Comparative genomic analysis based on Zymomonas mobilis subsp. mobilis ATCC 29191 leads to insights regarding Zymomonas

Zymomonas mobilis is a bioethanol-producing α-proteobacterium that attracts interest due to its fermentation performances, simple biology and the availability of metabolically engineered strains. A recently sequenced Z. mobilis strain is the phenotypic centrotype of the subspecies mobilis, strain ATCC 29191 (Desiniotis et al., J. Bacteriol. 194; 5966-7). ATCC 29191 was originally isolated from palm wine fermentations in Congo, Africa, and has been studied as model for respiration and energy conversion in the genus. Compared to other Z. mobilis strains, it is also reported to be superior in polyfructan (levan) production. The genome of ATCC 29191 is divided into a circular chromosome and three plasmids. Genomic comparisons between representatives of the Z. mobilis subsp. mobilis and subsp. pomaceaetaxa led to insights regarding the core and accessory parts of their genomes and their overall structural differences. ATCC 29191 bears over 40 strain-specific genes and displays genomic rearrangements, many of which are due to an impressive number of chromosome- and plasmid-borne insertion elements belonging to the IS4 family. Among ATCC 29191 genes that exhibited strain specificity, identified were genes coding for tellurium resistance, as also genes determining metabolic, regulatory, and DNA biosynthesis/relocation processes. Due to its reportedly superior performances on sucrose substrates, an effort was made to determine all structural and regulatory genes of ATCC 29191 that contribute to sucrose uptake and hydrolysis, and fructose polymerization.