Phenotypic and genomic evidence for transparent cellulose, metabolic diversity, and stable cellulose production in the Acetobacteraceae

Abstract

ABSTRACTThe Acetobacteraceae are a family of microbes that use sugars from fruits, beverages and fermented foods to overproduce bacterial nanocellulose (BNC), a living material with broad applications in medicine and industry. Yet, the family has few complete, contiguous genome sequences available. Here, three different strains – a high production strain NQ5, a metabolic engineering host NCIB 8034, and a new isolate DS12 from kombucha were characterized and completede novogenomes assembled. Initial growth and yield experiments reveal a diversity of carbon source utilization profiles and BNC production rates, with NQ5 achieving the highest yield on glucose and DS12 having the narrowest utilization profile. All strains synthesize optically clear BNC. Genomic evidence assigns the DS12 isolate toKomagataeibacter nataicola,reassigns NCIB 8034 fromKomagataeibacter xylinustoKomagataeibacter oboediens,and supports NQ5 asNovacetimonas hansenii.Thebcsgene clusters that encode BNC synthesis are also diverse. The highest producing strain,N. hanseniiNQ5, has fewerbnccopies thanK. oboediensNQ5, indicating that copy number does not explain high productivity. Analysis also reveals the type and frequency of mobile genetic elements. Notably,N. hanseniiNQ5 has a paucity of transposons relative to other strains, which could explain the BNC production stability ofN. hanseniiNQ5 in culture. Thus, this work argues that Acetobacteraceae are metabolically diverse, and provides genomic evidence explaining beneficial BNC production characteristics ofN. hanseniiNQ5. Therefore, this work provides evidence for selection of appropriate BNC production strains.IMPORTANCEBacterial cellulose is an important material for biomedical applications like wound dressings. This study defines important characteristics of microbes that produce bacterial cellulose, namely their ability to process different sugars and features of their genomes that make cellulose yield more consistent. These findings will aid in the development of better bacterial cellulose production processes.