Xylose and arabinose is the major constituents of hemicellulose, large quantities of which are found in agricultural waste, such as rice straw, corncobs, and parts of hard wood. Zhang et al. have described an improved Z. mobilis strain capable of producing ethanol from xylose and arabinose (Figure 1).
Table of Contents
What is xylose and arabinose?
Xylose and arabinose is the major constituents of hemicellulose, large quantities of which are found in agricultural waste, such as rice straw, corncobs, and parts of hard wood. Zhang et al. have described an improved Z. mobilis strain capable of producing ethanol from xylose and arabinose (Figure 1).
How is arabinose produced?
Production of L-arabinose On an industrial scale L-arabinose can be produced from gum arabic by acid hydrolysis followed by multiple purification procedures containing neutralization reaction, ion exchange and other chromatographic separations.
Is arabinose a pentose?
Arabinose is the second most abundant pentose in lignocellulosic biomass after xylose.
Why is arabinose added to the growth media?
Addition of arabinose sugar to the growth media will cause RNA polymerase to start transcribing the GFP gene (i.e. making mRNA molecules). The cellular machinery (e.g. ribosomes) will translate this mRNA into corresponding GFP protein.
How does arabinose control gene expression?
The ara operon is regulated by the AraC protein. If arabinose is absent, the dimer AraC protein represses the structural gene by binding to araI1 and araO2 and the DNA forms a loop, which prevents RNA polymerase from binding to the promoter of the ara operon, thereby blocking transcription.
What is the difference between L arabinose and D arabinose?
L-Arabinose is an arabinose isomer widely found in nature, while D-arabinose is less common. L-Arabinose is a constituent of many biopolymers that make up plant cell walls.
Where is L-arabinose found?
L-Arabinose and its functionality L-Arabinose is a rare type of sugar that naturally occurs in the hemicelluloses structure of most fruits and vegetables. The highest concentrations of L-Arabinose can be found in instant coffee, wine and sake.
Is arabinose a fiber?
The NSP of the AX-rich fiber contained 35.8% and 54.1% arabinose and xylose (% by wt), respectively, plus small amounts of mannose, galactose, and glucose. Thus, 89.9% of the NSP in AX-rich fiber was made up of AX….Composition of the arabinoxylan-rich fiber and of test meals.
| . | Content |
|---|---|
| Arabinose:xylose | 0.66 |
What is the structure of arabinose?
L-Arabinose
| PubChem CID | 439195 |
|---|---|
| Structure | Find Similar Structures |
| Molecular Formula | C5H10O5 |
| Synonyms | Ara Arabinopyranose Arabinopyranoside Arabinose L-Ara More… |
| Molecular Weight | 150.13 |
How does arabinose interact with the AraC protein help to turn on the RFP gene?
When arabinose is present, it binds to araC protein. RNA polymerase then binds to this complex & can then transcribe the rfp gene.
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