DNA sequence analysis of endoglucanase genes from Pseudomonas fluorescens subsp. cellulosa and Pseudomonas sp. NCIB 8634

Polysaccharide degradation systems of the saprophytic bacterium Cellvibrio japonicus

Study of recalcitrant polysaccharide degradation by bacterial systems is critical for understanding biological processes such as global carbon cycling, nutritional contributions of the human gut microbiome, and the production of renewable fuels and chemicals. One bacterium that has a robust ability to degrade polysaccharides is the Gram-negative saprophyte Cellvibrio japonicus. A bacterium with a circuitous history, C. japonicus underwent several taxonomy changes from an initially described Pseudomonas sp. Most of the enzymes described in the pre-genomics era have also been renamed. This review aims to consolidate the biochemical, structural, and genetic data published on C. japonicus and its remarkable ability to degrade cellulose, xylan, and pectin substrates. Initially, C. japonicus carbohydrate-active enzymes were studied biochemically and structurally for their novel polysaccharide binding and degradation characteristics, while more recent systems biology approaches have begun to unravel the complex regulation required for lignocellulose degradation in an environmental context. Also included is a discussion for the future of C. japonicus as a model system, with emphasis on current areas unexplored in terms of polysaccharide degradation and emerging directions for C. japonicus in both environmental and biotechnological applications.

Hidden domains and active site residues in beta-glycanase-encoding gene sequences?

Reading-frame corrective shifts in the nucleotide sequence upstream, within, or downstream from the putative coding region of several beta-glycanase-encoding genes reported in the literature reveal hidden active-site residues or even additional domains, including a cellulose-binding domain on a beta-mannanase-encoding gene. These findings also help in assigning, to cellulase family A, two enzymes previously found to lack sequence similarity with known cellulase families.