Komagataeibacter species are well‐recognized bionanocellulose ( BNC ) producers. This bacterial genus, formerly assigned to Gluconacetobacter , is known for its phenotypic diversity manifested by strain‐dependent carbon source preference, BNC production rate, pellicle structure, and strain stability. Here, we performed a comparative study of nineteen Komagataeibacter genomes, three of which were newly contributed in this work. We defined the core genome of the genus, clarified phylogenetic relationships among strains, and provided genetic evidence for the distinction between the two major clades, the K . xylinus and the K. hansenii . We found genomic traits, which likely contribute to the phenotypic diversity between the Komagataeibacter strains. These features include genome flexibility, carbohydrate uptake and regulation of its metabolism, exopolysaccharides synthesis, and the c‐di‐ GMP signaling network. In addition, this work provides a comprehensive functional annotation of carbohydrate metabolism pathways, such as those related to glucose, glycerol, acetan, levan, and cellulose. Findings of this multi‐genomic study expand understanding of the genetic variation within the Komagataeibacter genus and facilitate exploiting of its full potential for bionanocellulose production at the industrial scale.

The strains of the Komagataeibacter genus have been shown to be the most efficient bacterial nanocellulose producers. Although exploited for many decades, the studies of these species focused mainly on the optimisation of cellulose synthesis process through modification of culturing conditions in the industrially relevant settings. Molecular physiology of Komagataeibacter was poorly understood and only a few studies explored genetic engineering as a strategy for strain improvement. Only since recently the systemic information of the Komagataeibacter species has been accumulating in the form of omics datasets representing sequenced genomes, transcriptomes, proteomes and metabolomes. Genetic analyses of the mutants generated in the untargeted strain modification studies have drawn attention to other important proteins, beyond those of the core catalytic machinery of the cellulose synthase complex. Recently, modern molecular and synthetic biology tools have been developed which showed the potential for improving targeted strain engineering. Taking the advantage of the gathered knowledge should allow for better understanding of the genotype–phenotype relationship which is necessary for robust modelling of metabolism as well as selection and testing of new molecular engineering targets. In this review, we discuss the current progress in the area of Komagataeibacter systems biology and its impact on the research aimed at scaled-up cellulose synthesis as well as BNC functionalisation. Key points• The accumulated omics datasets advanced the systemic understanding of Komagataeibacter physiology at the molecular level.• Untargeted and targeted strain modification approaches have been applied to improve nanocellulose yield and properties.• The development of modern molecular and synthetic biology tools presents a potential for enhancing targeted strain engineering.• The accumulating omic information should improve modelling of Komagataeibacter’s metabolism as well as selection and testing of new molecular engineering targets.

We solved the 1.8 Å crystal structure of β‐fructofuranosidase from Bifidobacterium longum KN29.1 – a unique enzyme that allows these probiotic bacteria to function in the human digestive system. The sequence of β‐fructofuranosidase classifies it as belonging to the glycoside hydrolase family 32 (GH32). GH32 enzymes show a wide range of substrate specificity and different functions in various organisms. All enzymes from this family share a similar fold, containing two domains: an N‐terminal five‐bladed β‐propeller and a C‐terminal β‐sandwich module. The active site is located in the centre of the β‐propeller domain, in the bottom of a ‘funnel’. The binding site, −1, responsible for tight fructose binding, is highly conserved among the GH32 enzymes. Bifidobacterium longum KN29.1 β‐fructofuranosidase has a 35‐residue elongation of the N‐terminus containing a five‐turn α‐helix, which distinguishes it from the other known members of the GH32 family. This new structural element could be one of the functional modifications of the enzyme that allows the bacteria to act in a human digestive system. We also solved the 1.8 Å crystal structure of the β‐fructofuranosidase complex with β‐d‐fructose, a hydrolysis product obtained by soaking apo crystal in raffinose.Database Coordinates and structure factors have been deposited in the Protein Data Bank under accession codes: 3PIG and 3PIJStructured digital abstract ‐fructofuranosidase binds to ‐fructofuranosidase by x‐ray crystallography (View interaction)

This article presents a comparative analysis of bacterial cellulose membranes synthesized by several strains of the Komagataeibacter genus in terms of their specific physical, physico-chemical, and mechanical properties. Herein, the aim was to choose the most suitable microorganisms producing cellulosic materials with the greatest potential for the fabrication of bio-inspired nanocomposites. The selection was based on three main steps, starting from the evaluation of BNC biosynthetic efficiency with and without the addition of ethanol, followed by the assessment of mechanical breaking strength, and the physical parameters (compactness, structural integrity, appearance, and thickness) of the obtained biological materials. Ultimately, based on the performed screening procedure, three efficiently growing strains (K. hansenii H3 (6Et), K. rhaeticus K4 (8Et), and Komagataeibacter sp. isolated from balsamic vinegar (12Et)) were chosen for further modifications, enabling additional cellulose functionalization. Here, supplementation of the growth medium with five representative polymeric compounds (citrus/apple pectin, wheat starch, polyvinyl alcohol, polyethylene glycol) led to significant changes in BNC properties, especially dye loading abilities, mechanical strength, and water adsorption/retention capacities. The resulting nanocomposites can be potentially useful in various fields of medicine and industry, and in the future, they may become a practical and cost-effective competitor against commercial biomaterials currently available on the market.