Efficient and cost-effective bioethanol production from lignocellulosic materials requires co-fermentation of the main hydrolyzed sugars, including glucose, xylose, and L-arabinose. Saccharomyces cerevisiae is a glucose-fermenting yeast that is traditionally used for ethanol production. Fermentation of L-arabinose is also possible after metabolic engineering. Transport into the cell is the firs...

Corynebacterium glutamicum ATCC 31831 grew on l-arabinose as the sole carbon source at a specific growth rate that was twice that on d-glucose. The gene cluster responsible for l-arabinose utilization comprised a six-cistron transcriptional unit with a total length of 7.8 kb. Three l-arabinose-catabolizing genes, araA (encoding l-arabinose isomerase), araB (l-ribulokinase), and araD (l-ribulose...

Invasion of the intestinal epithelium is a critical step in Salmonella enterica infection and requires functions encoded in the gene cluster known as Salmonella Pathogenicity Island 1 (SPI-1). Expression of SPI-1 genes is repressed by L-arabinose, and not by other pentoses. Transport of L-arabinose is necessary to repress SPI-1; however, repression is independent of L-arabinose metabolism and o...

BACKGROUND Hydrolysates of plant biomass used for the production of lignocellulosic biofuels typically contain sugar mixtures consisting mainly of D-glucose and D-xylose, and minor amounts of L-arabinose. The yeast Saccharomyces cerevisiae is the preferred microorganism for the fermentative production of ethanol but is not able to ferment pentose sugars. Although D-xylose and L-arabinose fermen...

An Escherichia coli strain, ZUC99(pATX210), which can produce xylitol from L-arabinose at a high yield, has been created by introducing a new bioconversion pathway into the cells. This pathway consists of three enzymes: L-arabinose isomerase (which converts L-arabinose to L-ribulose), D-psicose 3-epimerase (which converts L-ribulose to L-xylulose), and L-xylulose reductase (which converts L-xyl...

Inducible switching between phenotypes is a common strategy of bacteria to adapt to fluctuating environments. Here, we analyze the switching kinetics of a paradigmatic inducible system, the arabinose utilization system in E. coli. Using time-lapse fluorescence microscopy of microcolonies in a microfluidic chamber, which permits sudden up- and down-shifts in the inducer arabinose, we characteriz...

AraC protein, which regulates expression of the l-arabinose operon in Escherichia coli, is a dimer whose DNA binding affinity for pairs of DNA half-sites is controlled by arabinose. Here we have addressed the question of whether the arabinose response of AraC requires the binding of one or two molecules of arabinose. This was accomplished by measuring the DNA dissociation rates of wild-type Ara...

The E-arabinose operon is under both positive and negative control by the product of its regulatory gene, UrQc. We have measured transcription of the arabinose genes by hybridization of 3H-labeled messenger RNA to single-stranded DNA from an arabinose transducing phage in order to study the effect of the regulatory gene on transcription. In strains in which the arabinose regulatory gene is comp...

The E-arabinose operon is under both positive and negative control by the product of its regulatory gene, UrQc. We have measured transcription of the arabinose genes by hybridization of 3H-labeled messenger RNA to single-stranded DNA from an arabinose transducing phage in order to study the effect of the regulatory gene on transcription. In strains in which the arabinose regulatory gene is comp...