-safe, environment–friendly and biodegradable substitutes for plastics intended for tableware applications.