BACKGROUND Second generation hydrogen fermentation technologies using organic agricultural and forestry wastes are emerging. The efficient microbial fermentation of hexoses and pentoses resulting from the pretreatment of lingocellulosic materials is essential for the success of these processes. RESULTS Conversion of arabinose and glucose to hydrogen, by extreme thermophilic, anaerobic, mixed ...

Pentoses, including xylose and arabinose, are the second most prevalent sugars in lignocellulosic biomass that can be harnessed for biological conversion. Although Yarrowia lipolytica has emerged as a promising industrial microorganism for production of high-value chemicals and biofuels, its native pentose metabolism is poorly understood. Our previous study demonstrated that Y. lipolytica (ATCC...

Aspergilli are commonly found in soil and on decaying plant material. D-xylose and L-arabinose are highly abundant components of plant biomass. They are released from polysaccharides by fungi using a set of extracellular enzymes and subsequently converted intracellularly through the pentose catabolic pathway (PCP).In this study, the L-arabinose responsive transcriptional activator (AraR) is ide...

The utilization of simple sugars is widespread across all domains of life. In contrast, the breakdown of complex carbohydrates is restricted to a subset of organisms. A regulatory paradigm for integration of complex polysaccharide breakdown with simple sugar utilization was established in the mammalian gut symbiont Bacteroides thetaiotaomicron, whereby sensing of monomeric fructose regulates ca...

Studies involving lambda phage transduction of the D-arabinose utilization gene (dar+) in Escherichia coli K-12 indicated the product of this gene to be a transdominant activator. An apparent anomaly regarding this hypothesis exists in that a diploid recessive lysogen (lambda dar-/dar-) can spontaneously become capable of growth on D-arabinose.

1. In order to develop an improved differential sugar absorption test for simultaneously assessing intestinal permeability and lactose intolerance, methods were established for determining raffinose, lactose and L-arabinose in human urine. Using NAD(P)H-coupled enzymatic assays and fluorimetry, each sugar was measurable over a concentration range of approximately 3-300 mumol/l in diluted urine ...

We report here the construction, characterization, and application of a plasmid-based genetic system that reports the expression of a target promoter by effecting an irreversible, heritable change in a bacterial cell. This system confers strong repression of the reporter gene gfp in the absence of target promoter expression and utilizes the site-specific recombination machinery of bacteriophage...

Sinorhizobium meliloti is a soil bacterium that fixes nitrogen after being established inside nodules that can form on the roots of several legumes, including Medicago truncatula. A mutation in an S. meliloti gene (lpsB) required for lipopolysaccharide synthesis has been reported to result in defective nodulation and an increase in the synthesis of a xylose-containing glycan. Glycans containing...

BACKGROUND L-arabinose isomerases catalyse the isomerization of L-arabinose into L-ribulose at insight biological systems. At industrial scale of this enzyme is used for the bioconversion of D-galactose into D-tagatose which has many applications in pharmaceutical and agro-food industries. The isomerization reaction is thermodynamically equilibrated, and therefore the bioconversion rates is shi...