In Situ Bioprocessing of Bacterial Cellulose with Graphene: Percolation Network Formation, Kinetic Analysis with Physicochemical and Structural Properties Assessment

The understanding of microbial growth dynamics during in situ fermentation and production of bacterial cellulose (BC) with impressive properties mimicking artificial nacre, suitable for commodity applications remains fundamentally challenging. Fabrication of BC/graphene films through a single step in situ fermentation with improved properties provides a sustainable replacement to the conventional chemical-based modification using toxic compounds. This work reports the effect of reduced graphene oxide (RGO) on in situ fermentation kinetics and demonstrates the formation of percolated-network in BC/RGO nanostructures. The evaluation of kinetic parameters shows that the specific growth rate reaches optimal values at 3 wt % RGO loadings, with mixed growth associated BC production behavior. The two-dimensional graphene sheets uniformly dispersed into a three-dimensional matrix of BC nanofibers via hydrogen-bonded interactions along with in situ reductions of RGO sheets, as confirmed from spectroscopic studies. This study also demonstrates the presence of percolated network-like structures between BC fibers and RGO platelets, which resulted in the formation of nanostructures with exceptional mechanical robustness and electrical conductivity. The physicochemical and structural properties of fabricated BC/RGO films were found to significantly depend upon the RGO compositions as well as fermentation conditions. We envision that the proposed ecofriendly and scalable technology for the formation of BC/RGO films with excellent inherent properties and performance will attract great interest for its prospective applications in flexible electronics.