Modulation of bacterial nanocellulose crystallinity through carbon source-dependent metabolic pathways

Abstract

Bacterial nanocellulose (BNC) is a promising biomaterial, with unique properties for advanced applications. The present study investigated the influence of different carbon substrates on the crystallinity and properties of BNC produced by Komagataeibacter sucrofermentans DSM 15973T. BNC derived from glucose substrate showed lower crystallinity (⁓ 70%) than that from glycerol substrate (⁓ 82%). The causes of these variations were studied through genome analysis and exo-metabolite profiling. Carbon utilization patterns revealed differences in carbon flux and the exo-metabolite profile between carbon substrates. In the glucose medium, activation of the glucose dehydrogenase pathway led to the accumulation of gluconic acid. The gluconic acid interfered with inter-chain hydrogen bond formation, directly interacting with glucan hydroxy groups or indirectly reducing the BNC production rate. High levels of gluconic acid production reduced the BNC crystallinity by up to 60%. These variations in crystallinity affected the structural and mechanical properties of BNC. Our finding provides novel insight into the in-situ modulation of crystallinity through co-metabolites from carbon substrates and its impact on BNC properties.