The physiological functions of the Cbp2D and Cbp2E proteins are important for insoluble cellulose-dependent growth in <i>Cellvibrio japonicus</i>

Bacterial contributions to fixed carbon turnover in the soil are increasingly being shown as vital to global nutrient cycling. Additionally, the discovery and characterization of bacterial polysaccharide deconstruction enzymes are fundamental for industrial and biomedical applications, such as the production of renewable fuels, sustainable detergents, and nutritional supplements. Our analysis of <i>C. japonicus</i> cellulose deconstruction is significant because it provides a roadmap for analyzing a suite of enzymes that may be functionally redundant and identifies those that are truly essential. Specifically, our results indicate that the functions of the Cbp2D and Cbp2E proteins, previously thought to have only a supporting or accessory role, in fact play a more direct part in cellulose deconstruction in <i>C. japonicus</i>. Furthermore, our results suggest that a strategy where recovery of soluble oligosaccharides is a priority to maximize the energetic economics for polysaccharide degradation in <i>C. japonicus</i>.