Armillaria mellea is a traditional Chinese medicinal and edible mushroom. Many cultured products of A. mellea have been used to develop commercial medicines in recent years. The chemical composition and activities of the major bioactive chemical components-polysaccharides-may be different because of differences in the raw materials used. Four polysaccharides (SP, CMP, CFBP and CFMP) were obtain...

Cofermentation of glucose, xylose, and arabinose is critical for complete bioconversion of lignocellulosic biomass, such as agricultural residues and herbaceous energy crops, to ethanol. We have previously developed a plasmid-bearing strain of Zymomonas mobilis (206C[pZB301]) capable of cofermenting glucose, xylose, and arabinose to ethanol. To enhance its genetic stability, several genomic DNA...

16S rRNA-based stable isotope probing identified active xylose- and glucose-fermenting Bacteria and active Archaea, including methanogens, in anoxic slurries of material obtained from a moderately acidic, CH(4)-emitting fen. Xylose and glucose were converted to fatty acids, CO(2), H(2), and CH(4) under moderately acidic, anoxic conditions, indicating that the fen harbors moderately acid-toleran...

Ethanol is renewable and safe fuel and it is mainly produced based on microbial fermentation. The present study aims to isolate and identify ethanol producing Zymomonas spp. from natural environments with characterization, optimization and evaluation of their ethanol productivity. Samples were screened for ethanol producing bacteria on RM medium. Ethanol producing isolates were selected for cha...

Native strains of Saccharomyces cerevisiae do not assimilate xylose. S. cerevisiae engineered for d-xylose utilization through the heterologous expression of genes for aldose reductase (XYL1), xylitol dehydrogenase (XYL2), and d-xylulokinase (XYL3 or XKS1) produce only limited amounts of ethanol in xylose medium. In recombinant S. cerevisiae expressing XYL1, XYL2, and XYL3, mRNA transcript leve...

During growth of the halophilic archaeon Haloarcula marismortui on D-xylose, a specific D-xylose dehydrogenase was induced. The enzyme was purified to homogeneity. It constitutes a homotetramer of about 175 kDa and catalyzed the oxidation of xylose with both NADP+ and NAD+ as cosubstrates with 10-fold higher affinity for NADP+. In addition to D-xylose, D-ribose was oxidized at similar kinetic c...

Pentose sugars can be an important energy source for ruminal bacteria, but there has been relatively little study regarding the regulation of pentose utilization and transport by these organisms. Selenomonas ruminantium, a prevalent ruminal bacterium, actively metabolizes xylose and arabinose. When strain D was incubated with a combination of glucose and xylose or arabinose, the hexose was pref...

BACKGROUND The production of bioethanol from lignocellulosic feedstocks will only become economically feasible when the majority of cellulosic and hemicellulosic biopolymers can be efficiently converted into bioethanol. The main component of cellulose is glucose, whereas hemicelluloses mainly consist of pentose sugars such as D-xylose and L-arabinose. The genomes of filamentous fungi such as A....

Coastal bermudagrass is a promising lignocellulosic feedstock for bioethanol production. It is well suited for the Southeastern United States where it is currently grown for hay production and nutrient management in animal farming operations. Prior experiments have generated sugar and sugar degradation data from the dilute acid pretreatment and enzymatic hydrolysis of bermudagrass over a range ...

BACKGROUND Lignocellulosic biomass is a promising renewable feedstock for biofuel production. Acetate is one of the major inhibitors liberated from hemicelluloses during hydrolysis. An understanding of the toxic effects of acetate on the fermentation microorganism and the efficient utilization of mixed sugars of glucose and xylose in the presence of hydrolysate inhibitors is crucial for economi...