Strain Selection and Characterization of Komagataeibacter hansenii for Bacterial Nanocellulose Production from Fruit Waste

Abstract

Bacterial nanocellulose (BNC) is a microorganism-derived homopolymer with a simpler, less harsh production route than its typical plant-based counterpart, offering unique properties valuable to high-end industries. This study aims to isolate and characterize bacteria that produce BNC from fermented rotten fruit waste, highlighting fermented starfruit as a selective and underexplored source for isolation. Among 80 isolates obtained using the fermented fruit juice method, strain RM-03 produced the highest cellulose concentration (0.092 g/100 mL) and was identified as Komagataeibacter hansenii (99.0% similarity). Using HS medium, it produced 0.277 ± 0.007 g/100 mL BNC at Day 16, a production within the range reported for some Komagataeibacter strains cultivated under comparable static, unoptimized conditions. Microscopy characterization revealed a dense network of nanofibers with an average fibril width of 35 nm. Spectroscopic and diffraction analyses confirmed cellulose type I with 78.24% crystallinity. The BNC exhibited excellent water-holding capacity (366.24%) and retained this moisture for up to 65 hours. These findings demonstrate that fermented rotten starfruit is a promising source for isolating functional BNC producers and that K. hansenii RM-03 shows strong potential for further bioprocess development and industrial applications.