Friday, November 7, 2008

Xylose to Acetic Acid?

In hardwood, there are about 7 acetyl groups per 10 xylose units, which can be easily cleaved under alkali conditions.

Instead of converting xylose to ethanol by direct fermentation, it may make acetic acid via fermentation of xylose to acetic acid.

2C5H10O5→5C2H4O2

Therefore, 10 moles of xylose can generate 32 moles of acetic acid because 10 moles of xylose has 7 moles of acetic acid and 10 moles of xylose can be fermented to 25 moles of acetic acid.

Y.Y. LEE reported a total 76 wt% conversion and a maximum acetate concentration of 15.2g/L (2001); Parekh and Cheryan were able to achieve final broth concentrations of 102 g/l (as HAc) with 93% conversion of the glucose feedstock using dolime (Ca(OH)2Mg(OH)2) for pH control in a fed batch fermentation with cell recycle provided by cross-flow membrane filtration.

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