Property evaluation of bacterial cellulose nanostructures produced from confectionery wastes

Bacterial cellulose (BC) was produced using crude confectionery waste hydrolysates. The highest BC concentration (5.7 g/L) was achieved by Komagataeibacter sucrofermentans cultivated in static cultures at carbon to free amino nitrogen ratio of 24.5 g/g and pH 5. BC was treated with H2SO4, HCl and combined H2SO4-HCl at varying hydrolysis times to produce BC nanostructures (BCNs). FTIR spectra of all BCNs demonstrated typical cellulose vibration bands, while the peaks at 709 cm−1 and 746 cm−1 indicated the presence of Iα and Ιβ allomorphs. Dynamic light scattering analysis showed polydispersity, while lower hydrodynamic radiuses (Rh) of 56 nm and 385 nm were observed in the case of H2SO4-assisted hydrolysis after 48 h. The crystallinity index (CrI) of BC (77.9%) was lower than that of BCNs, which demonstrated CrIs up to 98.1%. The ζ-potential values of BCNs reached up to − 34.3 mV after 48 h hydrolysis using H2SO4. SEM micrographs showed rodlike-shaped nanocrystals with a strong tendency towards aggregation and overlapping. Overall, ex-situ modification of waste derived BC led to effective nanostructures production with distinct properties and potential applications as bio-based packaging reinforcing agent.